THE VALUE OF POULTRY MANURE FOR WETLAND RICE GROWN IN ROTATION WITH WHEAT

Poultry manure applied alone or in combination with urea at different N levels was evaluated as a N source for wetland rice grown in a Fateh pur loamy sand soil. Residual effects were studied on wheat which foll owed rice every year during the three cropping cycles. In the first ye ar, poultry manure did not perform better than urea but by the third y ear, when applied in quantities sufficient to supply 120 and 180 kg N ha(-1), it produced significantly more rice grain yield than the same rates of N as urea. Poultry manure sustained the grain yield of rice d uring the three years while the yield decreased with urea. Apparent N recovery by rice decreased from 45 to 28% during 1987 to 1989 in the c ase of urea, but it remained almost the same (35, 33 and 37%) for poul try manure. Thus, urea N values of poultry manure calculated from yiel d or N uptake data following two different approaches averaged 80, 112 and 127% in 1987, 1988 and 1989, respectively. Poultry manure and ure a applied in 1:1 ratio on N basis produced yields in between the yield s from the two sources applied alone. After three cycles of rice-wheat rotation, the organic matter in the soil increased with the amount of manure applied to a plot. Olsen available P increased in soils amende d with poultry manure. A residual effect of poultry manure applied to rice to supply 120 or 180 kg N ha(-1) was observed in the wheat which followed rice and it was equivalent to 40 kg N ha(-1) plus some P appl ied directly to wheat.