Impact of potassium rates and their application time on dry matter partitioning, biomass and harvest index of maize (Zea mays) with and without cattle dung application

Abstract

Two field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to potassium (K) levels (30, 60, 90 kg ha -1) and K application time (T 1 = full at sowing, T 2 = full at V9 stage (many ear shoots were easily visible upon dissection), and T 3 = 50% each at sowing and V9 stage with and without cattle dung. One experiment was carried out in the field where 5 t ha -1 cattle dung was applied (15 days before sowing), while the field under second experiment received no cattle dung (0 t ha -1). The research was carried out at the Agronomy Research Farm of The University of Agriculture Peshawar during summer 2014. The experiments under both treatments were laid out in randomized complete block design using three replications. The results revealed that the K treated plots (rest) under both treatments had produced more number of leaves plant -1 and mean leaf area, partitioned more dry matter into various plant parts (leaf, stem and ear), and produced more biomass yield and harvest index than control (K not applied). Cattle dung was found more beneficial in terms of more number of leaves plant -1, higher mean leaf area, partitioning of more dry matter into leaf, stem and ear, and producing higher biomass yield and harvest index as compared to the treatment that received no cattle dung. Increasing the rate of K increased number of leaves plant -1 and mean leaf area, partitioned more dry matter into various plant parts (leaf, stem and ear), produced more biomass yield and harvest index and vice versa (90 kg K ha -1 60 kg K ha -1 30 kg K ha -1). Increase in number of leaves plant -1, mean leaf area, dry matter partitioning into various plant parts (leaf, stem and ear), biomass yield and harvest index was observed when K was applied in two equal splits (50% each at sowing and V9 stage > 100% at sowing > 100% at V9 stage). It was concluded from this study that application of K at the highest rate of 90 kg ha -1 in two equal splits (50% at sowing + 50% at V9 stage) along with cattle dung (5 t ha -1) could improve number and area of leaves, dry matter partitioning, biomass yield and harvest index under limited irrigation condition.