How To Enrich The Soil….
Causes Of Loss Of Soil Fertility
Soil is said to be fertile when all the nutrients necessary for plant growth and development are present in it. Soil can lose its fertility in five main ways: burning, leaching, erosin, crop removal and clean clearing.
Burning
In some places, big forests and vast grasslands are set on fire to burn. Some of these areas are good farmlands. When this is done, dead and decaying leaves, grasses and living soil organisms are burnt. Dead leaves, grasses and soil organisms add fertility to soil. Soil therefore, loses its fertility whn they are burnt.
Leaching
This is the downward movement of nutrients from the top soil to the underground layers of the soil. Some nutrients dissolve in water for plants to absorb as food.
When rain falls, some water collects in low-lying areas of the farm and stays there for some time. As this water sinks into the soil, it carries with it dissolved soil nutrients. These nutrients can no longer be available to the plants growing on the surface of the soil. The nutrients are lost. The nutrients are lost or leached away.
Erosion
This is the gradual wearing away of the top soil by water or wind. When rain falls, water flows on the surface of the soil. The water carries the top soil along with it. The top soil contains nutrients dissolved in water. These nutrients are carried away by the flowing water and are no longer available for plants to use.
Wind blowsand carries some soil particles from one place to another. This soil contains some nutrients which are also carried away by the wind.
Crop Removal
The crops that farmers plant in their farms absorb nutrients from the soil for their growth and development. These nutrients, once taken up or absorbed, are no longer in the soil. Another crop planted in the same soil the following year may not have sufficient nutrients for its own growth and development.
Clean Clearing
Leaves on forest trees drop on the soil. These leaves die and decay, and add nutrients to the soil. When these trees are removed and the forest undergrowths cut, the soil loses its regular supply of nutrients from the forest.
Ways Of Making Soil Fertile
We can make soil fertile in the following ways:
i. Planting Cover Crops:
Cover crops are mainly legumes, such as cowpea and mucuna. These crops add humus and mineral salts to the soil through their leaves and roots.
ii. Adding Green Manure:
This involves ‘burying’ young green plants in the soil. When these decay, they add organic matter to the soil. Examples of green manure are soya beans, centrosema and calopoginium.
iii. Adding Compost Manure:
Compost is decayed plant and animal material. When compost is added to the soil, it supplies humus and mineral salts to the soil for plant use.
Materials For Making Compost Are:
1. Soft remains of vegetable and farm crops.
2. Weeds and grasses from the farm.
3. Compound And Kitchen Refuse.
4. Animal Dung.
5. Wood Ash.
6. Water.
7. Urine.
Iv. Adding Farmyard Manure (FYM):
Farmyard manure is made up of all the beddings, faeces or droppings and urine of farm animals. It is added to the soil to make it rich in plant food.
V. Adding Fertilizers:
Fertilisers are chemical substances which are added to the soil to increase plant food. They are usually available in bags. Examples of fertilizers are NPK, sulphate of ammonia and urea.
Vi. Mulching:
This is the practice of covering the top of seed beds with dry plant leaves and grasses. The dry leaves decay and add organic matter to the soil. Mulching also prevents the sun from heating off and evaporating some of the available nutrients in the soil.
Ways Of Maintaining Soil Fertility
There are many ways of maintaining soil fertility: crop rotation, fallowing, shifting cultivation, weeding, terracing, ridging and making crossbars or ridges.
Crop Rotation
This is a farming method whereby crops are rotated or made to grow on the plots every year in a planned manner. Crop rotation is, therefore, a useful method of maintaining soil fertility.
Fallowing
In crop rotation, there is usually a plot that is left to fallow or rest every year with a crop like mucuna growing on it. This practice helps to maintain soil fertility.
Shifting Cultivation
A farmer may plant crops on a piece of land in a year. The next year, the farmer leaves that plot and moves to another piece of land because plant food has been taken up by the crops in the first plot. This is called shifting cultivation, and it is done to enable the old plot of land to regain the lost plant food.
Weeding
Weeds are unwanted plants growing in the farm. Weeds compete with the planted and wanted crops for food. When these weeds are removed, nutrients are retained in the soil for plant use. Weeding is the name given to removal of weeds.
Terracing
A slopy land can be terraced to prevent soil nutrients from being washed away by rain or running water.
Ridging
Farmers make ridges across the slopes to prevent excess running water from carrying away soil nutrients.
Making Crossbars Or Cross Ridges
Crossbars are made between ridges to prevent soil nutrients from being carried away by water flowing along the farrows.
SUMMARY
In this article: you have learnt that:
1, Soil fertility can be lost by burning, leaching, erosion, crop removal and clean clearing.
2. We can make soil fertile by planting cover crops, adding green manure, adding farm-yard manure, adding fertilisers and mulching.
3. Farming practices, such as crop rotation, fallowing, shifting, cultivation, weeding, terracing, ridging and making crossbars or ridges, can help to maintain soil fertility.
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