| This reasearch which is based on completely mulched alternating narrow and wide ridgesconsists of two experiments with treatment of different nitrogen rates and planting density onsemi-arid rain feed agricultural region in the year2012and2013. There are four different nitrogenrate treatments that include0kg/hm2(N1),100kg/hm2(N2),200kg/hm2(N3) and300kg/hm2(N4),and four planting density treatments that include45000plants/hm2(T1)、52500plants/hm-2(T2)、60000plants/hm2(T3) and67500plants/hm2(T4),the tested variety is Funong821. This researchstudy the impact of planting density and nitrogen rate on the growth and formation of foragequality of foodstuff maize under completely mulched alternating narrow and wide ridges withfurrow planting, through measuring and analyzing the leaf area of whole growth period, drymatter of each organ, crude protein in stalk, leaf and sheath, contents of acid detergent fiber(ADF)and neutral detergent fiber(NDF). Here are the results:1、 The leaf area index of foodstuff corn in2012and2013increases significantly as nitrogen raterises, the leaf area index in whole growth stage under application level300kg/hm2is lager thanthat under other levels. The leaf area index increases as planting density increase.2、 Dry matter accumulation in leaf, sheath and stalk of corn is highest in the milk stage.Accumulation of dry matter in all organ in milk stage under N4treatment rise by717kg/hm2、698kg/hm2and696kg/hm2than that under N1treatment with no nitrogen application in2012. In2013, Accumulation of dry matter in all organ in milk stage under N4treatment rise by1834kg/hm2,197kg/hm2and756kg/hm2than that under N1treatment. The increment in leaf, sheathand stalk under different planting density in milk stage and ripening stage are1834kg/hm2and1718kg/hm2,215kg/hm2and170kg/hm2,756kg/hm2and771kg/hm2.3、 Contents of chlorophyll increases as application of nitrogen increases, and reaches themaximum in filling stage. Contents of chlorophyll under N4treatment increase by16.74SPADand12.2SPAD than that under N1and N2treatment, and reaches the maximum in filling stageunder different planting density, this value under T1treatment increase by2.72SPAD and5.5SPAD than that under T3and T4treatment. Content of chlorophyll decreases after filling stage.4、Increasing the nitrogen application amount and decreasing the planting density could reducedthe ADF content in different growth stages and improve the corn feeding quality. As the increased nitrogen application amount in cropland in2012,the ADF content in corn of different growthstages was significantly decreased gradually. The pure ADF content in leaf, sheath and stalk inmilk stage under N4treatment decreased by2.4%,2.5%and3.02%than that under N1treatment,respectively. The yield of ADF under N4treatment increased by97kg/hm2、184kg/hm2than thatunder N1treatment, though that in stalk decreased by11kg/hm2. In the ripening stage, ADFcontent in leaf, sheath and stalk under N4treatment decreased by2.33%,1.53%and3.24than thatunder N1treatment, yield of ADF increased by97kg/hm2and47kg/hm2，and that in stalkdecreased by97kg/hm2.The order of ADF content in stalk, leaf and sheath is sheath>leaf>stalk.In2013, the ADF content in stalk, leaf and sheath in milk stage under N4treatment decreased by3.52%、1.9%、3.34%, yield of pure ADF increase by143kg/hm2,72kg/hm2and189kg/hm2. Inthe ripening stage, the pure ADF content decreased by2.95%,2.8%and1.4%, the yield increases.The ADF content in leaf, sheath and stalk in milk stage under T1treatment decrease by4.5%,5.4%and4.2%, and yield of that increase gradually.5、The variation trend of NDF in different organs in all growth stage is same under differentnitrogen application treatment in2012and2013. In2012, the content of NDF in ripening stageunder N4treatment increase by3.56%,3.2%and3.23%, the yield of NDF increase by1336kg/hm2,74kg/hm2and93kg/hm2. In2013, the NDF in leaf, sheath and stalk in milk stage underN1treatment decrease by2%,5.4%and3.48%, yield of NDF increase by394kg/hm2,76kg/hm2and527kg/hm2。NDF content in ripening stage under N1treatment decrease by3%,3.49%and4.22%, yield of NDF increase by400kg/hm2,210kg/hm2and505kg/hm2. When under differentplanting density treatment, NDF content under T1treatment decrease by0.9%and3.5%than thatunder T2and T4treatment in postulation period, and decrease by1.85%and3.28%in milk stage.6、Increasing the nitrogen application amount could improve the content of CP in corn andimprove the quality for corn. CP content in leaf in milk stage under N3and N4treatment increaseby1.56%and2.1%than that under N1treatment, the pure CP content increased by122kg/hm2and196kg/hm2. CP content in ripening stage under N3and N4treatment increase by1.92%and2.59%than that under N1treatment, the pure CP content increased by284kg/hm2and375kg/hm2.In the sheath, CP content under N4treatment increase by0.68%than that under N1treatment,yield of CP increase by34kg/hm2in milk stage. CP content under N4treatment increase by0.67%than that under N1treatment, the pure CP content increased by18kg/hm2in ripening stage. When treated by different planting density, content of crude protein in leaf under T1treatmentincrease by0.85%and1.38%than that under T3and T4treatment in milk stage. Content of crudeprotein insheath under T1treatment increase by0.76%and1.08%than that under T3and T4treatment in milk stage. content of crude protein in sheath under T1treatment increase by0.63%and1.11%than that under T3and T4treatment in ripening stage.After the study of effect by different nitrogen rate, in the range of0-300kg/hm2. the feedingquality and forage quality increased as the nitrogen application increase. Economic yield andbiological yield are the highest when planting density is52500plants/hm2,and the forage qualitydecreases significantly under treatment67500plants/hm2, the planting density kept between52500plants/hm2and60000plants/hm2.and nitrogen application rate at300kg/hm2is better forimproving the quality of foodstuff maize under completely mulched alternating narrow and wideridges with furrow planting. the nitrogen application amount in300kg/hm2. |
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