Robert H. Faust Ph.D.
The following information represents an attempt to distill
a great deal of information into a practical technique designed
for the small scale and limited resource farmer. The concepts
and methods can be scaled up with equipment to allow for production
of large quantities for the large or capital intensive farm. The
method described is a fast method of composting (60 days) as opposed
to more traditional methods taking up to 6 months and requiring
repeated turning and watering that results in large losses of
nitrogen. Nitrogen is a major yield limiting factor in many tropical
areas and effects protein levels in a positive way if nitrogen
levels are optimum. The following composting method saves nitrogen
and provides for a stable form of nitrogen which is released slowly
over the growing period and not leached away, before it is needed
to increase protein levels in the crop. The use of rock minerals
in the compost helps provide a balance so that major and minor
minerals are available for healthy plant growth.
Benefits of a "biomass fertilizer" over salt fertilizers
Applications of commercial fertilizer alone without consideration
of trace elements, organic matter, or biological activity results
in "decline" symptoms in the crop with resultant yield
reduction over time, eventually causing an economic decline on
a local and/or national level. The decline also puts a strain
on the health of the population and declining protein levels take
their toll in the next generation due to poor health. Lack of
sufficient quality and quantity of proteins for normal brain development
can result in a population less capable of coping with more and
more complex agricultural and social problems. This is the benefit
of the described methods of fertility management, as they provide
for mineral nutrition of the crops as well as providing for organic
matter and biological activity. The key to a living soil is constant
production of humic acids from organic matter. Once the organic
mater is gone problems develop which are difficult to cope with
even in the most advance agricultural systems let alone at the
small grower level. Problems with nutrient interactions due to
the lack of the buffering effects of humus/humic acid can cause
deficiency in crops and man, even if the total nutrient level
is sufficient. The use of the methods described in the handbook
allow for use of local wastes as well as encouraging the production
of nitrogen fixing trees to be used in bio-mineral fertilizer
production.
The production of organic acids by microbes aids the breakdown
of rock minerals which may be obtained locally. The use of rock
powders obtained from rock crushing operations or dug from natural
alluvial deposits. Many types of rocks have value when powdered
and subjected to bacterial action in a compost pile or mixed in
the surface mulch layer and allowed to decompose near the soil
surface.
Ligno-cellulosic wastes used
Ligno-cellulosic wastes include crop residues like straw, leaves,
twigs, husks, shells, bagasse (from sugar cane), corn stalks,
coffee pulp, etc. Other materials include weeds, grasses, and
biomass directly grown for composting. The weeds and grasses can
be mowed and harvested from waste areas on the farm or grown on
lands unsuitable for crops. Large quantities of lawn clippings,
brush and weeds are usually available from several sources including
the commercial tree trimmers (already chopped) and from landfill
sites. Even water weeds such as azolla, water hyacinth, blue green
algae and practically any other aquatic plant are usable, some
of which such as azolla are nitrogen fixers.
Manure not always needed
Research shows that manure can reduce decomposition in the compost.
The important thing to remember is that manure is not what makes
compost "breakdown"; what is important is a carbon/nitrogen
ratio of 30 to 1. If manure is used to obtain more nitrogen to
produce the right ratio, then it is helpful; otherwise it is not
necessarily needed as long as the inoculant slurry is used.
Carbon to nitrogen ratio crucial
This may be the most critical consideration when making a good
compost fertilizer. Carbon/nitrogen ratio means how much carbon
(organic matter) and how much nitrogen does it contain. The optimum
ratio is 30 to 1, or 30 pounds organic matter to 1 pound of nitrogen
for fast results and a high nitrogen product when you are done.
It may be necessary to send a sample to a local lab and find out
what your ratio is; if there is too much carbon and not enough
nitrogen more nitrogen can be added such as alfalfa or clover
or even fertilizer or natural urea can be added. If too much nitrogen
is present then some more high carbon raw materials need to be
added such as straw, grass, bagasse, paper, etc.
Molasses favors fungi over bacteria to speed up process
Fungi produce enzymes that can break down lignin and cellulose.
Bacteria then take over and finish the job forming humus. What
takes so long is that most composting is not done with fungus
initially. The key is to favor fungi right from the very start,
as fungi can break down ligno-cellulosic waste without high temperatures.
