Abstract:
The objective of this study was to investigate the
effects of addition of pulses in crop
sequences, crop residue management, and application
of fertilizer N on soil nitrogen
content, soil organic carbon, nutrient uptake, and
its consequences for wheat yields. The
field experiments were carried out from 2009 to 201
2 in the sub-humid and sub-tropical
zone of northern India. The treatments were (i) cro
p residue retained (+Residue) or (ii)
removed (-Residue), (iii) 120 kg N ha
-1
applied to wheat, (iv) 150 kg N ha
-1
to maize, and
(v) a control with no nitrogen applied to either wh
eat or maize. The cropping systems
consisted of a rotation of wheat and maize or wheat
and green gram. Postharvest
incorporation of crop residues significantly (P< 0.
05) increased the wheat grain and straw
yields during 2010-2011 and 2011-2012. On average,
crop residues incorporation
increased the wheat grain yield by a factor of 1.31
and straw yield by 1.38. The wheat
crop also responded strongly to the previous legume
(green gram); grain yield increased
by a factor of 1.89 and straw yield by 2.05, compar
ed to the control. Application of
fertilizer N to the preceding maize crop exerted a
strong carryover effect on grain (1.18)
and straw yield (1.26) wheat. Application of N fert
ilizer to wheat increased grain and
straw yields by, respectively, a factor of 1.69 and
1.79 on average. The overall conclusion
is that an improved crop residue management, combin
ed with application of fertilizer N
or incorporation of legumes greatly improves the N
economy of cereal cropping systems
and enhances crop productivity in soils with a low
N content on the short term.
Keywords:
Crop rotation, Legume, Maize, Organic carbon.
