VOLUME III OF
SMALL FARM GRAIN STORAGE
BY
CARL LINDBLAD, PEACE CORPS
AND
LAUREL DRUBEN, VITA
ACTION/PEACE CORPS VOLUNTEERS IN TECHNICAL
PROGRAM & TRAINING JOURNAL ASSISTANCE
MANUAL SERIES NUMBER 2 VITA PUBLICATIONS
MANUAL SERIES NUMBER 35E
FIRST PRINTING SEPTEMBER 1976
SECOND PRINTING,
IN THREE VOLUMES JULY 1977
THIRD PRINTING JULY 1980
VITA
1600 Wilson Boulevard, Suite 500
Arlington, Virginia 22209 USA
Tel: 703/276-1900 . Fax: 703./243-1865
Internet: pr-info@vita.org
TABLE OF CONTENTS
INTRODUCTORY
The Purpose of the Manual
The People Who Prepared This Manual
The Sponsoring Organizations
How To Use This Manual
Introduction
Feedback
Storage Principles
Finding a Good Storage Place & Illustrations
Cleaning and Repairing Your Storage Place & Illustrations
Storing Grain in Basket Granaries
Instruction Sheet for Storing Grain in Baskets
Storing Grain in Sacks
Mixing Grain and Insecticides for Sack and Small-Container Storage
Treating Stacks of Bagged Grain -- Recommended Insecticides and Dosages
Storing Grain in Sacks: Summary
Airtight Storage
Storing in Gourds and Baskets
Storing Grain in Underground Pits
Storing Grain in Plastic Sacks, and Illustrations
Storing Grain in Metal Drums
Storing Grain in Metal Bins
Sheet Metal Silo
Fumigation of Small Quantities of Stored Grain: in Plastic Bags
under Plastic Sheets
and in Small Metal Containers or Silos
Storing in Earthen Structures
The Indian Pusa Bin
Improved Mudblock Silo
How to Use Your Mudblock Silo
Ferrocement for Grain Storage
An Overview of Grain Storage Uses for Ferrocement:
Thai Ferrocement Silo (Thailo)
Ferrocement-lined Underground Pits
and Other Ferrocement Grain Structures
Storing Grain in Cement/Concrete Structures
Brick Grain Storage Silo
The 4.5 Ton Cement Stave Silo
Instructions for Use of the Cement Stave Silo
Concrete Block Square Silos for Cooperative Storage
BIBLIOGRAPHY
CONVERSION TABLES
PURPOSE OF THE MANUAL
Small Farm Grain Storage is a set of how-to manuals. Together these
volumes provide a comprehensive overview of storage problems and
considerations as they relate to the small farmer. The authors
recommend the volumes be purchased as a set because the material forms
an excellent and complete working and teaching tool for development
workers in the field. This grain storage information can be adapted
easily to meet on-the-job needs; it has already been used as the
basis for a grain storage workshop and seminar in East Africa.
This set of publications retains the purpose of the original volume:
to bring together and to communicate effectively to field personnel
1) the basic principles of grain storage and 2) the practical solutions
currently being used and tested around the world to combat
grain storage problems. Only the format has been changed to:
* reduce printing and postage costs.
* permit updating and revising one volume at a time.
* provide smaller books that are easier to hold and use
than the large, single volume.
* make portions of the information available to the user
who is especially interested in only one or another of
the major aspects of small farm grain storage.
Of course, it is impossible to cover all storage situations in this
manual. But farmers who understand the basic, unchanging principles
of drying and storing grain are better able to adapt ideas, suggestions,
and technologies from other parts of the world to their own needs.
This material was prepared for use by those who work to facilitate
such understanding.
OVERVIEW OF THE MANUAL
Volume I, "Preparing Grain for Storage," discusses grain storage
problems as they are faced by small-scale farmers. This volume
contains explanations of the structure of grain, the relationship
between grain and moisture, the need for proper drying. One large
section contains detailed, fully illustrated plans for constructing
a variety of small-scale grain dryers.
Volume II, "Enemies of Stored Grain," is an in-depth study of two
major enemies: insects and rodents. Each is discussed in detail
with guidelines for 1) defining the size of the problem and 2) protecting
grain by both chemical and non-chemical means. This volume
includes dose and use information for a variety of pesticides, as well
as suggestions for preparing materials to be used in audio-visual
presentations.
Volume III, "Storage Methods," contains a survey of storage facilities
from the most traditional basket-type granary to metal bins and cement
silos. The emphasis in this volume is on improving existing facilities;
for example, there are detailed construction procedures for an
improved mud silo. Storage in underground pits and sacks also is
discussed. There are guidelines for using insecticides in storage
situations. The largest silo presented in detail is the 4.5 ton
cement stave silo.
THE PEOPLE WHO PREPARED THIS MANUAL
Carl Lindblad served as a Peace Corps Volunteer in Dahomey (Benin)
from 1972 to 1975. As a Volunteer, Lindblad worked in programs
designed to introduce and popularize a variety of grain storage
technologies. Upon his return to the United States, he began the task
of pulling together this manual as a consultant to VITA and Peace
Corps. At present, he serves as a consultant to a number of international
organizations, specializing in appropriate technologies for
grain storage -- in the areas of planning, extension and evaluation.
He spends much of his time in the field.
Laurel Druben served as an International Voluntary Services, Inc.
Volunteer in Laos from 1966 to 1968. While in Laos she was a
curriculum planner and a teacher of English as a second language.
Subsequently, she worked with a consulting firm evaluating government-funded
research and development projects, ran a small education-oriented
business, and was a free-lance consultant and proposal
writer. Druben, who has worked and lived in India and Micronesia,
as well as Southeast Asia, is Director of Communications for VITA.
Many thanks are due to the skilled and concerned people who worked to
make this manual possible:
A number of VITA people provided technical review, artwork,
and production skills:
Staff assistance -- John Goodell
Section 4, Vol. I materials -- Frederick Bueche
Technical review -- Douglas Barnes, Merle Esmay, Henry Highland,
Larry Van Fossen, Harold Willson, Kenton Harris
Artwork -- George Clark, John Goodell, Kenneth Lloyd,
Nicholas Reinhardt, Guy Welch
Thanks are extended to the following individuals and institutions
that provided invaluable assistance in early stages of work on
the manual:
Mary Ernsberger and Margot Aronson, Peace Corps Program and
Training Journal, USA
Brenda Gates, Peace Corps Information Collection & Exchange, USA
Tropical Stored Products Center, TPI, Great Britain
Henry Barre and Floyd Herum, Agricultural Engineering Department,
Ohio State University, USA
Department of Grain Science and Industry, Kansas State University,
USA
Agricultural Research Service, Department of Agriculture, USA
Extension Project Implementation Department, Ministry of
Agriculture, Ethiopia
F. W. Bennett, Midwest Research Institute, USA
Supervised Agricultural Credit Programs (SACP), Belize
Peter Giles, Nicaragua
Donald Pfalser, Agricultural Cooperatives Development International
(ACDI), USA
Technical Assistance Bureau, US Agency for International
Development (AID), USA
International Development Research Center, University of Alberta,
Canada
League for International Food Education (LIFE), USA
Institut de Recherches Agronomiques Tropicales et des Cultures
Vivrieres (IRAT), France
Post-Harvest Crop Protection Project, University of Hawaii, USA
Agricultural Engineering Service, FAO
African Rural Storage Center, IITA, Nigeria
Institute for Agricultural Research, Ahmadu Bello University,
Nigeria
Swaziland Rural Grain Storage Project
Jim McDowell, Food Technology and Nutrition Section, UNICEF, Kenya
Gordon Yadcuik, Centre Nationale de Recherches Agronomiques (CNRA),
Senegal
R. A. Boxall, Indian Grain Storage Institute, A.P., India
Siribonse Boon-Long, Ministry of Agriculture and Cooperation,
Thailand
Asian Institute of Technology, Chulalongkorn University, Thailand
Merrick Lockwood, Bangladesh Agricultural Research Council
International Rice Research Institute (IRRI), Philippines
Dante de Padua, University of Los Banos, Philippines
THE SPONSORING ORGANIZATIONS
Small Farm Grain Storage is part of a series of publications combining
Peace Corps practical field experience with VITA technical expertise
in areas in which development workers have special difficulties
finding useful resource materials.
ACTION/Peace Corps
Since 1961 Peace Corps Volunteers have worked at the grassroots level
in countries around the world in program areas such as agriculture,
public health, and education. Before beginning their two-year
assignments, Volunteers are given training in cross-cultural, technical,
and language skills. This training helps them to live and work
closely with the people of their host countries. It helps them, too,
to approach development problems with new ideas that make use of
locally available resources and are appropriate to the local cultures.
Recently Peace Corps established an Information Collection and
Exchange, so that these ideas developed during service in the field
could be made available to the wide range of development workers who
might find them useful. Materials from the field are now being
collected, reviewed, and classified in the Information Collection and
Exchange system. The most useful materials will be shared with the
development world. The Information Collection and Exchange provides
an important source of field-based research materials for the production
of how-to manuals such as Small Farm Grain Storage.
VITA
VITA people are specialists who volunteer their free time to answer
requests for technical assistance. Many VITA Volunteers have lived
and worked in other countries, often as Peace Corps Volunteers. Most
VITA people now work in the United States and other developed
countries where they are engineers, doctors, scientists, farmers,
architects, writers, artists, and so on. But they continue to work
with people in other countries through VITA. VITA Volunteers have
been providing technical assistance to the Third World for almost
20 years.
Requests for assistance come to VITA from many nations. Each request
is handled by a Volunteer with the right skills. For example, a
question about grain storage in Latin America might be handled by a
professor of agriculture, and a request for an improved planting
implement would go to an agricultural engineer. These VITA Volunteers,
many of whom have lived and worked in Third World countries, are
familiar with the special problems of these areas and are able to give
useful, and appropriate, answers.
VITA makes the expertise of VITA people available to a wide audience
through its publications program.
HOW TO USE THIS MANUAL
Development workers can use material from this manual in a number of
ways:
* Discussions. The manual provides clear presentations of grain
storage principles from which you can take material to lead
discussions with farmers and village leaders.
* Demonstrations. There are suggestions for demonstrations and
experiments which you might find helpful to illustrate grain
storage principles to farmers.
* Leaflets. Some of the material has been prepared in the form
of illustrated leaflets which can be used directly by you
with a farmer. They may require little or no adaptation by
you. But, if you prefer, you can use the structure of the
leaflet and substitute photographs specific to your area.
The material on rodent control in Volume II is a good example
of this kind of leaflet.
