Response of Maize Forage Yield and Quality to Nitrogen Fertilization and Harvest Time in Semi−arid Northwest China

Abstract

Aim: Maximizing the soil nutrient of grain and forage maize production is vital to guarantee enough grains and fodder supply to meet the human and livestock demand. This study was done to investigate the effect of nitrogen fertilization and harvest time on growth, yield and quality of fodder maize (Zea mays L.). Study Design: The experimental design was a randomized complete block design with four treatments replicated three times. Place and Duration of Study: Field experiment was conducted in 2014, 2015 and 2016 cropping seasons at the Dingxi Experimental Station, Gansu Province Northwest China. Methodology: The treatments were fertilizer rates applied planting at 0. 100, 200, and 300 kg ha-1 (referred to as N0, N100, N200, and N300, respectively).  Results: It was found out that N300 treatment increased forage yield at 60 days after sowing (DAS) (by 127, 48 and 15%), at 90 DAS (by 83, 45 and 16%), at 120 DAS (by 78, 41 and 13%) and at 153 DAS (by 86, 46 and 14%) as compared to N0, N100 and N200 respectively. Application of N300 increased grain yield by 79, 56 and 8% compared to N0, N100 and N200 respectively; and also increased crude protein (%) across years and growth stages, respectively, by 42, 19 and 3%. At a lesser magnitude, application of N200 also increased forage and grain yield compared to N0. Acid detergent fibre and neutral detergent fibre was decreased with N fertilization (i.e., N100, N200 and N300) compared with N0, which consequently increased relative feed value. Conclusion: From this study, N300 treatment appear to be the optimal rate of N fertilization for improved forage yield and quality of maize in the semi−arid Loess Plateau.