We will discuss here about the fertility of soil. We know that soil and water are needed to grow plants. But for their proper growth some other factors or elements are also necessary. They are obtained by the soil from manures and fertilisers.
Farmers often use compost manure and urea-fertiliser. The excreta of some animals like goat, sheep, cow, hen, etc. is also used to raise the fertility of the soil. Plants need nitrogen, phosphorus, iron, zinc, etc. for their growth which they receive from the soil. If there is a shortage of any one of these elements in the soil then, that should be fulfilled by applying appropriate manure or fertiliser. Thus plants grow in the soils with and without manure.
Farmers should know about deficiencies of the soil in their fields. There are laboratories for soil testing and farmers may utilise these laboratories. The deficiency can be overcome by adding suitable fertilisers.
There are some animals and insects that help the farmers in fertilising their fields. They dig the soil and facitilate air and water to enter it. Rabbits and rats dig the soil for their dwellings. Earthworms, scorpions, ants, etc. break up the hard portions of the soil and make it soft. The earthworm is known as the most faithful friend of the farmers.
Farmers plough their fields. The ploughing makes the soil fertile. It makes the soil turn over. It also helps in making the soil, fine and powdery.
Some green plants growing in the fields, serve the purpose of green manure. They are decayed in the soil and become useful manure. Hump is one of the green (plant) manures.