* Construction Plans. Many of the construction plans have been
simplified so that you will be able to work more closely with
the farmer. Some of the plans are fully illustrated. You
could add photographs of the work steps showing conditions in
your area. It is likely that after you introduce the material,
farmers can follow the instructions themselves. The
plans are written so that they would be easy to translate
into local languages. The Improved Maize Drying Crib in
Volume I is a good example of a step-by-step, illustrated
presentation.
* Checklists. Some of the material most likely to be useful for
small-scale farmers has been simplified and prepared in checklist
or hand-out form. This material would lend itself to
illustrations or photographs, so it can better fit into the
local situation. The checklists on controlling grain storage
insect pests included in Volume II are in this category.
* Examples. The appendices contain examples of leaflets that
have been prepared by development workers in several countries.
These examples have been included to give you some
idea of how the materials in this manual might be organized,
illustrated, translated, and presented to reach farmers.
* Sources. Wherever Possible, addresses are given so that you
can write for more information on a subject.
* Further Information. Other appendices contain information on
areas which, although important, cannot be covered fully within
the scope of this manual, for example, storage program
planning. A bibliography is provided at the end of each volume.
These are some of the aims of Small Farm Grain Storage. You will
probably find added uses. While it is not possible to make this
manual specific to the situations or culture of your particular area,
the information is presented so that you can do this very easily by
making additions or substitutions to the material.
Dimensions are given in metric units in the text and illustrations.
Conversion tables are provided at the end of each volume.
This manual will grow and change as its readers and users send in
additional material, comments, and ideas for new approaches to grain
storage problems and better ways to communicate with farmers. Your
own ideas and conclusions are welcome. A form has been included for
your comments. Please send us the results of your silo or dryer
building. Let us know how you used the information and how it could
be make even more useful to you. Tell us how you changed a plan to
fit local needs.
Your experience will help us to produce manuals of growing usefulness
to the world-wide development community.
REPLY FORM
For your convenience, a reply form has been inserted here. Please
send it in and let us know how the manual has helped or can be made
more helpful. If the reply form is missing from your book, just put
your comments, suggestions, descriptions of problems, etc., on a
piece of paper and send them to:
GRAIN STORAGE
3706 RHODE ISLAND AVENUE
MT. RAINIER, MD 20822
U.S.A.
<FIGURE 1>
51cp01.gif (437x437)
INTRODUCTION
Each farmer has some method of storing his grain. Any improvement in
this storage method must be made by steps the farmer sees as the right
ones for his situation or need. A farmer who stores his grain in sacks in
a corner of his house may not be ready to build a cement silo. Because
this farmer is afraid that thieves will take his grain, he may not want
to build any type of storage container outside his house.
For this farmer, trying a different drying method, or cleaning his storage
bags, or improving a stacking arrangement, or adding insecticides to sacked
grain could be a large, first step toward improved storage.
If a farmer is complaining about insects and rodents eating his stored
grain, you have an opening to say, "Let's do something about that problem."
But if the farmers in your area feel, "It's always been that way, and there
is nothing we can do about it," your first job is to convince the farmer
that there is something he can do about his problems.
Only you can introduce the material from this manual because you know the
area where you work. Hopefully, the earlier parts of this manual have
provided a lot of helpful information and material. If a farmer is not
ready to make improvements in his storage method, perhaps you can find the
material in this manual to put together leaflets which would help show
what change could do for him. One convinced farmer may be all it takes
to get things started.
Change only begins when farmers believe that new ideas and technologies can
be helpful to them. They may start out by making only small changes in
the method already being used. But the important point is that something
different is being tried. Then, when the farmer sees an improvement in
the quality of his stored grain, you have an opening to say, "Now perhaps
you would like to try a storage method that can do even more for you."
Perhaps that is the time to suggest a metal drum or a mud silo.
You know from your work that change seems to be accepted very slowly. It
is good to keep in mind the fact that for a farmer who has always done
things the same way, adding a small amount of insecticide to a sack of
grain is a large change. It is very easy to give people more than they
want or are ready to receive.
This section of the manual brings together all the grain storage information
which was introduced earlier:
* It discusses and shows some traditional storage methods
and gives specific directions for improving these methods.
Some of these methods are sack, basket, and pit storage.
* It gives plans for, among others, mudblock, ferrocement,
oil-drum and cement-stave silos.
* It describes other storage possibilities to give some
idea of the range of methods in use.
This section, together with the earlier parts of the manual, ought to help
you to help farmers define their choices. To provide even more information,
there are some valuable appendices to the manual:
STORAGE PRINCIPLES
Whichever kind of storage method a farmer uses, there are certain principles
upon which every method is based. Every storage container, no matter what
it looks like or what it is made of, should:
* keep grain cool and dry.
* protect grain from insects.
* protect grain from rodents.
All storage methods try to do the above three things. But to do these
things requires the following good storage practices:
1. Drying grain well (to 12-13% moisture content) before
putting it into storage.
2. Putting clean grain only into containers which have had
all old grain, dust, straw, and insects removed.
3. Keeping the grain cool and protected from large changes
in outside temperatures. This can be done in a number
of ways -- by using building materials which do not easily
pass on changes in outside temperatures to the stored grain,
by keeping or building storage containers away from direct
sunlight, by painting the containers white.
4. Protecting the grain from insects by following rules for
cleanliness and drying, by applying insecticide and/or by
putting the grain into airtight storage.
5. Waterproofing the buildings and containers as much as possible.
This is done both by the way the building is constructed
and by applying materials which keep water from soaking into
the building material. Storage buildings should be built on
well-drained locations. They should not be placed where they
will be flooded by ground water run-off during heavy rains.
6. Making sure containers are rodent-proofed in all possible ways.
7. Checking the grain regularly while it is in storage to
make sure it is not infested, and following recleaning
instructions to destroy insects, if they are found when
the grain is checked.
A farmer who has these seven points firmly in mind will know why a
particular silo or storage method has been built or changed in a certain
way. And he can then do much to improve his own storage facility by
applying the knowledge to his own problems.
The ideas and suggestions for storage methods which follow in this section,
no matter how different they look, all require that these seven steps
be taken if they are to be successful.
FINDING A GOOD STORAGE PLACE
SCRIPT # 1
Suggested Use: This script and the one which follows contain some
of the important points to remember about finding,
cleaning, and repairing storage places. VITA Volunteer
artist Guy T. Welch has provided illustrations
of some of these points to give some ideas on ways
this material can be presented through pictures.
* Rats, mice, birds, insects,and mold destroy a lot of
grain. It is not easy to keep these dangers away from
your grain. But you can do a lot to keep them away.
* Fix a good place to put your grain before you bring
it from the field.
* The place for grain storage is very important. Grain
storage places must be built on well-drained ground,
so the building or container does not get flooded
or take on too much moisture from the ground.
* Most insects and molds like warm, wet places.
* A good storage place is cool and dry.
* Grain storage is easier if you live in a cool, dry
land. Grains are easier to protect.
* But insects and rodents can attack even in these
places. Farmers must protect the grain from these
pests wherever they live.
* Some farmers store grain in large clay jars with
thick walls.
* Some farmers use metal drums for grain storage.
* Some farmers in warm places put grain in buildings
with thick mud, plaster, cement, or thatched walls
and roofs. Thick walls help to keep the hot air out.
Thick walls help to keep the grain cool.
* Some farmers store grain under the ground. Grain
stored under the ground is kept cool by the earth.
* You can put grain storage containers or jars on rocks
or wood. This keeps the containers off the ground.
Air can get under the container. This air cools the
grain.
* You can build storage rooms or buildings on posts.
This keeps the floor off the ground. Water from the
earth can not get the floor wet. Air can pass under
the storage building to cool the grain.
* There are many ways to store grain.
* Remember that the storage place must keep grain cool
and dry.
* Remember that the storage place must be clean and free
of insects and rodents.
* Your extension worker can help you find a way to store
grain that is good for you.
<FIGURE 2>
51cp05.gif (437x437)
51cp06.gif (486x486)
51cp07.gif (600x600)
51cp08.gif (486x486)
51cp09.gif (486x486)
<FIGURE 3>
<FIGURE 4>
<FIGURE 5>
<FIGURE 6>
CLEANING AND REPAIRING YOUR STORAGE PLACE
SCRIPT # 2
* Your storage room or building must be clean. Insects
live and have families in dirty places. Rats, mice,
and other pests like dirty places too.
* Take away and burn or compost all dust, old pieces of
grain, dirt, straw, and chaff from the storage place.
* There should be no cracks and holes in the floor,
ceiling,or walls. Insects and rodents use these holes
to get in.
* Fill and seal all cracks and holes.
* Seal large holes in wooden storage places with sheet
metal, flattened tin cans, or pieces of wood.
Concrete and plaster make good sealing material for
plaster, brick,and concrete buildings.
* Put paint or whitewash on the walls and floors of the
storage area. This paint helps close up very small
holes. Insects like these small holes.
* Do not use any poison until you talk to your extension
worker.
* Put mesh wire over large openings and windows. This
will keep out rats, chickens, and birds.
* The roof must keep rain from coming in. The grain
must be kept dry.
* Mend all holes and openings in the roof.
* Clean the outside area around the storage place.
* Clean out the containers that you put the grain in.
* Bags or sacks for storing grain must be shaken.
* Bags or sacks should be boiled in hot water and dried
in the sun. Mend any holes you find in the bags.
* Check with an extension worker for information on
poisons to kill insects and rodents.
* The extension worker will know what poison to use. He
will know how to use the poison.
* Always remember that many poisons can kill animals and
people.
* Use insecticide on the inside and outside of your
storage area.
* Put insecticide on all cracks and small places where
insects like to live.
* Put out traps for rodents.
* A good storage place is free of insects and rodents.
It is clean and dry.
<FIGURE 7>
51cp12.gif (486x486)
51cp13.gif (486x486)
51cp14.gif (486x486)
51cp15.gif (486x486)
51cp16.gif (486x486)
<FIGURE 8>
<FIGURE 9>
<FIGURE 10>
<FIGURE 11>
STORING GRAIN IN BASKET GRANARIES
Grain has been stored in basket-like containers made of grass, reeds,
bamboo strips, or small branches for thousands of years. The particular
building material depends upon the plants available near a farmer.
These basket granaries are so traditional and widely used that it does
not seem necessary to include a plan for making them. There are almost
as many different kinds of baskets as there are villages making them,
and the skills for this kind of work are passed on within families.
What this manual will present is some suggestions for improving basket
granaries so that grain stored in them is more protected from insects
and molds.
To increase the protection of grain kept in baskets:
* Keep the basket off the ground. Make a strong platform
upon which the basket can sit. The shape of the platform
will depend upon the shape of the basket. Putting
the basket on a platform prevents moisture from coming
through the ground into the basket. The platform also
offers more protection from rodents.
