Priya HR, Veena, Pavithra AH and Divya Joythi.
Weeds not only adversely affect the plant productivity but many of them also cause health hazards in human-beings and animals. They also affect seriously the biodiversity. Apart from this, they may have numeral beneficial properties in one way or the other and have immense potential as food and fodder, medicinal, aromatic, phyto-remediation, industrial, soil and water conservation resources etc. Organic farming is defined as production system which avoids or largely excludes the use of synthetically compounded fertilizers, pesticides, growth regulators and livestock feed additives to the maximum extent feasible. The main aims of organic farming are to achieve food and nutritional security, to encourage long term maintenance of soil fertility, crop productivity and soil health, to encourage and enhance biological cycles within the farming system, involving microorganisms, soil flora, soil fauna, plants and animals. This also help in conserving, developing and utilizing the natural resources in the efficient way, to recycle/reuse biomass materials either on farm or elsewhere in order to minimize pollution that may result from agricultural practices. Biodegradable material of microbial, plant or animal origin shall form the basis of the fertilization programme in organic farming. Generally in India, FYM and compost are the main sources of manuring. However these have become scarce and costly due to reduction in the cattle population and increase in mechanization. Besides, applications of leaf manuring and crop residue incorporation are also in practice to some extent. There are some weeds species which are largely available can also be used as organic manures.