It has been demonstrated that the addition of molasses to the
pile will favor fungi over bacteria and can speed up the whole
process dramatically. 500 ml per 4 kg (2 pints per 10 pounds dry
waste) waste works good and probably adds trace minerals. Molasses
is cheap in many areas and may be available from feed stores or
sugar factories. Either cane or beet can be used.
Natural inoculation works best and is easy to prepare
Research has shown that an inoculant can speed up composting by adding benefical fungi and bacteria. These soil micro-organisms are beneficial to the soil the crop and to man. Soil microorgnisms break down the organic residues and applied compost or manure. Plants have no stomachs but require many minerals in a soluble form; the soil is the stomach of the plant and fungi and bacteria produce the chemicals that breakdown the organic matter. These good microbes need food to live and reproduce. The compost and organic matter applied to the soil provides their food. Bad microbes cause disease by feeding on a crop plant, they do not build organic matter. The good microbes which you add and help by adding compost also eat these bad disease causing microbes and help keep your crops healthy, making them essential to good crop production. You can make a microbial soil inoculant yourself on the farm with as good of results as the kind you buy. The inoculant can be mixed in a bucket and should contain 5% each of manure, good topsoil and compost made from crop residues. Add water to make up the balance (85%) then use 1 liter (1 qt) per square meter (yard) of raw materials sprayed or sprinkled on when the pit or pile is made up.
Moisture content important
Research has shown that 70% moisture is the best for composting
- most failures are caused by drying up of the pile after it starts
to heat. Water must be added by a sprinkler in absence of rain.
Initially enough water should be added so that when a handful
of media is squeezed a few drops of water drip out but the material
is not saturated. To get an accurate moisture content take a kilogram
of wet compost, dry it and compute the percent lost, which is
the water. After doing this you will learn what 70% moisture feels
like. It may be difficult to wet materials like dry straw, especially
when trying to water a pile. The best method is to spread out
the materials in a flat pile, add water with a sprinkler or allow
the rain to wet, then stack the material in a windrow up to 6
ft. high with sides as steep as possible. Turn the pile and water
when it reaches about 140 F (60 C) or when the heat in the pile
burns the hand when it is thrust into the pile.
Ground rock phosphate or coral lime is added
Rock phosphate or limestone/rock dust helps reduce nitrogen loss
to the air by stabilizing the compost. The optimum amount to add
has been shown to be about 1 to 4, or about 1 pound ground rock
phosphate to 4 pounds waste material on a dry weight basis.
Soil testing to fine tune formula
A soil test will let you know if your soil is low in essential
nutrients like phosphorus, calcium, potash, zinc and if it is
too acid or alkaline (the pH). If for instance, the soil is high
in phosphate but low in calcium and with an acidic pH then one
would want to add lime or crushed coral or rock dust instead of
rock phosphate. If on the other hand the soil is low in potash
(potassium), then wood ashes or potash fertilizer is added.
Pit Composting
Compost can be prepared in a pile or in a pit depending on conditions
present and personal preferences. Pits can be advantageous when
the climate is dry and maintaining 70% moisture is a problem.
Pit composting can be handy for planting in the finished pit.
A tree or tropical root crop like taro, sweet potato, yam or even
Irish potatoes can be planted in the pit by mixing soil with the
compost or if the compost is stable and stopped heating and animals
start appearing (worms, insects, centipedes, etc.).
Very high yields are possible with planting directly into one
of these pits. Several pits can be used when a continuous supply
of compost is needed. In general a 1 meter by 3 meter by 1 meter
deep pit should supply adequate compost for a 500 square meter
garden.
How to construct a compost pit
1. Dig a pit about 1 meter deep.
2. Place corn cobs or branches at the bottom of the pit to allow
for air circulation and drainage: do not mix with rest of pile.
3. Add materials such as leaves, manure, hay, straw, ashes, minerals,
to the optimum carbon/nitrogen ratio of 30 to 1. Add water to
make up 70% moisture and mix.
4. Leave the pit or pile for 60 days. Mix (and water if needed)
after 5, 15, and 30 days.
How to use the compost
The rate to use depends on the soil you are using it on: for most
gardens 2 sacks of compost (about 200 pounds or 100 kg) per 10
square meters, and for light or sandy soil, one sack may be plenty.