<FIGURE 12>
51cp17.gif (486x486)
* Make sure the basket is well-protected from the rain.
If it is a grass or reed basket, keep it in the house
or some other dry building. If it is woven of material
which can be kept outside, make sure the roof thatch
does not let any rain into the grain.
* Place rodent baffles (guards) on the legs of platforms
which support the baskets. These prevent rodents
from climbing or jumping into the baskets. (The rodent
proofing section contains information on making rat
baffles.)
* A tin can, with a plastic-cover that can be put on and
taken off easily, makes a good emptying chute (see
the picture below). Cut the bottom out of the can and
fit the open end of the can into the lower part of
the basket. This makes it unnecessary to take off
the cover each time grain is taken out.
* Baskets can be plastered inside and outside with
mud, clay, or cow dung. Covers should be tight and
sealed with plaster of the same material. It is
important for farmers to realize that grain holding
a lot of moisture, whether threshed or freshly
harvested, should not be placed in baskets which
have been plastered in this way. Plastering makes
the basket much more airtight. Moist grain needs to
have air passing through to dry it. If moist grain
is put into storage without enough air, it will mold
and rot quickly.
<FIGURE 13>
51cp18.gif (540x540)
INSTRUCTION SHEET FOR STORING GRAIN IN BASKETS
This instruction sheet includes some directions for using insecticide
in basket storage. You should include the names of insecticides available
in your area which are appropriate for use with grain being stored
in baskets. (Malathion and Pyrethrum are mentioned.)
You may want to use the information to make two instruction sheets:
one explaining good basket storage without insecticide; the other,
with use of insecticide. Also, you may want to illustrate the sheets
if you hand them out to farmers in your area who use basket granaries.
<FIGURE 14>
51cp19.gif (486x486)
CLEAN THE BASKET AND THE AREA:
* Make sure the area around the basket is clean. Baskets
should always be kept inside a building unless the
baskets have been built for outside use.
* Place the basket on a platform so that it will not
pick up moisture from the ground.
* Clean out all grain dust and broken grains if the
basket has been used before.
* Mend any holes in the basket.
* Plaster basket with mud, clay, or cow dung if storing
very dry grain.
CLEAN AND DRY THE GRAIN CAREFULLY.
IF YOU HAVE INSECTICIDE:
* Dust the inside of the basket with insecticide. Do
this carefully so any insects will be killed.
* Mix the dry grain with insecticide before you put it
into the basket. To mix the grain and insecticide,
you must:
Place the dry grain on a plastic sheet, clean floor,
or hard-packed ground.
Sprinkle insecticide over the grain. Use 1 packet
(4 oz.) of Malathion or pyrethrum dust for each 100
kg of grain.
Mix the grain and insecticide with a shovel until
they are mixed very well.
IF YOU DO NOT HAVE INSECTICIDE:
* Mix burned cow dung or wood ashes with the grain.
PUT THE GRAIN INTO THE BASKET. MAKE SURE THE COVER FITS TIGHTLY.
OPEN THE BASKET AND CHECK THE GRAIN EVERY TWO MONTHS. IF YOU FIND
INSECTS:
* Winnow, sieve, or place the grain in the sun.
* Clean the basket.
* Add more insecticide or ashes.
* Put the grain back and replace the cover tightly.
WHEN YOU REMOVE THE GRAIN FOR FOOD, WASH IT CAREFULLY. INSECTICIDES
CAN LEAVE MATERIAL ON THE GRAINS WHICH IS NOT GOOD FOR PEOPLE TO EAT.
STORING GRAIN IN SACKS
Putting grain in sacks (bags) is a very old
method of storing. Storage sacks are made
of woven jute, hemp, sisal, local grasses,
cotton -- whatever material is available
in the area. Sacks are relatively expensive
as they do not often last for more
than two seasons. Sacks do not give a lot
of natural protection against insects,
rodents, and moisture. But sack storage
has some advantages for the small farmer,
and there are things farmers can do to
protect their sacked grain.
<FIGURE 15>
51cp21a.gif (317x317)
The Advantages of Sack Storage for Farmers:
* Grain stored in sacks made of fibers can have a little
higher moisture content than grain put into airtight
storage. If the sacks are properly stacked, air can
move through the sacks to dry and cool the grain.
<FIGURE 16>
51cp21b.gif (437x437)
* Sacks are easy to label. Farmers can label old
grain sacks and new grain sacks to keep them
separate. Seed grain can be marked and kept
separately from the other grains.
* Sacks are easy to move around. And sacks or
parts of sacks can be used as they are needed.
* Sacks can be stored in a farmer's house - no special
buildings or containers are needed.
* Farmers in a village may decide to build a shed
to hold the grain belonging to all the village's
farmers. It is easy to mark sacks so that each
farmer's grain can be found simply.
Grain stored in fiber sacks is easily attacked by insects, rodents,
and molds. Often these attacks are worse because a farmer has no
all he can to protect his grain sacks.
CONTROLLING MOISTURE AND PREVENTING MOLDING IN SACKED GRAIN
* Dry the grain well. Although grain can contain
about two percent (2%) more moisture for sack
storage than for airtight storage, the grain should
be as dry as possible.
Check the grain every two weeks. Suggest to the
farmer that he make checking his grain part of a
weekly or bi-weekly routine. Put his hand into
a sack of grain to check for heating. He can
smell the grain and look for dark kernels: signs
of mold. If these signs are found, he should
dump out the grain and dry it again.
* Waterproof the walls and roof of the building where
the grain is stored.
STACK THE SACKS ON PLATFORMS RAISED OFF THE FLOOR.
This keeps sacked grain from taking moisture from
the floor. Farmers can make these platforms out
of whatever materials they have. If no wood or
bricks are available to make a platform, the
ground can be covered with plastic sheets. The
raised platform is better than the plastic because
it also allows air to flow under the sacked grain.
<FIGURE 17>
51cp22.gif (486x486)
* Stack the sacks in a neat manner. Leave space between
the sacks so that air can move freely between the
sacks.
<FIGURE 18>
51cp23a.gif (486x486)
CONTROLLING INSECT ATTACKS ON SACKED GRAIN
* Mend cracks in the walls, roof,
and doors of the building where
grain is kept. This mending
keeps insects from getting in
and out of the building through
the cracks.
<FIGURE 19>
51cp23b.gif (353x353)
* Remove and check sacks of grain
left from the last harvest. The
farmer should take them outside
before he cleans the storeroom.
This grain should be winnowed,
sieved, and spread out in the
sun for a time before it is put
back into the bags. If the rain
is seived, light a fire and burn all the insects found, so they
will not move right back into the grain.
* Clean the room well before placing
the sacks inside. Make sure there
is no dust, dirt, and old grain left.
Sweep walls and ceilings as well as
the floors. Some farmers may want
to burn a small, smoky fire in the
room to drive out insects, if they
are not going to use insecticide to
protect the inside of the building.
<FIGURE 20>
51cp23c.gif (317x317)
If Insecticide Is Available
* Apply insecticide to the storage building. You can recommend
DDT, Malathion, and Lindane for use on buildings and
instruct the farmer on use of these three poisons. There
also are other insecticides that can be used on buildings.
* Dust insecticide on the sacks before the grain is put in.
(Or the insecticide can be put on the bags as they are
stacked. There is a page attached to the end of this section
which gives instructions on applying insecticides
as you stack grain.) Malathion is a safe insecticide
for a farmer to use for this purpose -- it is safe
for him to use and safe for his grain. Brush the sacks
with a stiff brush and then shake them well. Brush
both the outside and the inside of the sack. Put
Malathion on both the inside and the outside of the
sack.
* Mix the grain with insecticide before it is placed in
bags. Use only clean, dry grain. See the end of this
section for instructions on mixing grain and insecticide
for sack storage.
If Insecticide Is Not Used
* Clean the sacks carefully. Shake the sacks well. If
sacks are made of a material which can be placed in
hot water, boil the sacks or dip them in very hot
water. Dry the sacks in the hot sun. If sacks can
not be placed in water, brush them well and place them
in the sun. Make sure both the inside and the outside
get exposed to the sun.
<FIGURE 21>
51cp24.gif (382x528)
* Use only clean, dry grain. The grain should be checked.
It should be free of insects (the easily seen adults,
at least).
* Mix ash from cattle dung or wood or fine sand with the
grain if insecticide is not to be used. Use one, 10-liter
bucket of ash for each 100kg of grain.
* Stack the sacks carefully (as shown earlier). The platform
holding the sacks must be placed away from the walls
because there are insects which live in wood and thatch
which will move to the stored grain.
<FIGURE 22>
51cp25a.gif (437x437)
* Check the grain regularly. If no insecticide has been used,
a farmer may have to dump the grain out, get the insects out,
and re-bag the grain every two months or so. If Malathion is
used, that insecticide possibly will have to be reapplied after
four months of storage.
CONTROLLING RODENT ATTACKS ON SACKED GRAIN
* Keep the area around the sacks clear of dirt,
broken grains, grain dust, and trash. This clearing
makes it harder for rats and mice to find home and
food near the stored grain.
<FIGURE 23>
51cp25b.gif (486x486)
-- Cover and repair holes that rodents might use to get
into the building where the grain is stored.
-- Keep the sacks off the floor. This does not stop
rats and mice from attacking the grain. but it does
make cleaning, poisoning and baiting, and looking
for rats and mice easier.
-- Move the stacks if rodents are seen. Then use traps
and poisoned baits near the pathways and rodent holes.
(See the section on rodent control for more information
on using traps and poisons to control rodents).
<FIGURE 24>
51cp26.gif (393x393)
KEY POINTS FOR SUCCESSFUL SACK STORAGE
* Sacks and buildings which are clean.
* Dry grain which is free of insects.
* Good shelter which keeps out rain, insects, rodents,
and birds.
* Careful checking of the grain while it is in storage.
The following pages include:
* Instructions which can be given to farmers to aid them with
mixing grain and insecticides for sack and small-container
storage.
* Instructions for adding insecticide while stacking layers
of grain bags.
* Sample material for a leaflet which could be made to
illustrate proper sack storage through pictures.
MIXING GRAIN AND INSECTICIDES
FOR SACK AND SMALL-CONTAINER STORAGE
The following insecticides and dosages are recommended for direct mixing
with grain:
-- Malathion. Use 120 grams of 1.0% dust for each 200kg
of grain.
-- Lindane. Use 120 grams of 0.1% dust for each 200kg of
grain.
-- pyrethrum. Use 120 grams of 0.2% pyrethrins plus 1.0%
piperonyl butoxide dust for each 200kg of
grain.
