Effects Of Planting Patterns On Carbon And Nitrogen Accumulation, Translocation And Yield In Summer Maize Under Different Plant Densities

In order to explore the effects of planting patterns on carbon and nitrogen accumulation, translocation and yield in summer maize under different plant densities, a field experiments involving four planting patterns (three-row strip, four-row strip, five-row strip and a conventional uniform row spacing pattern (the control)) under two plant densities (67500and82500plants hm-2) with cultivar named’Zheng-Dan958’ were conducted in2011and2012to further explore the effect of strip planting patterns on carbon and nitrogen metabolism and grain yield in summer maize under different plant densities. Main results were as following:1. The effects of planting patterns on agronomic characters in summer maize under different plant densitiesCompared with control, the strip planting patterns obtained higher plant height and ear height, increased stem diameter and significantly decreased the2nd and3rd internode, which would enhanced plant lodging resistance under high density. Leaf angle of the1st leaf above the ear also decreased. The leaf angle of the1st and2nd leaf above the ear were less and the leaf orientative values were higher under the three-row strip than other strip plant patterns.2. The effects of planting patterns on carbon and nitrogen metabolism in summer maize under different plant densitiesUnder both high and low plant density, the Pn, Cond, Tr were all higher under all three strip planting patterns than under the control. Compared with control, the sugar accumulation of above ground, N accumulation of above ground in maturity stage increased by17.2%、15.0%、15.2%and16.2%、16.9%%20.0%under three-row strip, four-row strip and five-row strip cropping pattern, respectively, and the lowest C/N ratio in leaf at maturity stage was in the treatments of three-row strip under both low density and high density, while CK showed the highest C/N ratio in leaf.3. The effects of planting patterns on yield in summer maize under different plant densitiesBased on the Logistic equation fitting, the determination coefficient was high and the range was from0.9955to0.9996. The average filling rate, maximum filling rate value,100-grain weight of three-row strip were all higher under the three-row strip planting pattern than those under the other planting patterns. The grain yield was increased by strip planting patterns in both years, and the yields were16.7%,6.1%and 10.7%higher in2011and17.2%,12.1%and10.6%higher in2012under the three-, four-and five-row strip treatments, respectively, compared with the control. Among aH the treatments, the three-row strip planting pattern with a high plant density (82500plants hm-2) produced the highest grain yield in both years, and the yield was increased by25.0%,20.8%in2011and25.1%.18.7%in2012compared with that under low and high plant density of the control, respectively.Therefore, it could be concluded that the grain yield of summer maize could be enhanced by using a three-row strip planting pattern, especially under higher plant density.