Crop Residue

Crop Residue remnant or stubble from all types of crops. These are a valuable part of the total soil organic matter. Roots, stubble, leaves and whole stalks add considerably to the total amount of organic matter. bacteria, earthworms and other desirable life in the soil increase when crop residues turn into soil. Three seasonal paddy groups are recognised in Bangladesh: aus, sown in the pre-monsoon season and harvested in the monsoon season; aman, grown in the monsoon season and harvested after the monsoon; and boro, grown in the dry season. wheat, corn and pulses also produce straw but the total production of such crops is not known in our country. A surface mulch of straw reduces soil detachment by water or wind, improves soil structure, increases the infiltration of water, reduces wind erosion, equalises soil temperature, smothers weeds, reduces evaporation, encourages earthworms and increases plant growth.

Of the total crop residues produced in Bangladesh, paddy residues comprise about 70%. Like other developing countries, the people of Bangladesh use crop residues as a building material and a fuel, and also to improve the soil. It should be recognised that crop residues provide substrates for beneficial microorganisms as well as deleterious ones. Bacteria and fungi, which utilise straw, can produce polysaccharide gum that aggregate soil particles and prevent erosion. Recently encouraging beneficial results have been obtained through the residual effect of a leguminous green manuring plant, Sesbania rostrata. Many researchers reported that rice straw at the rate of 10 in ton/ha might be applied for wheat production in bangladesh soil. Since straw has alternative uses such as cattle feed, litter and industrial processes. This increases the demand and thus the price and makes it less attractive for the farmers to incorporate and sometimes transport it back to the field. Although there is an increased yield reported in Bangladesh, this is not sufficient to induce farmers to use crop residues (straw) as a general practice. [Md Khalilur Rahman] [Rahman, Md Khalilur  Professor of Soil, Water and Environment, Dhaka University]