If you can find Malathion, for example, only in 2%, 5%, or .5% mixtures,
you will have to adjust the strength of the insecticide. For example,
if you are using 2.0% Dust,you need to use only 60 grams of 2.0% Dust
per 200kg.
* Apply the insecticide to one half sack of grain at a
time.
* Empty one half of the grain from a sack onto hard-packed
earth, a plastic sheet, or clean floor.
* Put 60 grams of insecticide dust on the grain.
* Turn the grain over and over with a shovel. Make sure
the grain and insecticide are well-mixed.
* Empty the other half of the sack on top of the grain you
have just mixed.
* Put the rest (the other half -- 60 grams) of the insecticide
on the grain.
* Mix very well.
* Put the grain back into the sack and close it tightly.
REMEMBER: THE GRAIN MUST BE DRY BEFORE THE INSECTICIDE CAN BE USED.
INSECTICIDES DO NOT WORK AS WELL IF THE GRAIN IS TOO MOIST.
TREATING STACKS OF SACKED GRAIN
RECOMMENDED INSECTICIDES AND DOSAGES
There are two ways to apply insecticide to stacks of sacked grain:
1. Layer by Layer
Spray or dust each layer of sacks with Malathion or Lindane
as the stack is being built.
Malathion -- 25 grams of 2.0% Dust per sack
or
50 grams of 2.0% Dust per square meter
Lindane -- 25 grams of 0.5% Dust per sack
or
50 grams of 0.5% Dust per square meter
2. Stack Treatment
Build the stack first. Then spray all four sides and the top
surface of the stack. Use Dispersible Powder formulations of
Malathion and Lindane at the dosages recommended for spraying
storage buildings.
When this treatment is finished, apply a band of insecticide around the
bottoms of the stacks to control crawling insects. Malathion is best
for this job, though where it is not available, Lindane or DDT may be used.
STORING GRAIN IN SACKS
Suggested Uses: This is an easy-to-read summary of the important
things to remember for good sack storage. Pick out
the points that best fit your situation and use them
with farmers in your area. They are simply worded
and can easily be pictured by using drawings or photographs;
they can be translated easily.
* Grain is often stored in sacks. Sacks are also called bags.
* Sacks are made of different things.
* Sacks are easy to put away. You can store them in a corner
of the house.
* You can put grain sacks in a special storage building.
* Sacks are easy to carry.
* Each sack can be labeled to show what is inside.
* Put your name on each sack. It is easy to show which grain
belongs to you.
* Insects, rats, and molds can attack grain kept in sacks.
* You can protect the sacks from these dangers. You must start
before the grain goes into the sack.
* Clean your storage area well.
* Make sure there is no dust, old grain, straw, or trash in
the storage place.
* Mend holes in the roof, floor, or walls.
* Check for cracks. Insects hide there.
* Make sure rain and water from the ground can not get the
grain wet.
* Put rat guards on the legs of storage containers or buildings.
* Ask your extension agent about insecticides you can use.
* Shake out old storage sacks.
* Put old sacks in boiling water, if possible.
* Dry old sacks in bright sunlight.
* Mend holes in the sacks.
* Spray or dust the sacks with insecticide.
* Spray or dust the building with insecticide.
* Make sure the grain you put into the sack has no
insects in it.
* Put only clean, dry grain into sacks.
* Some insect poisons can be put into the sack with the
grain. This protects the grain from insects for some
time. Ask your extension agent before you do this.
Some poisons can poison the grain.
* You can add sand and ash to the grain in the sack.
Insects do not like these materials.
* Poison is better than sand and ash. But sand and
ash are better than putting the grain in with no
protection.
* Close all sacks tightly.
* Put each kind of grain in a separate sack.
* Place grain sacks off the ground.
* If you have many sacks, stack the sacks well. Leave
room between the sacks. Air in the room will cool
the grain better if there is room between the sacks.
* Do not stack sacks against the walls. Insects and
termites get into the grain from the walls.
* Check the sacks often. Look for insects. Smell for
mold. Look for wet places.
* If you find insects or mold, dump the grain out of
the sack and leave it in the sun. Sieve the grain.
* Clean the sacks again.
* Put the grain back into the sacks immediately after
cleaning.
REMEMBER: THERE ARE POISONS WHICH YOU CAN ADD TO THE SACKS OF GRAIN
AND OTHERS WHICH ARE TO BE USED ONLY ON NON-FOOD LIKE
COTTON.
THESE POISONS CAN BE DANGEROUS.
DO NOT USE POISON BEFORE YOU TALK WITH YOUR EXTENSION
WORKER.
AIRTIGHT STORAGE
INTRODUCTION
Insects can still grow and reproduce in very dry grain. Grain dried to
a 12 or 13% moisture level will not mold, but can still be very good food
for insects.
The moisture level in grain has to be 9% or less to slow down insect
development. Very high and very low temperatures also slow down insect
growth. But most farmers will have trouble getting their grain below
12% moisture and in using temperature to control insect development.
They often do not have the special equipment necessary to do these things.
More and more farmers do use insecticides to control insects in grain.
But some insecticides are dangerous; some are expensive; sometimes they
are not available; and there is increasing concern about using chemicals
of any kind on food products.
HOW IT WORKS
Airtight storage simply means putting grain into containers which keep
air from getting into the grain. Some air is let into the container at
the time the grain is put into storage. But after the container is sealed,
no more air enters. The respiration of the grain and any insects in it
uses up all the oxygen. Insects need oxygen to live. They die without
it. Any molds present which require oxygen also will die.
You can show farmers how airtight storage works by putting
some insects and grains on a very smooth surface and
turning a glass over on top of them. Make sure the glass
is tight against the surface. Seal it with wax or some
other material. Or seal some grain kernels and insects in
a glass jar. Cover the jar with a screw-on lid or a
plastic sheet. Just make sure no air can enter the container!
Wait for a while. The insects will begin to move more
slowly. Finally, they will die. How long it takes for
the insects to die will depend upon the number of insects,
the amount of grain, and the size of the glass container.
You can speed up the experiment by placing a lighted
candle under the glass container. The flame on the
candle requires oxygen to keep burning. The flame
will use up the oxygen in the container quickly.
When the oxygen is gone, the flame will go out. Soon,
the insects will die.
The lack of oxygen, which kills insects, does not seem to hurt the
grain or to keep seed grain from germinating when it is planted.
Successful airtight storage depends upon a number of things:
* Building containers which are airtight. This
means using materials which do not let air flow
through them, for example, metal, plastic, concrete.
These containers must be checked to make
sure there are no cracks or holes. Sometimes a
farmer will see light coming through cracks in a
large container. If the container is a gourd,
for example, he can check for cracks by filling it
with water to see if there are any leaks. All
cracks in storage containers should be sealed
for good protection. In addition, it is usually
a good idea to coat or paint the entire outside
(and sometimes the inside) surface of the container
with tar or oil-based paints (they are
waterproof and also do not let air pass through).
For a farmer who cannot afford to buy these materials,
there may be local trees and plants
which produce materials useful for waterproofing.
* Sealing tightly the holes for putting grain into
the container and for taking grain out. Tar, wax,
or pieces of rubber cut from old tires, and inner
tubes can be used for this.
* Filling airtight storage containers to the top
is important. Full containers, which are sealed
against air, can kill insects in a few days. But
if the container is not full, the insects take a
lot longer to die. And before they die, they may
damage a lot of grain.
* Keeping the storage container closed. Unless the
airtight container is quite small, farmers probably
will want to store the grain they use for food
separately. The storage container holding the food
grain is opened often. Every time a container is
opened, more air containing oxygen enters the
stored grain. This added air and frequent opening
encourages insect growth.
Some of the storage methods used for thousands of years have been based
loosely on the principles of airtight storage. A farmer might not call
his method airtight storage, or be able to tell you why it works. He
stores his grain this way because it keeps his grain pretty safe, and he
has been doing it this way for many years. Many of these methods are
basically good. Improvements can make them more airtight and, therefore,
increase their ability to protect grain.
CHOOSING A METHOD OF AIRTIGHT STORAGE
A farmer has to decide what he needs his storage method to do, and, then,
he must figure the costs of each method. Some of the methods, such as
metal drums and plastic sacks, cost more money. But they are definitely
airtight when used correctly and are very likely to make up their costs
by good storage of grain. Other methods, such as the Improved Mudblock
Silo, are harder to make airtight, take longer to build, and require more
upkeep. But they can hold large amounts of grain, and they can be made
with local materials.
Airtight storage is something farmers who store dry grain should work
toward. (REMEMBER: IF THE FARMER IS STORING GRAIN WHICH HAS A MOISTURE
CONTENT OVER 12-13%, HE SHOULD NOT USE AIRTIGHT STORAGE. Grain which has
a high moisture content should be stored so that air can pass over the
kernels.)
The rest of the material included in this section describes storage
methods which are quite airtight and waterproof or can be made so by
making the various improvements described here. This material should
serve as a useful guide to some of the storage possibilities that are
available to small-scale farmers.
STORING IN GOURDS AND BASKETS
Gourds are the hard, dried outside cases (skins) of certain fruits or vegetables
(they are members of the squash family). They are found in many
places and are used for storing small amounts of grain. Grain for planting
is often stored in gourds.
Scientists are working to discover ways of making gourds effective airtight
containers for grain that has no more than 12-13% moisture in it. Here
are some of the findings:
* Linseed oil or varnish painted all
over the outside of the gourd
makes it almost airtight.
* The stopper or cover for the gourd
has to be sealed well.
* Pitch and bitumen are easier for
farmers to get and seem to make the
gourds airtight.
* Any thick substance which will stick
to the gourd will work very well.
There are probably local materials
which can be found and made to seal
the gourd. It is likely that some
of the materials found for waterproofing
soil would be useful
to seal the gourds. If the
material stays sticky and does
not dry, sprinkle sand or earth all
over it.
<FIGURE 25>
51cp34.gif (317x317)
If gourd-shaped vessels made of clay or other local materials are available
in your area, perhaps these can be made airtight in the same way.
Baskets made of local materials also can be made more airtight. Cover the
baskets inside and out with mud plaster. Make sure the cover closes
tightly. The outside of the basket can then be coated with a waterproofing
or sealing-material.
Possible advantages: Disadvantages:
* Useful for storing seed grain * Gourds do not hold large amounts
and smaller quantities for food. of grain.
* Easy to get to the grain and to
check for insects.
* Easy to label, so the farmer knows what
kind of grain is in each container.
STORING GRAIN IN UNDERGROUND PITS
Farmers store grain in underground pits (holes) in many parts of the world.
Pits are used for storing threshed sorghum and maize. They also are used
for wheat, peas, and beans. In areas where pit storage is used, it has
served farmers well as a way of avoiding theft of the grain (because the
pits are hidden). Also, because the pits are dug deep into the earth, they
keep the grain cool. In addition, some pits are relatively airtight.
