Abstract
Potassium (K) as a macro nutrient governs important physiological mechanisms ensuring optimum plant growth and produce quality. An experiment was conducted during the summer of 2017 to study the effects of potassium application on maize under high nitrogen (N) nutrition with optimum and reduced irrigations. The experiment was comprised of three factors, viz. two irrigation levels (optimum, reduced), three potassium levels (80, 120 and 160 kg ha(-1)) and four nitrogen levels (100, 150, 200 and 250 kg ha(-1)). Two separate trials were carried out in randomized complete block design (RCBD), one under optimum (five irrigations) and another under reduced irrigation (three irrigations). One control plot (OK, ON) was used under each replication for both trials. Optimum irrigation had resulted in maximum days of tasseling, silking, physiological maturity, crop growth rate (CGR), net assimilation rate (NAR), absolute growth rate (AGR), plant height, grains ear', thousand grains weight, biological yield, grain yield, chlorophyll contents and shelling percentage. High N (250 kg ha(-1)) delayed tasseling, silking and physiological maturity and resulted in maximum growth, physiological traits and biological yields. However, 150 kg N ha(-1) had resulted in maximum number of ears ill 2 , number of grains ear(-1) , thousand grains weight and grain yield. While 100 kg N ha(-1) had resulted in early tasseling, silking and physiological maturity. Potassium fertilization at the rate of 160 kg ha(-1) delayed phenology and recorded with maximum growth rates, improved physiology and maximum yield traits and grain yield. However, the treatment 120 kg K ha(-1) remained almost statistically similar to the 160 kg K ha(-1) for most of the parameters. In the case of control vs rest, generally the performance of the control plot was poor. Hence, 150 kg N ha(-1) with 120 kg K ha(-1) under optimum irrigation is recommended for optimum productivity of maize crop.