Transition from conventional to alternative agriculture in Pakistan: the role of green manures in substituting for inorganic N fertilizers in a rice-wheat farming system
1995
Hussain, T. | Jilani, G. | Parr, J.F. | Ahmad, R.
Nitrogen, a vitally important plant nutrient, is subject to various losses that affects its efficiency. We tested prilled urea (PU), urea supergranules (USG), green manures (CM) and farmyard manure (FYM) in a rice-wheat cropping system to determine which were the most efficient and economical N sources. The maximum rice growth, yield and N-uptake occurred with USG and with GM (Sesbania rostrata) plus PU. Incorporation of GM saved 60 kp N/ha. On the following wheat crop, GM (S. aculeata) plus PU and FYM plus PU had the highest residual effect on the number of tillers per m2, and straw and grain yield. An increase in N recovery efficiency occurred with combined use of PU and organic/green manures compared with PU along. In areas were USG is costly or unavailable and FYM is scarce, green manures can be a cheap N source that allows small-scale farmers to get sustainable yields in a rice-wheat rotation.
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