LIGHT INTERCEPTION, RADIATION USE EFFICIENCY AND BIOMASS ACCUMULATION RESPONSE OF MAIZE TO INTEGRATED NUTRIENT MANAGEMENT UNDER DROUGHT STRESS CONDITIONS

In order to alleviate the drought adversities on maize (Zea mays L.)biomass accumulation and radiation use efficiency (RUE), a field study was conducted under drought stress levels of D-1 = well-watered, D-2 = drought stress at blister stage, D-3 = drought stress at blister and dough stages; and integrated nutrition levels, N-0 = control, N-1 = NPK, 125-60-62 kg ha(-1), N-2 = NPK, 125-60-62 kg ha(-1) + FYM at 10 t ha(-1), N-3 = NPK, 125-60-62 kg ha(-1) + FYM at 15 t ha(-1), N-4 = NPK, 250-120-125 kg ha(-1), N-5 = NPK, 250-120-125 kg ha(-1) + FYM at 10 t ha(-1), N-6 = NPK, 250-120-125 kg ha(-1) + FYM at 15 t ha(-1). Drought stress caused a significant decline in growth traits, interception of photosynthetically active radiation (PAR), RUE and finally biomass production. The highest leaf area index, leaf area duration, crop growth rate, net assimilation rate, interception of PAR and dry matter accumulation was recorded in plants applied with NPK (250-120-125 kg ha(-1)) in combination with FYM (15 t ha(-1)), whereas only NPK application did not significantly improve light interception and dry biomass production. Fraction of intercepted (Fi) radiation was significantly improved by integrated nutrient management under well-watered as well as drought stress conditions. A substantial decrease in total dry matter and grain yield basis RUE was recorded from higher to lower plant nutrition rates, as the highest value of RUE was found with treated plants of 250-120-125 kg NPK ha(-1) + FYM at 15 t ha(-1). Thus, our study demonstrates that supplemental NPK with FYM is an effective strategy to boost the drought tolerance through improved RUE and biomass accumulation in maize.