Dp. Sherchan et al., Response of wheat-rice and maize/millet systems to fertilizer and manure applications in the mid-hills of Nepal, EXP AGRICUL, 35(1), 1999, pp. 1-13
Farmers in the mid-hills of Nepal have a mix of rainfed land on which mille
t is grown in relay after maize (maize/millet), and irrigated land on which
wheat is grown sequentially after rice (wheat-rice). Double cropping is th
e norm but the diminishing quantities of organic materials, coupled with th
e trend towards increased use of inorganic fertilizers, have raised questio
ns about the long-term productivity and sustainability of the cropping syst
ems. The aim of this work was to examine the long-term effects (eight years
) on grain yield of additions of manure and fertilizer either singly or in
combination. Maize/millet and wheat-rice rotations were established on a Dy
stochrept at Pakhribas Agricultural Centre at about 1450 m altitude. Manure
and fertilizer applications were applied to the maize (eight combinations
in May) and the wheat (different rates in seven combinations in November) e
very year with the succeeding crops (millet and rice) utilizing residual nu
trients. Yields of maize, millet and rice were greater when manure rather t
han fertilizer was applied but yields of wheal were less. The combined appl
ication of manure and fertilizer significantly increased yields of maize an
d wheat compared with applications of either manure or fertilizer alone. Ho
wever, for the subsequent crops (millet and rice) there was either a small
residual benefit of the combined application when compared with fertilizer
alone, or no benefit when compared with manure alone. Overall, the combined
application increased total grain yields by about 35% in the maize/millet
rotation and by 16% in the wheat-rice rotation. There was no trend in yield
s in response to treatment with time.