Root-shoot characteristics, yield and soil nitrogen status under different irrigation and nitrogen levels in maize (Zea mays L.)

Abstract

A field experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi, during
the rainy season of 2015 on sandy loam soil with maize hybrid PEEHM 5 to study the effects of
variable irrigation regimes and nitrogen (N) rates on root-shoot characteristics, yield and soil fertility
status. The experiment was laid-out in a three-time replicated split-plot design. The treatments
consisted of 24-combinations of 3-irrigation regimes: irrigation at 25% depletion of available soil
moisture (DASM), irrigation at 75% DASM and no-irrigation (rainfed condition) allotted to mainplots
and eight N-rates: control, 40, 80, 120, 160, 200, 240 and 300 kg N ha–1 to sub-plots. Irrigation
at 25% DASM resulted in significantly higher plant height at tasseling and maturity stages, dry
matter accumulation both at knee-high (KH) and tasseling stages, biological yield, harvest index
and soil available N compared to water-stressed conditions. However, water-stressed rainfed crop
recorded the highest root dry weight. With regard to N-effects, it was found that plant height, dry
matter accumulation measured at pre-and post-N top-dressing during KH stage increased upto
160 kg N ha–1, while at tasseling stage increase in these plant parameters was significant only upto
120 kg N ha–1. At KH stage 160 kg N ha–1, whereas at tasseling 120 kg N ha–1, recorded the highest
root dry weight. Treatment combination irrigation at 75% DASM and 300 kg N ha–1 recorded the
highest N-availability in soil.