Write short notes on the following: (a) bush burning; (b) clean clearing; (c) organic manuring

(a) Bush burning

Bush burning is the setting of fire to natural vegetation or crop residues on a piece of land, usually to clear it for farming or hunting. It is a cheap and quick way of clearing land and destroys some weeds and pests. However, it has serious harmful effects: it destroys soil organisms and organic matter, reduces soil fertility, exposes the soil to erosion, destroys wildlife and its habitat, and pollutes the air. Because of these effects, bush burning is generally discouraged in good farming.

(b) Clean clearing

Clean clearing is the complete removal of all vegetation, stumps and roots from a piece of land, leaving the soil surface bare before cultivation. It gives a clean seed bed and makes mechanised operations easier. Its disadvantage is that it leaves the soil exposed to the direct impact of rain and sun, leading to loss of organic matter, leaching and severe soil erosion. It is best combined with cover cropping or mulching to protect the soil.

(c) Organic manuring

Organic manuring is the application of manures obtained from plant and animal remains (such as farmyard manure, compost, green manure and poultry droppings) to the soil to improve its fertility. It supplies plant nutrients slowly, adds humus, improves soil structure, water-holding capacity and aeration, and encourages the activity of beneficial soil organisms. It is cheaper than inorganic fertiliser and has a long-lasting effect, though it is needed in large quantities and its nutrient content is low and not precisely known.