Effects Of High Densities And Planting Patterns On Grain Yield And Straw Feeding Quality Of Summer Maize

The purpose of this study is to analyze the effects of high-density and planting methods on the yield and quality of summer maize,and provide basis for high-yield cultivation and efficient straw utilization of summer maize.In the present study two summer maize varieties(Zhengdan 958,Xianyu 335)were used as materials and two-element split-zone test design was used with 4 planting densities(75 000 plant/hm~2,90 000 plant/hm~2,105 000plant/hm~2,120 000plant/hm~2)as the main treatment,and two planting patterns(equal row,wide and narrow row)as the secondary treatment.A total of 16 treatments,three repetitions,were repeated for two years.By setting different planting densities and planting patterns,the photosynthetic characteristics,plant traits,yield and straw feeding quality of two summer maize varieties under different treatments were analyzed and evaluated.The main results were listed as follows:1.Effect of high density and planting mode on grain yield and quality of summer maizeThe response to density was consistent with the yield changes of two summer maize varieties.With the increase of planting density,the yield of single plant decreased significantly,but the population yield increased significantly with the increase of density.Under equal row planting patterns,the maximum grain yield of Zhengdan 958 was 14623.37kg/hm~2 under the plant density of 105 000 plant/hm~2,and the maximum grain yield of Xianyu335 was 14845.43 kg/hm~2 under the plant density of 120 000 plant/hm~2.While under wide and narrow row planting patterns,the maximum grain yield of Zhengdan 958 and Xianyu 335was respectively 13885.86 kg/hm~2 and 14036.87 kg/hm~2 under the same plant density of 120000 plant/hm~2.Grain yield of Zhengdan 958 under equal row were significantly higher than wide and narrow row methods except for 90 000 plant/hm~2 density with a increase of1.5%-2.5%.Compared to equal row methods,wide and narrow row increased 7.8%and 8.3%under 75 000 plant/hm~2 and 105 000 plant/hm~2 density,respectively.As the density increasing,the crude protein content of the two cultivars gradually decreased,and the crude fat content increased first and then decreased.2.Effects of High Density and Planting Methods on Photosynthetic Characteristics of Summer MaizeWith the increase of planting density,the canopy transmittance and net photosynthetic rate per plant of two summer maize varieties decreased significantly,and the photosynthetic pigment content decreased.At the same planting density,the net photosynthetic rate of plants in wide and narrow rows was 1.5%-19.6%higher than that of equal row spacing,and there was a significant difference trend.During the growth period,with the increase of planting density,LAI and LAD increased significantly,and promoted the population assimilation.High density planting conditions reduced photosynthesis of single plant maize,but improved photosynthetic rate effectively,which was an important reason for yield increase.3.Effect of high density and planting mode on the plant characters of Summer MaizeWith the increase of density,LOV of Zhengdan 958 gradually decreased.Xianyu 335 had an upward trend,and was higher than Zhengdan 958 under the same treatment,but the difference was not significant.Plant height,ear height,internode length,ear height coefficient increased first and then decreased.The high density reduced the panicle length,ear diameter,total grain number,1000-grain weight,and yield efficiency of grain,and increased the length of baldness,which in turn reduced the yield per plant.Plant traits were not conducive to yield per plant,but population yields increased.Planting density increased the group advantage to make up for the disadvantages of individual plants,so proper increase in planting densitywas a key factor in increasing production.4.Effect of high density and planting methods on straw feeding quality of summer maizeThe effects of density on the contents of CF,ADF,NDF,and hemicellulose were not significant but significantly different on CP.The CP content of Zhengdan 958and Xianyu 335increased first and then dropped significantly.Under the four density conditions,there exsited a relatively low fiber content and a high crude protein content under 105 000 plant/hm~2.Between planting methods,the difference was not significant,but wide and narrow row planting methods had lower ADF and NDF content than equal row,and therewas a high content of crude protein.Therefore,under the high-density planting pattern,Zhengdan 958was more suitable for wide and narrow row planting.