However, pit storage is generally not a storage method to encourage a
farmer to adopt. If a farmer is looking for a storage method, he is more
likely to get airtight storage by using oil drums, plastic sacks, etc.
<FIGURE 26>
51cp35.gif (393x393)
DRY PITS
There are many, many kinds of pits. The pits themselves are not always
airtight or waterproof. Therefore, some farmers line the pits with straw
to absorb moisture from the earth or from leaks in the covers. The
straw gets damp and becomes moldy. These molds use up any air in the
storage pit, so that any insects present in the grain die. Often in
underground storage pits, the grain at the top and around the sides of
the pit is moldy. The main part of the grain, however, stores well.
WET PITS
In some areas, farmers build wet pits. During the rainy season,,the water
in the ground may rise right into the pit. The grain in this case is full
of water. But the grain respires more quickly when wet and uses up the
oxygen. Insects and molds requiring oxygen die. Often these wet pits
are built where cattle are kept because cow dung uses up oxygen as it
decomposes. The grain kept in wet pits may ferment (sour) and thus is
not good for seed. But often it seems to store better than grain kept
in drier pits.
IMPROVING PITS
The question to keep in mind here is whether or not an improvement in
the traditional pit is wise or necessary. A farmer who does not open his
pit often may have very light losses from insects and molds. In this
case, making improvements may not be necessary.
However, in areas where farmers have lost a lot of grain stored in pits
due to insects and molds, it may be a good idea to offer several suggestions
for improving the pit storage. Pit storage can be made more safe by improving
the covers, building shelters over the pits,,or by using a lining
in the pits.
Replacing Covers
Pit storage usually can be improved by replacing wood and mud covers with
metal or plastic covers.
* Use one large sheet of metal or plastic to cover the entire
area.
* Make a hole in the middle of the large sheet. This is,so grain
can be taken out. Cover the smaller hole with a piece of
of the same material.
* Seal the entire cover with a mixture of mud or dung or with
bitumen.
Building Shelters
Some farmers build shelters over the pit stores. The shelters should be
movable so that when the sun is shining, the pit can be exposed for drying.
The shelter should be used when it rains. The problem with this type of
shelter is that the farmer cannot keep the place of the pit a secret and
the grain may be taken by thieves.
Improving Pit Linings
The other area where pits can be improved is the lining used in the pit.
Straw and Mat Lining
* Put down a layer of straw on the pit floor. Cover the
straw with mats made from bamboo or local grasses.
* Line the walls with straw and matting as well.
* Pour in dry grain to the top of the lining.
* Continue placing the lining and pouring the grain until
the pit is full.
<FIGURE 27>
51cp37a.gif (600x600)
Advantages: Uses local material and costs nothing.
Stores grain much better than an unlined pit.
Disadvantages: Does not protect the grain as well as the following
methods.
Plastic Bags
* Place very dry grain in
plastic sacks.
* Seal tightly as shown.
* Store sacks in the pit.
* Seal the pit well.
<FIGURE 28>
51cp37b.gif (486x486)
Advantages:
Airtight if the bags are well
sealed.
A farmer can remove part of the grain
easily without letting air and
moisture into the rest of the grain.
Disadvantages:
May be expensive or hard-to-get.
Plastic Lining
* Line the pit with large plastic sheets or with plastic bags cut
open to make sheets.
* Make sure the edges of the plastic sheet lie over each other.
* Fill the pit with clean, dry grain and seal tightly.
Advantages: Gives good protection from moisture if the
plastic is sealed.
Disadvantages: Can be damaged easily.
Plastic may be expensive, unavailable, and
hard to replace.
Using Plastic Lining and Plastic Bags in Large Pits
* Lay plastic sheets or cut-open plastic bags on the floor.
* Fill a number of plastic bags with very dry grain and put these
against the sides of the pit.
* Pour dry grain into the space between the floor and the tops
of the sacks.
* Put another layer of filled plastic sacks against the walls
on top of the sacks already in the pit.
* Fill the space with grain.
* Continue placing plastic sacks against the sides and pouring
in grain until the pit is full.
* Cover the top of the grain with plastic.
* Seal the pit
<FIGURE 29>
51cp38.gif (540x540)
Advantages: Keeps most of the grain
very well.
Stores large amounts of
grain.
Disadvantages:
May be hard to find
plastic.
May be expensive.
Loses some grain because
it falls down between the
bags and the walls of the
pit.
Concrete Linings
There has been work done on various concrete linings for underground pits.
Because this method requires more labor, material and money, it is not
as easy for a small farmer to use. However, it will be outlined in more
detail in the part of this manual which discusses ferrocement.
STORING GRAIN IN PLASTIC SACKS
Plastic bags make good airtight storage containers.
* Use plastic bags which are .20 to .25mm thick (500-700 gauge).
* Make sure there are no holes in the plastic. Even the
smallest hole will cause problems.
* Some insects can puncture plastic when trying to escape from
the sack. But this can be stopped by putting a cloth bag
of tightly woven cotton inside the plastic bag. The
cloth is added protection.
* Use grain which is very dry.
* Add insecticide to the grain. It can take a week or more
for insects to use up the oxygen which is in the bag.
* Fill the sacks and seal them tightly.
* Store the filled bags off the ground on a smooth surface so
that they will not be punctured by the floor or anything
sharp.
Advantages: Plastic bags are easy to store.
Plastic bags are easy to move around.
They provide good protection against insects.
Plastic bags make good containers for fumigating
small quantities of grain.
Disadvantages: Plastic can be torn or punctured easily.
They are generally good for only one year
and must be replaced after that because
small holes have been made in them.
Rodents can eat through plastic.
Plastic bags are expensive in some area.
The following leaflet, prepared by VITA artist Ken Lloyd is designed to
show farmers a good procedure for storing dry grain in plastic sacks.
<FIGURE 30>
51cp40.gif (600x600)
51cp41.gif (600x600)
51cp42.gif (600x600)
<FIGURE 31>
<FIGURE 32>
STORING GRAIN IN METAL DRUMS
In many parts of the world, 220-litre oil drums
are available and not too expensive. If farmers
in your area can find oil drums, this is a
storage method which may be a good improvement.
Sorghum, maize, millet, cowpeas, and groundnuts
are among the materials which can be stored
successfully in these drums. The grain should
be dry (12% moisture or less) when it is put
into the drum.
<FIGURE 33>
51cp43.gif (317x317)
Here is the procedure for using a drum:
* Make sure the drum is clean and dry inside.
* Check for holes. Holes in these drums can be plugged
with wax.
* Pour clean, dry grain into the drum through the small
top opening. Use a wide-mouth funnel to help with
this job.
* Shake the drum to let the grain settle; then fill it
again.
* Make sure the drum is full.
* Screw the cap on tightly. If the rubber ring on the
inside of the cap is missing, smear the cap with grease.
Each drum holds about 660kg of grain.
Advantages: Provides good airtight storage control of insects.
Protects the grain from rodents.
Works well for seed grain; does not seem to hurt
the ability of the seed to germinate.
Is available in most areas and is not expensive.
Makes a good container to fumigate grain in.
Disadvantages: Has a small opening for filling and emptying.
Special clamp-on lid is sometimes available.
But this lid does not create airtight conditions
and insecticides must be used.
Works best when grain is being stored 5 months
or more.
Has to be kept out of sunlight to prevent
moisture changes and heating in the stored
grain.
Can rust and must be repaired carefully for
airtight storage to be continued.
<FIGURE 34>
51cp44.gif (317x317)
STORING GRAIN IN METAL BINS
Metal bins are being tried for small-scale use in many parts of the world.
In some areas, farmers can buy metal bins in different sizes. They are
sometimes expensive, and they rust in moist areas. Often a farmer needs
to be a member of a credit program to get the money to buy this type of
metal silo or bin. Then he repays the money for the cost of the bin. Hopefully,
the bin pays for itself by reducing losses to the stored grain due
to attacks by insects and rodents.
Metal bins can also be built quite easily: but the farmer must know how
to weld and work with metal. Or someone with these skills must be able
to help.
CHARACTERISTICS OF METAL BINS
* Built above the ground -- either
on platforms or on
cement bases when kept outside.
The metal bottoms will
rust because of contact with
ground water if the bins are
on the ground.
* Rounded in shape to hold the
pressure of the grain better:
a square bin would have more
seams and be more likely to
break open.
* Painted white or stored out of
the sun because metal conducts
(passes on) heat very well.
<FIGURE 35>
51cp45.gif (486x486)
Advantages of Metal Bins
* Good control of insects, molds, and rodents if bins are well-made,
well-sealed, kept off the ground, and out of the sun.
* Small metal bins are lightweight and may be moved easily.
* A metal bin may pay for itself out of the farmer's increased
profit. This is true (for all improved storage methods) only
where initial costs are not too high or a good credit program
is available.
Disadvantages of Metal Bins
* Metal sheets for building the silo are more expensive than
most locally available materials, or, in some areas, cement.
* Construction of a bin requires special equipment to cut and
weld the metal and people trained in working with metal.
* Metal rusts quickly in hot, wet places. Sheet metal for bins
must be galvanized or painted regularly to protect the metal
from rusting. This is another cost to the farmer.
Blacksmiths and people with metal-working experience, who might be interested
in making bins to fit local needs,should be encouraged to try to do so.
Experimenting with various designs will give information which can help
you decide what kind of metal bin will work best in your area.
The following information on various metal bins is provided to give some
idea of what types of bins are available. Wherever possible, an address
is included so that you may write for further information.
CIRCULAR STEEL BIN
The bin shown here is very useful for storing small quantities of grain
indoors. It can be made in four sizes, ranging from 500kg to 3 tons.
The chart included here gives the dimensions for each size of circular
steel bin.
<FIGURE 36>
51cp46.gif (486x486)
Description
* Opens at the top for filling and has a spout at the bottom
for emptying.
* Has a flat top and bottom made of plain Mild Steel sheets.
* Has circular sides made of corrugated Mild Steel sheets.
* Comes in 4-6 pieces which can be put together on site. The
bin can be taken apart when not in use and put back together
when it is needed again.
* Prevents uneven temperatures within the bin by building-in
a special arrangement.
* Uses neoprene washers with bolts to make the bin airtight.
* May be used for fumigation, as required.
* Can be made in any small sheet-metal workshop.
* Stores grain to be used for seed safely.
