Effect of row width and plant population density on yield and quality of maize (Zea mays) silage

Abstract

The study reported in this thesis was conducted during 2015/2016 at Lincoln University, New Zealand, to investigate the effect of row width and plant population density on yield and nutritive quality of maize silage (Pioneer Hybrid P7524). A Randomized Complete Block Design was used. The main treatments were row widths (0.76m and 0.38m) whilst the sub-treatments were intra-row spacings (0.12m, 0.18m and 0.24m), giving a total of six plant population densities (54,824, 73,099, 109,649, 146,198 and 219,298 plants/ha) with four replicates each. The crops were harvested at 30-35% DM and ensiled in PVC type silo for 100 days. Grain, DM and stover yield per unit area increased significantly with increasing plant population due to increasing radiation interception. However, low leaf chlorophyll concentration was also found to reduce grain and DM yield in spite of high radiation interception. Also, at constant or same intra row spacing, the 0.38m row width recorded percentage grain increases of between 78.6% and 127.6% which were almost twice or more compared with the 0.76m row width. Increasing plant population also increased leaf chlorophyll concentration of plants during the initial stages of plant growth and development. Plant population density and row width did not have any significant impact on the nutritive value of maize silage.