Effects Of Nitrogen Fertilizer And Planting Density On Lodging Resistance Of Spring Maize In High-Fertility Soil

High-density high-yield mechanized production of corn planting is the core element of modern corn production technology.However,close planting could change the ecological environment of maize group,and then result in lodging,which is the main factor limiting mechanized production of maize.Jilin province is the golden belt for corn cultivation in China and is an important national commodity grain base,and a significant area to promote high-density high-yield mechanized production of corn.Therefore,studying anti-lodging mechanism in high-density here is meaningful.The experimental materials of this study were Xiongyu 581in 2016,and Hongyu236,Xiangyu 998 and Jiamei 2 in 2017.Split plots were designed in the field experiments.In 2016,the main block was density treatment and the second block was nitrogen fertilizer rate.The density setting were:64000,75000,85000,90000,and 95000 plants per hectare,respectively.The nitrogen application level were 150,180,210,and 240kg/hm~2,respectively.In 2017,the main block was nitrogen application,and the second block was density.The density setting were 60000,70000,80000,90000,and 100000 plants per hectare,respectively.The nitrogen application level were 150,180 210 240,and 270kg/hm~2,respectively.The lodging-related morphology,dry matter,and mechanical characters of stalk were measured in this study.The main results were as following:1.The results of morphology traits showed that:The ear height coefficient and the stem diameter coefficient increased with increasing density,and the influence of nitrogen application was insignificant.When planted in 60000~70000 plants per hectare with nitrogen fertilizer of below 210kg/hm~2,the maize group could have lower ear height coefficient and higher stem diameter coefficient,which cloud lead to greater lodging resistance.Among these four experimental materials,Hongyu 236had better performance in the two indexes.2.The results of dry matters showed that:The dry weight of whole plant decreased obviously with increasing density,and the impact of nitrogen application was insignificant.Dry matter per centimeter of inferior inter-nodes was more than that of upper inter-nodes.Moreover,the variation trend of dry matter per centimeter of inter-node was same as dry weight of whole plant when the density or nitrogen application changed.When planted in 60000~80000 plants per hectare with nitrogen fertilizer between 210~240kg/hm~2,the maize group could have greater dry weight of whole plant and dry matter of inter-nodes,which could lead to greater lodging resistance.3.The results of physiological traits showed that:The content of crude fiber decreased with increasing density.Increasing nitrogen application under low density or fertilizing less nitrogen under high density could both result in higher content of crude fiber.The interaction of density and nitrogen application for content of crude fiber showed as that low density with low nitrogen application could lead to high content of crude fiber.For the content of N,fertilizing less nitrogen under low density or increasing nitrogen application in a certain range under high density could lead to higher N content.In addition,for the content of K,when planted in 80000plants per hectare,the corn could have higher K content.Increasing nitrogen application was also helpful for K content.The interaction of density and nitrogen fertilizer showed as that N content could higher under low density with low nitrogen application and K content could higher under high density with high nitrogen application.4.The results of correlation showed that:There are mainly 5 indexes that had significant correlation with stalk push-down strength,and they are dry weight of whole plant,the ratio of female spike dry weight for whole plant dry weight on tasseling stage,the ratio of leave dry weight for whole plant dry weight on tasseling stage,node dry weight per centimeter of 3~rdd to 5~thh node and crushing strength of 3~rdd node respectively.The most related node is different for different varieties,but the3~rdd node showed significant correlation with push-down strength for all the experimental varieties.In summary,density is the main affecting factor for the lodging-related traits of maize planted in high-fertility soil,but applying the matched level of nitrogen fertilizer can also have impact on these traits.And for different maize variety,the interaction of density and nitrogen fertilizer is different.In this study,the lodging resistance of Hongyu 236 under is the best.And when it was planted in density of80000 plants per hectare with nitrogen fertilizer 210~240kg/hm~2,the traits related to lodging resistance and the production are both great.