Capacity Height (cm) Diameter (cm) Gauge Steel Sheet
500kg 125 80 28
1 ton 165 100 26
2 ton 210 124 24
3 ton 210 150 24
For further information on this and other bins which might be of use
to small farmers in your area, please write to:
The Grain Storage Research & Training Center
Department of Food
Government of India
Hapur, Uttar Pradesh
India
METAL BINS FOR HOME USE
A "Save Grain Campaign," begun in India in 1965, resulted in a number of
metal bins which were designed specially for use in the home and on a
small farm.
<FIGURE 37>
51cp48.gif (486x486)
Two styles of bins are pictured here. Each bin is pictured in two sizes.
The following chart shows how many kilograms of paddy, maize, or wheat
each size of bin can hold.
CAPACITY PADDY(*) MAIZE(**) WHEAT(***)
Cubic Meters kg kg kg
0.42 230 300 315
0.68 375 485 510
0.82 450 580 615
1.35 745 960 1015
(*) Approximately 550kg per cubic meter
(**) Approximately 710kg per cubic meter
(***) Approximately 750kg per cubic meter
The specifications and technical drawings for these bins are available
in booklet form from:
Save Grain Campaign
Ministry of Agriculture
Department of Food
Krishi Bhavan
New Delhi, India
SHEET METAL SILO
This silo was developed by the Institute of Tropical Agriculture Research
in Benin (formerly, Dahomey), Africa. It is a good example of an easily
made metal storage container.
The model below is made of sheet metal, 1mm thick, welded together at
the seams. It has two openings, one for filling at the top of the bin and
one for emptying at the bottom. The cost of the 3 ton model shown here
is about $175 (U.S. currency) when manufactured in small numbers.
<FIGURE 38>
51cp49.gif (540x540)
FUMIGATION OF SMALL QUANTITIES OF STORED GRAIN
Fumigants are insecticides in the form of gas. This gas can kill adult
insects living outside the grain kernels and larval stages living inside the
kernels. Once the gas disappears from the grain, there is no more protection
against insects.
BECAUSE FUMIGANTS ARE GASES, THEY MUST ONLY BE USED IN CONTAINERS THAT
WILL NOT LET ANY OF THE GAS GET OUT. THIS GAS CAN KILL HUMANS AND ANIMALS
AS WELL AS INSECTS.
<FIGURE 39>
51cp50a.gif (57x353)
The easiest and safest fumigant to use is Phostoxin. In many areas,
Phostoxin is relatively expensive. You can buy it in the form of tablets
or pellets. These formulations only start to turn into gas when they are
taken out of their containers and placed in the air. When the moisture
from the air touches the tablets, the gas begins to form. Phostoxin containers
must always be tightly sealed when not being used.
<FIGURE 40>
51cp50b.gif (200x600)
It is not a good idea for a farmer to use Phostoxin himself -- unless he has
used it before, and you are sure he understands the use of this fumigant.
But you should know how to use Phostoxin so that you can instruct and help
the farmer fumigate his grain.
So the following pages present fumigation procedures which will be most
helpful to the small-scale farmer: fumigation for stacked grain sacks;
fumigation in plastic bags; fumigation in small metal bins, silos, and
oil drums.
REMEMBER: WEAR GLOVES WHEN YOU USE PHOSTOXIN.
KNOW WHAT TO DO IN CASE OF AN ACCIDENT.
KEEP ALL PEOPLE AND ANIMALS AWAY FROM THE AREA WHERE
FUMIGATION IS BEING DONE.
FUMIGATING GRAIN IN PLASTIC BAGS
* Use 1 pellet of PHOSTOXIN for each 100kg of grain.
Tablets contain more poison than pellets; 5 pellets are equal
to 1 tablet. If you cannot find pellets, you can cut one tablet
in 4 pieces. Therefore, one tablet will fumigate 4 bags of grain.
CUTTING PHOSTOXIN TABLETS IS DANGEROUS AND MUST BE DONE VERY CAREFULLY.
You must be sure there are no little pieces of the tablets lying
around after you cut. If there are pieces, drop the pieces into
a large pail of water which has soap in it. Do this outside in
the open air. The gas will cause bubbling in the water. When
the bubbles disappear, you can throw the mixture away.
* Use heavy gauge (500 gauge) plastic bags.
* Make sure the bags have no holes or tears. Mend any holes with
tape.
* Fill a bag with grain.
* Put the pellet of Phostoxin in an unsealed envelope or piece of
paper and place the packet on top of the grain in the bag.
* Close the bag and tie as shown.
<FIGURE 41>
51cp51.gif (600x600)
* Place a warning on the bag so no one will touch or open the bag.
* Leave the bag as it is for at least 5 days. It is even better to
keep the grain in the bag tightly sealed until it is needed. Gas
cannot protect against new attack, but once fumigation has killed
any insects present, the plastic bag will maintain airtight storage
conditions which will control insects.
NOTE: PHOSTOXIN may be expensive and may not be available in all
areas. Check with your extension agent for information on
other insecticides which might be useful for you to use on
your stored grain.
FUMIGATING SACKED GRAIN UNDER PLASTIC SHEETS
* Use PHOSTOXIN.
3 tablets per 25 45kg bags or 1,125kg of sacked grain
OR
15 pellets per 25 45kg bags or 1,125kg of sacked grain.
* Use fumigation on bags made of jute or fiber. If using plastic
bags, make sure the bags are open before fumigation begins.
* Stack the sacks on the floor on a sheet of plastic, unless the
floor is concrete. Do not fumigate directly on the ground
because the soil will be temporarily poisoned by the fumigant.
If the fumigating is being done outside, stack the sacks on a
large sheet of plastic. Make sure the plastic is larger than
the grain stack on all sides.
* Take a 500 gauge plastic sheet. The sheet must be large enough
to cover the stack completely and be held to the ground tightly.
If necessary, you can overlap and tape smaller sheets together
to make a large enough sheet.
* Check the sheet to make sure there are no holes in it. You
can do this by holding it up to the light. Mend any holes or
tears with tape.
* Spread the right number of tablets around the sacks. Spread
the tablets around so that they do not touch each other.
* IMMEDIATELY COVER THE STACK WITH THE PLASTIC SHEET.
<FIGURE 42>
51cp53.gif (600x600)
* Make sure the edges of the sheet are sealed tightly. Use loose
sand, sand bags, poles, etc. to hold the sheet down.
* Keep the doors and windows open if you are fumigating inside
a building. (This is of course true only when you are fumigating
under a plastic sheet inside a building -- not when you
are fumigating an entire building. In this case, you would
want to close the doors and windows tightly.)
* Do not let anyone enter the fumigation area.
* Leave the stack under fumigation for at least 5 days. Some
PHOSTOXIN users prefer to remove the sheet while wearing a
gas mask. But a gas mask is not necessary, if you follow
these simple suggestions: lift the plastic sheet at one
corner using a long pole. This means that if there is any
gas still under the sheet, it will not hit you in the face
when you lift the cover. Leave the stack as it is, with
the one corner lifted up, for 1 or 2 hours.
* Remove the plastic sheet after 1 or 2 hours if there is
no strong smell.
NOTE: One characteristic of PHOSTOXIN which makes it relatively safe
for farmers to use is the very strong smell associated with
PHOSTOXIN. The smell, which starts being released almost
immediately, is a good warning to users because the smell is
noticeable before the gas reaches a poison strength which can
kill or hurt people.
FUMIGATING STORED GRAIN IN SMALL METAL
CONTAINERS OR SILOS
* Use 3 tablets or 12 pellets of PHOSTOXIN for-each 4,400kg.
* Make sure the emptying chute and filling holes are sealed. A
thick coating of grease will make a good seal.
* Check to make sure bolt holes and seams of a water-tank bin
are sealed. You can seal these with bitumen or melted wax if
you are not sure they are tight.
* If the grain level in the bin is no more than 6m, you can
spread the tablets only on top of the grain.
* Spread the tablets as you pour in the grain only if the grain
can be sealed up within 4 hours. Remember to place the tablets
in an open envelope. In a larger silo, you can build up the
grain to a level of 5m and then start putting in tablets.
Continue putting in grain and tablets until finished. Start
counting 4 hours from the time the first tablets are put in.
* Seal the manhole just as soon as all the grain and tablets are
inside.
* MAKE SURE THE MANHOLE IS TIGHTLY CLOSED. USE A THICK COATING
OF GREASE, WAX, OR CEMENT MORTAR TO SEAL IT.
* Leave the silo unopened for at least 5 days. If the grain is
not needed, keep the container sealed until the grain is
needed.
WARNING! YOU MUST HAVE THE MANHOLE SEALED WITHIN 3 or 4 HOURS OF
ADDING THE FIRST TABLET OF PHOSTOXIN. PHOSTOXIN GAS
CAN KILL.
NOTE: Metal drums are good containers in which to fumigate grain. Simply
drop in the correct number of pellets for the size drum, seal it
tightly,and wait for 5 days.
STORING IN EARTHEN STRUCTURES
Farmers for thousands of years have been storing grain in bins and other
containers made of clay. Earth is available and easy to use.
More recently, there has been interest in improving mud granaries to make
them more airtight and waterproof. This is especially important in areas
where insecticides are hard to get and where there is a lot of rain.
The Pusa Bin, which is discussed here, was
developed in India. It is made of mud
bricks. The walls are made by sealing
a layer of plastic sheet between two
layers of mud bricks. The mud bricks
protect the plastic from holes. The
plastic keeps air and moisture out.
<FIGURE 43>
51cp57a.gif (437x437)
Advantages:
* It is an airtight storage
structure.
* The materials are often available
locally.
Disadvantages:
* Plastic sheets are sometimes hard to get or expensive.
* It must be protected from rain by a separate roof.
* Sealing the plastic sheets may be a problem for a farmer.
THE IMPROVED MUD BLOCK SILO
The other plan presented here is the improved mud
silo, and is based on a plan prepared in Ghana.
VITA artist George Clark provided the illustrations.
<FIGURE 44>
51cp57b.gif (437x437)
The silo is made of mud bricks. This silo was
improved by plastering and painting the walls.
Plaster is usually composed of cement, lime
and sand. Mud plasters also can be used. Both
mud and plaster may not stick to the brick walls
for long periods of time. Mud plaster sticks
better for a time, but heavy rains can wash it
away. Efforts have been made to mix the mud
with a stabilizer such as cement, or bitumen;
this seems to work. Also, to make the plaster stick better, small stones can
be added to the mud used to make the bin walls.
Local material also can be used to paint and coat the outer walls. Some
materials which can be tried on the walls are:
asphalt resins
organic oils ox-blood
paints
These coatings last only a year or so, but they are cheap, available, and
easy to put on. See Appendix D for information on how to find and use local
materials to waterproof soil construction. When looking for a coating for an
improved mud silo, the farmer should remember he is looking for a material
which:
* is water-repellant.
