The Dry Matter Accumulation And Carbon And Nitrogen Metabolism Of Different Maize Varieties Under Different Nitrogen Application

Nitrogen played an important role in the maize growth; it’s the mostimportant element of the development and yield of maize. But maize itself didn’thad the function of nitrogen fixation, it had to absorb nitrogen from soil to grow,in that cases, farmers had to apply nitrogen fertilizers,which was not fullyabsorbed, to soil to meet the need of maize growth. Thus lead to a waste ofresources and great ecological impact. Under such circumstances, studying theimpacts of nitrogen in the process of maize growth, based on the characteristicsof nitrogen use of different maize to apply nitrogen fertilizers has greatmeanings. This experiment analyzed the dry matter accumulation and carbonand nitrogen metabolism of six maize varieties, the result was listed as follows:1、The dry matter accumulation of all maize varieties was increased afterapplying nitrogen fertilizers, but different maize was in different degrees ofsensitivity to nitrogen. The experiment showed that Tunyu99was more sensitiveto nitrogen compared to other maize varieties, while Xianyu335was lesssensitive.2、The impact of nitrogen was more obvious after silking stage, and as the amount of nitrogen applied in soil increased, the dry matter accumulationincreased, but that increase had a limit. After a certain amount of nitrogenapplication, the dry matter accumulation stopped increase, in some cases, it evenmay decrease.3、Photosynthetic carbon is a major component of the carbon content ofmaize grain kernel, in that case, insuring the leave photosynthetic capacity inlate growing period is the key to high yield. The rate of photosynthetic carbon inmaize grain kernel was different after nitrogen application. In this experiment,after nitrogen application the photosynthetic carbon in the grain kernel ofLuyu19was decreased. While the photosynthetic carbon in the grain kernel ofXianyu335and Tunyu19was changing differently under various level of Napplication. When N application rate was less than120kg and240kg per hm2,carbon transfer would increase; when application rate was140kg and210kgper hm2, the amount of photosynthetic carbon would increase.4、The nitrogen metabolism was more vigorous in Xianyu335. The nitrogenin grain kernel was mostly provided by roots. After N application, the rate ofnitrogen in grain kernel was increased.5、The carbon metabolism was more vigorous in Tunyu99and Luyu19. Inthe experiment of2013, the nitrogen in maize kernel was mostly provided by Ntransfer; when N was applied, the nitrogen provided by roots in maize kernelwould increase. But in the experiment of2014, the nitrogen in maize kernel ofthe two varieties was mostly provided by roots; after N application, the nitrogen provided by roots of Tunyu99was decrease; while the nitrogen in maize kernelof Tunyu19that provided by roots decreased in N application level of120kg perhm2, the nitrogen provided by roots in N application level of240kg per hm2wasless than in N application level of0kg per hm2and120kg per km2.