The effects of planting patterns and densities on photosynthetic characteristics and yield in summer Maize

Abstract

In China, maize (Zea mays L.) is the third most important cereal crop, after wheat and rice, and is used as a staple food for humans, livestock and as raw material for many industrial products. The Huang鄄Huai鄄Hai Plain is the most important maize production region; however, in recent years, during the maize growing season, especially during the pollination period, extreme weather, such as heat waves and overcast or rainy weather, has frequently occurred in this area. These weather events seriously reduced maize plant biomass and grain yield for the current conventional uniform row spacing pattern, especially with an increased plant density. Crop row spacing can influence the canopy architecture, and optimal row spacing can improve the group structure, increase sunlight penetration, reduce competition between strains, and promote the individual plant growth, which contributes to a high biomass and maize yield. The objective of this study is to further explore the effects of planting patterns combined with plant densities on the photosynthetic characteristics of summer maize. Field experiments involving four planting patterns (three鄄row strip, four鄄row strip, five鄄row strip and the control conventional uniform row spacing pattern) under two plant densities(67500 and 82500 plants / hm 2) , using the ' Zheng鄄Dan 958爷 cultivar were conducted in 2011 and 2012 in this region. Under both high and low plant densities, compared with the control, the strip planting patterns decreased the leaf angle of the 1 st leaf above the ear, and the leaf angles of the 1 st and 2 nd leaves above the ear were smallest under the three鄄row strip pattern. The SPAD value of ear leaves was significantly influenced by treatments in both years at the flowering stage and in 2012 at the maturity stage. At flowering stage, the SPAD