* sticks to the walls.
* lasts long enough so he does not have to re-apply often.
The improved mud silo presented here has the following advantages and
disadvantages:
Advantages
* The materials are cheap.
* Airtight storage can be achieved or nearly achieved.
If the farmer is not sure the silo is airtight, he can
add insecticide to the grain.
* The emptying chute allows small amounts of grain to
be taken out without unsealing the top of the bin.
* It can be made in a number of sizes.
Disadvantages
* It requires regular painting or whitewashing.
* It may not be water-tight to prevent grain rewetting.
Since these earthen structures seem to be more easily made by small
farmers than the metal bins, the construction plans are given in more
detail. The mud silo presentation includes a set of instructions for
use of the silo.
THE INDIAN PUSA BIN
<FIGURE 45>
51cp59.gif (437x437)
The Pusa Bin was developed in India by members of the Agricultural
Research Institute in New Delhi. It is relatively simple and inexpensive
to construct and maintain. This bin is double-walled all the way round
-- including the floor and roof - with a separating layer of plastic
sheet. The plastic protects against moisture and keeps air from entering
the stored grain.
Protect the bin from rain. If the bin is not erected under a shed and it
rains often, it will require too much repair and rebuilding, and the grain
may get wet and mold. However, complete shading from the sun is not
necessary because mud walls do not hold heat. This is one advantage of
a mudblock structure over a metal bin.
In India, rats cause great storage losses. For this reason, in this plan
the bottom 50cm of the outside wall and the first layer of the floor slab
are made of fired, or "burned," bricks. These bricks are harder than
un-fired bricks, like mudblocks, and rats and mice cannot gnaw through the
bin walls or burrow up underneath the floor to get to the grain. Another
way to keep out rats and mice is to use sheet metal over whatever kind of
non-hardened material you use, in the same places.
This plan uses an insulating layer of plastic sheet. The Pusa Bin is
airtight and waterproof only if the plastic sheet is made and used
correctly. The plastic sheet used should be at least 700-gauge thickness,
to resist tears and punctures.
If plastic sheet is not available or if it is too expensive, some other
form of waterproofing will be needed in warm rainy areas. Check out what
is available locally. Tarfelt -- heavy paper impregnated with tar --
can be used. Experiment with bricks containing cement. Try painting the
bin with asphalt, coal tar or any other local waterproofing substance.
Remember, the bottom of the bin must be waterproofed to stop migration
(seeping of moisture from the earth below.
This plan is for a 2 metric ton bin. You may vary the size of the bin
to fit your needs. Make sure you build a strong enough roof support
frame for larger bins.
READ THE INSTRUCTIONS THROUGH BEFORE YOU BEGIN
Tools and Materials
* mudblocks and mud mortar for the walls. If you make blocks
10 x 10 x 20cm you will need about 900-1000 of them.
* wood to make a form for making mudblocks
* fired, or "burned," bricks, concrete blocks or bricks of some
other hard, rat-proof material for the floor and lower 50cm
of the walls. You will need about 250 of them.
OR
some sheet metal to cover mudblocks for the same purpose. You
will need 6-6.5 square meters, allowing for overlapping of
sections. If you use sheet metal instead of hard bricks, add
250 mudblocks to the number given above.
* cement mortar if you use fired bricks
* about 9 square meters of 700-gauge plastic sheet for moisture-proofing
the bin. Or the same area of tar-paper, or a suitable
amount of waterproofing material to give a good, thick coating
or several coatings.
* a piece of iron bar to heat and seal seams in the plastic
* wood or another strong material for making a roof support
frame
* sheet metal or plastic pipe for an emptying spout. Coated
wood will also work.
* some wax or similar material to seal some joints
* mud for making roof slabs
1. Select a site.
* Choose a place that is as high and dry as possible. It is
better to build up the earth a little for extra protection
against collecting rainwater. Level and firmly tamp down
the earth.
* Make the foundation area at least 1.5 x 2m.
2. Make mudblocks.
* Use the hard earth beneath the topsoil to make mudblocks.
If the soil in your area does not have a high clay content,
you may be able to mix a little cement in with low-clay soil
to make good mudblocks.
* A wood form can make several mudblocks at a time.
* If you use blocks measuring 10 x 10 x 20cm you will need about
900-1000 mudblocks. If you are going to use sheet metal instead
of fired bricks to protect against rats and mice, add 250 more.
3. Make the floor of the bin.
* Lay down a platform of fired bricks or other hardened bricks,
and cement mortar, measuring about 120 x 160cm.
OR
Lay down a layer of sheet metal and place a layer of mudblocks
and mud mortar on top of it, to the same measurements. Use
flattened kerosene tins or any available sheet metal. Overlap
all the pieces. Make the outside edges stick out about 15cm
beyond the outside edges of the block platform that will be
laid on top of it.
* Allow about 1cm thickness of mortar between either kind of
brick, for a good bond.
* Place a layer of plastic over the bricks, or whatever waterproofing
material you are using. It should extend a few
centimeters beyond each edge of the layer of bricks.
* Lay down a layer of mudblocks and mortar on top of the plastic,
the same size as the first brick layer.
<FIGURE 46>
51cp62.gif (486x486)
4. Build the inner walls.
* The inner walls may be made entirely of mudblocks and mortar.
* Make the outside edges of the walls the same as the outside
edges of the floor.
* Build an emptying spout into the first layer. Form something
like galvanized tin into a tube about 9 or 10cm in diameter,
or use a plastic pipe the same size. Fit one end flush against
the inside of the wall. Make it long enough to extend past
where the outside edge of the outer wall will be. You may
tilt it downwards slightly towards the outside for easier exit.
Mortar it into the wall. You will need a tight-fitting cap
on the end of the spout.
* Lay the blocks so that each one crosses over a joint between
blocks in the layer below it. This will make the walls stronger.
* Build the walls to a total height of about 160cm -- but wait
until installing the roof support frame (next step) before
putting in the final layer.
<FIGURE 47>
51cp63a.gif (486x486)
5. Install a roof support frame.
* Use wood that is naturally termite proof, or coat it with
something to protect it against these and other insects.
Metal or reinforced concrete bars can be used, but they will
be more expensive. The roof must have strong support: use
the best available material.
* Use four pieces as long as the distance between the outside
edges of the inner wall -- two pieces about 120cm and two about
160cm. Wood should have at least a 5 x 5cm cross section.
* Form the frame in a double-cross
pattern. Interlock wood joints.
One of the corner spaces should
measure about 50 x 50cm, for a
manhole entrance.
<FIGURE 48>
51cp63b.gif (486x486)
* Position the frame on top of the
next-to-last layer of blocks in
inner wall. Raise the ends up
on some mortar so the top surface
of the frame will be at the same
height as the top surfaces of the
final layer of mudblocks.
<FIGURE 49>
51cp64.gif (486x486)
* Mortar the frame and the blocks for the top layer of the wall
into place. Make a smooth top surface on the walls.
6. Build the inner roof.
* Make mud slabs 5cm thick for the inner roof.
* You may make one or more to cover each space in the support
frame, depending on how strong the slabs are. They will have
to support another layer of mud slabs the same thickness when
the bin is complete. It would be best to extend them to the
outside edges of the inner wall for firm support. Sections of
tightly stretched wire mesh fastened to the support frame
would provide extra support for the slabs.
* Position the slabs on mortar applied to the support frame and
the tops of the walls. Leave the 50 x 50cm manhole open.
* Fill any spaces between the slabs with mortar.
7. Plaster the inside.
* Plaster the insides of the walls and the roof, and the surface
of the floor with a smooth coating of mud or mortar. This will
leave no place for insects or dirt to lodge.
8. Make and install a plastic cover.
* Measure the outside dimensions of each of the four walls and
the roof.
* Cut pieces of plastic sheet to cover each of the five surfaces.
Each piece should be cut a little larger than the surface
which it will cover -- at least 5cm overhang on each edge.
The bottom edges of the sides must reach a few centimeters
beyond the plastic sticking out from the floor.
* Fasten the pieces together in a box shape. Keep in mind the
right arrangement of pieces so that when the cover is placed
over the bin it will fit.
* Seal the edges of the plastic together with a heated piece of
iron bar. Lay one edge over another and pass the iron over
them. Make sure the iron is not too hot: it should not melt
the plastic, but just seal it together. Make sure you have a
good seal. Practice making seams on small scraps of plastic
first. Find the right temperature for the iron.
<FIGURE 50>
51cp65.gif (486x486)
* Make sure there are no rough edges of blocks or mortar on the
walls or roof that will damage the plastic.
* Pull the cover all the way down over the inner structure of the
bin. If it is too small you will have to re-make it; you may
be able to re-work the seams. It does not matter if the cover
is too large.
* Cut a hole in the plastic around the emptying spout. Seal it
to the spout with something like soft wax. This should make
an air- and water-tight seal.
* Seal the bottom edges of the wall pieces to the edges of the
plastic in the floor.
* Cut a diagonal slit through the plastic across the manhole.
9. Build the outer walls.
<FIGURE 51>
51cp66.gif (486x486)
* Begin the walls from the earth foundation. Build them right
up against the plastic over the inner walls.
* Use fired bricks or other hardened bricks and cement mortar for
the lower 50cm of the outer walls
OR
Use mudblocks and mud mortar instead, building them up on the
metal sticking out from under the floor. Cover them to a height
of 50cm with overlapping pieces of sheet metal. Mortar or
otherwise securely fasten the metal in place. Make a good joint
with the metal sticking out from under the floor.
* Continue the outer walls with mudblocks and mud mortar.
Build them up to the top surface of the inner roof. If
there is any difference in height, fill with mortar.
10. Build the outer roof.
* Place 5cm-thick mud slabs over the plastic sheet on top of
the inner roof, mortaring them in place, out to the outside
edges of the outer walls. They may be any size across, as
long as they are strong.
* Do not cover the manhole. Make a separate mud slab to fit
over it.
* Fill in spaces between the slabs with mortar.
11. Finish the bin.
* Plaster the outer roof and sides with a smooth layer of mud
or mortar.
* Let the entire structure dry thoroughly. This will take about
thirty days. Leave the manhole cover off during the drying.
* A coat of whitewash put on after drying would help reflect the
sun's heat and add further waterproofing.
* Build a shelter over the Pusa Bin to protect if from the rains.
Make it at least a half meter larger than the bin on all sides,
and high enough to give plenty of room to load grain and get
in and out the manhole. There is no need to enclose the sides
of the shelter.
12. Prepare and use the bin for storage.
* When the bin is dry, clean the inside thoroughly. Light a small,
smoky fire to drive off insects. Take both of these steps each
time you get ready to load an empty bin.