Do not turn compost under but spread it evenly on the surface
and work it into the upper layer of soil. Add compost at the beginning
of the dry season and at the beginning of the wet period for best
growth. The compost can be top dressed or lightly mulched around
a growing vegetable crop; for best results it should be covered
with a mulch like leaves, grass, or paper to keep it from drying
out or leaching away. The mulch over the compost helps earthworms
which will come to feed in the compost layer.
Storing compost
Heaping the compost into a steep sided pile or mound, not long
windrows is best. Covering the pile with organic residue or leaves
is a good idea to prevent drying during the dry season or leaching
in the wet season.
Materials needed
1. One burlap bag or grain sack (50 kg size)
2. Animal manure (fresh, wet) or compost
3. A few large rocks
4. A watertight pit or a 55 gal. drum
5. Water
How to make it
Fill the 50 kg bag 3/4 full of wet manure and tie the open end.
Place the bag into the pit or drum and fill with water at a ratio
of 2 liters of water to 1 kg wet manure. This will produce 100
liters of liquid fertilizer.
Additional materials such as boodmeal, kelp extract and urea can
be added if available.
Place the rock on the bag to hold it down in the water.
Remove the bag in about 3 weeks.
How to Use It
Apply around the base of plants 2-3 weeks after germination or
transplanting, repeat in a month. Use about 1/2 liter per meter
of row or 1/2 liter per plant on large plants, 1 liter on trees.
If plants start to yellow, try watering with it.
Gather raw materials
Try to gather materials to produce the right ratio of carbon to
nitrogen. If you have large amounts of low nitrogen straw or grass,
add some nitrogen fixing plants like clover, desmodium, leucaena,
etc. Banana trash adds potash but little nitrogen, so add chopped
leaves of a nitrogen fixing tree or manure or green weeds.
Make up pile with 30-1 carbon/nitrogen ratio
The optimum ratio is 30 to 1, or 30 pounds organic matter to 1
pound of nitrogen. It may be necessary to send a sample to a local
lab and find out what your ratio is; if there is too much carbon
and not enough nitrogen more nitrogen can be added such as alfalfa
or clover or even fertilizer or natural urea can be added. If
too much nitrogen is present then some more high carbon raw materials
need to be added such as straw, grass, bagasse, paper, etc.
Add minerals like rock dust, lime, rock phosphate
Rock phosphate or limestone/rock dust helps reduce nitrogen loss
by stabilizing the compost and preventing nitrogen loss to the
air. The optimum amount to add has been shown to be about 1 to
4, or about 1 pound ground rock phosphate to 4 pounds waste material
on a dry weight basis.
Apply slurry inoculant
The inoculant can be mixed in a bucket and should contain 5% each
of manure, good topsoil and compost made from crop residues. Add
water to make up the balance (85%) then use 1 liter (1 qt) per
square meter (yard) of raw materials sprayed or sprinkled on when
the pit or pile is made up.
Apply Molasses
500 ml per 4 kg (2 pints per 10 pounds dry waste) waste works
good and adds trace minerals. This can be mixed with warm water
and sprayed on while the pile is being made up or combined with
the inoculant and sprayed on or watered in.
Stack in long low piles
Pile the compost 6 to 10 feet high and 4 feet wide and cover with
leaves.
Keep moist
To really get an accurate moisture content take a kilogram of
wet compost, dry it and compute the percent lost which is the
water. After doing this you will learn what 70% moisture feels
like. It may be difficult to get materials like dry straw wet,
especially when trying to water a pile. The best method is to
spread out the materials in a flat pile, add water with a sprinkler
or allow the rain to wet, then stack the material in a windrow
up to 6 ft. high with sides as steep as possible.
Turn the pile and water when it reaches about 140 F (60 C) or
when the heat in the pile burns the hand when it is thrust into
the pile.
Alley Cultivation Grows Fertilizer In Your Field
Growing nitrogen fixing trees in rows between crop plants provides
many benefits, including protection against wind and shading young
tender plants. Nitrogen fixing trees provide a way of extracting
minerals from the soil with a deep taproot. Nitrogen is extracted
from the air with the aid of rhizobia, a type of beneficial bacteria
which forms nodules on the roots.
The prunings can be composted by the above method or chopped and
worked into the ground and allowed to break down prior to planting
your crop.