Compost pits are used
to prepare organic manure which have long livespan and do not alter the soil
Ph. These organic fertilizers
provide the food needed for a plant to grow after a seed has germinated in the soil. This food
consists of plant nutrients which are nitrogen
(N), phosphorus (P) and potassium
(K). There are also many other chemicals needed by plants
in small quantities, e.g. copper (Cu), manganese
(Mn), magnesium (Mg), iron (Fe), sulphur (S) and others. These are called micronutrients or trace
elements. Natural fertilizer also provides organic matter called humus for the soil. Humus is a black or brown spongy or jelly-like
substance.
It helps the soil have a good structure to hold water and air. One of the best natural fertilizers is mature compost
because it feeds
the soil with humus and plant nutrients. The growing
plants take their nutrients from the top layer of the soil where their roots grow.
Plant nutrients are lost from the soil when they are washed down (leached) below the top soil, or when the top soil is eroded.
Plant nutrients are also lost with the crops
when these are harvested. When the surface
of the land is broken
up for farming,
the soil is often eroded: it is blown away by the wind or washed away by rain and floods.
The soil also loses much of its carbon content
as carbon dioxide (CO2)
into the atmosphere, thus contributing to climate change.
The soil that
is left becomes
poor in plant nutrients so the crops do not grow well and give a good yield. But if the plant nutrients and carbon are returned to the soil,
it can continue to grow good crops as well as contribute to slowing
down the negative impacts of
climate change.
Importance of Compost manure
Compost is important because it:
1. Contains the main
plant nutrients – nitrogen (N),
phosphorus (P) and
potassium (K), often written as NPK;
2.
Improves
the organic matter in the soil by providing
humus
3.
Helps
the soil hold both water and air for plants;
and
4.
Makes trace
elements or micronutrients available to plants.
Uses of compost manure
Compost is made up of humus, it can be used for improving soil as follows
1.
It provides plant nutrients
that are released throughout the growing season,
the plant nutrients are released when organic matter decomposes and is changed into humus, this plant
nutrients dissolve in the water in the soil and are taken in by the roots of the crops.
2.
It improves soil structure so that plant roots can easily reach down into the soil, in sandy soil
the humus makes
the sand particles stick together. This
reduces the size of the spaces (pores)
so that water stays longer in the soil.
In clay soils, the humus surrounds the clay particles making more spaces (pores) in the soil so the root systems of plants can reach the water and nutrients that they need, and air can also move through the soil, therefore, because heavy clay soils become lighter and sandy soils become heavier, soil that has had compost added
to it is easier to work, i.e. to plough and dig.
3.
It improves the moisture-holding
capacity of soil. The humus is a dark brown or black soft spongy or jelly-like substance that holds water and plant nutrients. One kilogram of humus can hold up to six litres of water. In dry times,
soil with good humus in it can hold water
longer than soil with little humus. When it rains, water easily gets into the soil instead of running off over the surface. Water gets into the subsoil
and down to the water table, runoff and thus flooding is reduced, and springs do not dry up in the dry season.
4.
It helps to control weeds,
pests and diseases. When weeds are used to make compost,
the high temperature of the compost-making process kills many, but
not all, of the weed
seeds. Even the noxious weed, Parthenium, has most of its seeds
killed when it is made into compost Fertile soil produces strong plants able to resist pests and diseases. When
crop residues are used to make compost, many pests and diseases cannot
survive to infect the next season’s crops.
5.
It helps the soil resist
erosion by wind and water. This is because: Water can enter the soil better and this can stop showers building
up into a flood. This also reduces
splash and sheet erosion.
Soil held together with humus
cannot be blown
away so easily
by wind.
6.
Compost helps
farmers improve the
productivity of their
land and their
income. It is made without having to pay cash or borrow money, i.e. farmers do not have to take credit and get into debt like they do for taking chemical fertilizer. But, to make and use compost properly
farmers, either individually or working in groups, have to work hard.
Components of making Compost
1. Plant materials, both
dry and green
a)
Weeds, grasses and any other dry plant
materials cut from inside and around fields, in clearing paths, in weeding, etc
b)
Waste from cleaning grains, cooking and
cleaning houses and compound, making food and different drinks, particularly
coffee and tea
c)
Crop residues; stems, leaves, straws and
chaff of all field crops, both big and small cereals, pulses, oil crops,
horticultural crops and spices, from threshing grounds and from fields after
harvesting
d)
Garden wastes; old leaves, dead flowers,
hedge trimmings and grass cuttings
e)
Dry grass, hay and straw left over from
feeding and bedding animals. Animal beddings are very useful because it has
been mixed with the urine and the droppings of the animals
f)
Dropped leaves and stems from almost any
tree and bush except plants which have tough leaves or leaves and stems with
strong smells or liquids when crushed, like Eucalypyus, Australian Acacia,
Euphorbia etc
g)
Stems of Cactus, such as prickly pear,
can be used if they are crushed or chopped up, they are good source of moisture
for making compost in dry areas
2. Water
Enough water is needed
to wet all the materials and keep them moist, but the materials should not be
made too wet so that they lack air and thus rot and smell bad. Both too little
and too much water prevents good compost being made
Water does not need to
be clean and can be collected from
a)
Collected rain water
b)
Collected waste water e.g. from washing
pots and pans, clothes, floors
c)
Human and animal urine
d)
Ponds, dams, streams and rivers
3. Animal Materials
a)
Dung and droppings from all types of
domestic animals including horses, cattle, goats, from night pets and even
collected from fields
b)
Chicken droppings are important to
include in compost because they are rick in nitrogen
Compost making aids
1.
Micro-Organisms (Bacteria and fungi) and
smaller animals like earthworms, nematodes, bettles and insects turn waste
materials in to compost manure
2.
Air – Air circulation in a compost pit
is necessary because soil organisms responsible for the manure formation
require oxygen for their survival
3.
Heat- Decomposition of organic wastes
produces heat. Compost needs to be kept hot and moist so that the plant and
animal materials can be broken down quickly and thoroughly. Heat destroys most
of the weeds, fungal diseases, pests and parasites