* Dusting the inside surfaces of the bin with insecticide, and also
the grain, will protect the grain better.
* Cover the manhole when you have put your grain into the bin.
Seal it with extra mud or mortar for more protection.
* Always close the cover of the emptying spout tightly after using.
* Check the grain periodically.
* Store only grain which is dried to 12-13% moisture content in
the Pusa Bin.
IMPROVED MUDBLOCK SILO
READ THE INSTRUCTIONS THROUGH BEFORE YOU BEGIN
Tools and Materials
* Rocks about 20-25cm across for the foundation of the silo.
* Flat rocks, as wide across as possible, to lay across the
foundation.
* Sand for concrete and mortar.
* Small stones to mix in with the concrete.
* 2 bags of cement.
* Trowel or a similar tool to work the mortar and plaster
mixes.
* Different sizes of wood boards. The sizes are shown in
each part of the instructions where you will use them.
* Earth to make mudblocks.
* Nails (1.8-2.4cm long).
* Pitch, tar, or other waterproofing
material.
Select a Site
* Find some solid ground on which
to build the silo.
* High ground is best.
* Make sure the silo is built in
a place where the ground underneath
it will not wash away
during a rainy season.
<FIGURE 52>
51cp69.gif (486x486)
1. Make a Form to Mold Mudblocks
* Use wood boards about 2.5cm thick.
* You will need: 2 boards 46cm x 10cm
4 boards 10cm x 15cm
* Line the 2 long boards up side by side.
* Nail the 4 small boards crossways between them. Place the
small boards so that the distance between the 2 long boards
is 15cm. Leave 10cm space between each of the small boards.
Place the first small board about 2.5cm in from the ends
of the long boards. This should leave about the same amount
of space on the other end.
* Make handles. Use 2 small pieces of wood 2.5cm thick that
are 15cm long and about 5cm wide. Nail one across each
end of the box.
2. Make Mudblocks
* Mix earth and water to make the same kind of mud you use to
build any building.
* Wet the form.
* Fill the form with mud.
* Pack the mud tightly into
the form.
* Take any extra mud off the
top.
* Lift the form carefully off
the mudblocks.
* Dry the blocks in the sun.
* Make about 300 blocks.
<FIGURE 53>
51cp70.gif (587x587)
3. Make Frame "A" for the Outside of the Topslab
* To make this topslab you must make 4 wood
frames. Later you will pour concrete into
these frames.
<FIGURE 54>
51cp71a.gif (437x437)
* Prepare: 2 boards, 2.5cm x 5cm x 1.2m
2 boards, 2.5cm x 5cm x 1.1m
4 boards, 2.5cm x 5cm x 51cm
* Nail the 4 longer boards together. Butt
the ends of the 1.1m boards up against the ends of the 1.2m
boards. When the frame is lying on the ground,the 2.5cm edges
of the boards should be facing up.
* Nail these cross pieces in place from the inside. The 2.5cm
edges of these boards should also be facing up when the frame
is lying on the ground.
* Cut the ends of the 4 short boards at a 45 degree angle.
Then they will fit easily across the corners of the large
square frame.
<FIGURE 55>
51cp71b.gif (600x600)
4. Make Frame "B" for the Manhole
* Prepare: 2 boards, 2.5 x 8cm x 45cm
2 boards, 2.5 x 8cm x 40cm
* Cut part of the face off each end of the 4 boards.
This will make a slanted face.
* Nail the 4 boards together. Face the slanted sides outward.
Butt the ends of the 40cm boards up against the
ends of the 45cm boards.
<FIGURE 56>
51cp72.gif (486x486)
5. Make Frame "C" for the Collar
* Prepare: 2 boards 2.5cm x 2.5cm x 53cm
1 board, 2.5cm x 2.5cm x 56cm
1 board, 2.5cm x 2.5cm x 66 cm
* Nail the 4 boards together. Butt the ends of the 56cm board
up against an end of each of the 53cm boards. Butt the other
ends of the 56cm boards up against the 66cm board. Leave 5cm
of the 66cm board sticking out on one end.
<FIGURE 57>
51cp73a.gif (486x486)
6. Make Frame "D" for the Manhole Cover
* You will need: 2 boards, 2.5cm x 5cm x 61cm
2 boards, 2.5 x 5cm x 56cm
* Nail the 4 boards together. Butt the ends of the 2 shorter
boards up against the ends of the 2 longer boards.
<FIGURE 58>
51cp73b.gif (486x486)
7. Mix the Concrete and Pour it into the Wood Frames
* Mix the concrete in a proportion of: 1 part cement (out of the bag)
2 parts sand
3 parts small stones
Remember to mix the dry ingredients first. Then add the water,
a small amount at a time until the mixture is correct.
* Cover a flat place on the ground with empty cement bags or
sheets of heavy paper or plastic. These will keep the concrete
from sticking to the ground.
* Wet the empty bags or whatever you are using. This will keep
the concrete from sticking to them.
* Put Frame A on top of these.
* Place Frame B in the middle of Frame A. Make sure each side of
Frame B is the same distance from each side of Frame A. The
thin edges of Frame B should be facing down.
* Begin pouring concrete mix into the space between Frame A and
Frame B. The open space inside of Frame B will be the manhole.
* When you have poured in about half the thickness all the way
around, lay in the metal rods.
* Pour the rest of the concrete mix over the rods.
* Make sure the rods are in the concrete. They should not show
through the concrete. If you do this right, the rods will help
make the concrete much stronger.
<FIGURE 59>
51cp74.gif (486x486)
* Level the concrete even with the top of Frame A. Frame B will
stick up 2.5cm above the wet concrete.
* Place Frame C around Frame B on top of the wet concrete. The
space between the two frames must be the same on every side.
* Pour concrete mix into the space between Frame B and Frame C.
Make the top of the concrete level with the tops of the 2 frames.
This will form a collar for the manhole cover to rest on.
* You are now ready to use Frame D to make a separate piece. This
will be the manhole cover.
* Place Frame D on some empty cement bags or sheets of heavy paper
or plastic.
* Wet the empty bags or whatever you are using.
* Pour concrete mix into Frame D. Level off the top of the concrete
to the top of the frame.
* Leave all the frames around the concrete for at least 3 days.
The concrete will become even stronger if you can leave it for
several more days.
* While the concrete is drying, put water on it 3 times each day
at morning, noon, and night. Putting water on the concrete like
this will make it harden evenly and not crack. This is called
"curing."
* When the concrete is Cured," remove the wood frames. Remove
them carefully, so you can use them again.
<FIGURE 60>
51cp75.gif (486x486)
8. Make the foundation
* Draw a circle on the ground where you want to build the silo.
Make the circle 1.2m across.
* Place the 20cm or 25cm rocks around the circle just inside the
edge, and inside the circle. You may fill in the larger spaces
with smaller rocks to give more support. The air spaces between
the rocks will let air move through the foundation and will
keep moisture from collecting.
* Place flat rocks on top of the circle of rocks. This will make
the top more level.
* If you cannot find good flat rocks, you may use concrete blocks.
Place them the same way as you would the flat rocks. Place
them so they come right up to the edge of the circle of rocks,
or overhang slightly.
* Make some mortar by mixing 1 part cement and 5 parts sand together.
Add enough water to make a workable paste.
* Put mortar over the flat rocks or blocks. Fill all open spaces.
Make the surface as smooth as you can. This will cement the
top of the foundation into a solid piece.
* Find the center of the foundation.
* Mark off a 91cm diameter circle from the center. This is the
inside diameter of the silo.
9. Build the Grain Chute (Optional)
* Use hard wood about 2.5cm thick.
* Prepare: 1 board, 2.5 x 15 x 30cm -- for the top of the chute.
1 board, 2.5 x 15)(25cm - for the bottom of the chute.
2 boards, 2.5 x 10cm that are 25cm long on one edge and
30cm long on the opposite edge. These are
for the sides of the chute.
1 board, 2.5cm thick, at least 13cm wide,and 20cm or
25cm long. This is for the sliding door
in the chute.
* Place the edge of the sliding door board on one of the side boards
5cm in from the short straight end. Trace the width of this edge
onto the side board. Make a groove. Remove the wood between the
2 lines you have traced to a depth of about 6mm. Make each
surface of the groove as smooth and as straight as you can.
* Repeat this process on the other side board. The groove should
be in the same place on each side board.
<FIGURE 61>
51cp77.gif (600x600)
* Cut the top board into two pieces. One piece should be 5cm
long. This will fit the space between the front of the chute
and the beginning of the groove for the sliding door. Match the
edge of the remaining piece with the far end of the groove. Cut
the length of the top piece as needed to match the length of the
side piece.
* Nail the top and sides and bottom of the chute together.
* Trim the width of the sliding door board so that it will slide
through the opening in the top of the chute down the grooves.
* You may have to trim the long sides of the opening too if the
sliding door is too thick. The sliding door should move freely
up and down but should not be too loose.
* Cut the bottom edge of the sliding door at an angle so that only
a thin edge will touch the bottom of the chute. This edge will
face the outside of the silo. This will make it easier to keep
grains from lodging under the closed door which might let air
and moisture and insects into the silo.
* Paint the chute and the sliding door with pitch or tar or some
like material to protect it from insects and moisture.
* Drive a few nails into the chute near its slanted end. They
should stick out a couple of centimeters. The nails will
help anchor the chute into the walls of the silo.
10. Begin the Walls
* Make mortar the same way you did for the top of the foundation.
It is better to mix smaller amounts until you know how fast you
can use it. Do not use mortar that has gotten too dry because
it will not be as strong.
* Lay down a layer of mortar all around the inside edge of the
circle you have drawn on the top of the foundation. Make it
about 10cm wide.
* Place about 18 mudblocks in a circle on top of the mortar. Leave
a space for the chute, including the nails that are sticking out
from it.
* Place the chute in the space you have left. The slanted end of
the chute should be even with the inside surfaces of the blocks
next to it and straight up and down. This will make the
chute tilt down away from the silo wall.
<FIGURE 62>
51cp78.gif (486x486)
* Fill the spaces between the mudblocks and the spaces between the
mudblocks and the chute with mortar.
* Lay down a layer of mortar on top of the circle of mudblocks.
* Place the second layer of mudblocks on top of the first. Place
each block so that it lays across the space between the blocks
in the first layer. This will make the wall stronger. You
may have to cut blocks to fit next to the chute. Do not leave
a large space that will have to be filled with mortar next to
the chute.
* Continue putting on mortar and mudblocks in the same way until
you have laid down 4 layers of mudblocks altogether.
11. Make a Slanted Floor
* Use sand or soil to make a slanted floor. This will help the
grain move towards and out of the chute. If the chute is not
used, this slant will not be needed.