Study Of Environmental Effect In Wheat Yield And Quality Formation And Nutirent Highly Efifcient Utilization

This paper is composed of two parts.The first part studied the effects of tillage practice and nitrogen rate on nitrogen use efficiency andyield, quality of wheat. In growing seasons of2008-2010, the experiment was carried out in ChifengCity, Inner Mongolia Autonomous Region, which belongs to arid and semi-arid region, Farming-PastureZone of north China. The experiment compared the effect of tillage and nitrogen use efficiency onwinter wheat yield and quality as well as nitrogen absorption and utilization in winter "wheat-soil"system.The second part studied the effects of different eco-environments and cultivation measures on grainFe, Mn, Cu and Zn contents and quality and yield in wheat. Experiments were carried out at threelocations (experimental station of the Institute of Crop Sciences,Chinese Academy of AgriculturalSciences; Yuanzhong Farm in Renqiu,Hebei Province;experimental station of Zhaoxian,HebeiProvince) in growing seasons of2009-2011. We studied the effects of the genotype, environment andcultivated measures such as nitrogen application rate, nitrogen topdressing ratio and nitrogentopdressing stage on the micronutrient concentration in grains and quality and yield in wheat.TheVarieties were Jimai20, Wanmai38, Jingdong8and Zhongmai8.The main results are as follows:1. The research showed that long-term implementation of conservation tillage was propitious tonitrogen absorption of winter wheat as well as increased grain yield, protein content and processingquality. With the increase of nitrogen application rate from120kilograms per hectare to360kilogramsper hectare, nitrogen use efficiency of winter wheat dropped from36.5%to26.1%; with about anincrease of every5percentage point of nitrogen loss, the nitrogen loss increased from60kilograms perhectare to200kilograms per hectare accordingly, which caused more severe environmental pollution.After wheat cultivation for two seasons, the proportion of total nitrogen recycled through "wheat-soil"system was about44%-50%; the proportion of nitrogen residues in the soil was about13%-18%.Thehigher nitrogen application rate in the last season was, the lower nitrogen use efficiency of winter wheatwas and the more nitrogen loss would be.2. The effects of environment were significant on the micronutrient concentration in grains andquality and yield in wheat. Different experimental points yield differences can reach2000kg/ha and thedifference among protein can reach1.5percentage point. The difference of grain Fe, Mn, Cu and Zncontents are respectively4.04mg/kg,4.20mg/kg,0.78mg/kg and6.55mg/kg. The results show that underthe sufficient condition of trace element content in soil, the changes of the micronutrient concentrationin grains and in various experimental points soil are different. There were significant differences ofgenotypes. The yield, quality and micronutrient content are different in different years. The results showthat the environment, meteorological condition and their interaction can affect the grain yield andquality. 3. The effects of nitrogen application rates were significant on yield and kernel traits. With theincrease of nitrogen application yield has increased first and then reduced. The nitrogen fertilizationcould significantly increased development time, stable time, sedimentation, wet gluten, dry gluten andbaking quality. The nitrogen fertilization is beneficial to promoting the absorbing ability of wheat to Fe,Cu and Zn, but it was not beneficial to the accumulation of Mn. To obtain high yield point of view,combined with wheat quality,the optimum cultivation measurement was N fertilizer180to270kg/hm2.The change of nitrogen topdressing stage has not significant effect on yield, protein and processingquality. With postponing topdressing time of N fertilizer, the contents of grain Mn, Cu and Znsignificantly increased, while the contents of Fe decreased. With the increasing of nitrogen amount fortopdressing, the yield and sedimentation enhanced first, and then decreased. With the increasing ofnitrogen amount for topdressing, the protein content, grain content of Cu development time, stable time,water absorption, gluten index, rigidity and baking quality significant improved.4. Studies on varieties stability and application of nitrogen (N) fertilizer shows that ecologicalenvironment impacts the great variance of traits include yield, grain content of Zn, development timeand stable time. The variation coefficients are larger than10%. The yield, rigidity, development time,stable time and sedimentation variance among years, while there are some differences among varieties.5. Nitrogen (N) fertilizer has various degrees of moderating effects on grain yield and quality.Proper application of nitrogen fertilizer is beneficial to reducing the difference about yield, graincontents of Fe, Mn, Zn among different varieties, to increasing the grain content of Cu difference.Properapplication of nitrogen fertilizer could reduce the protein content difference among different varieties,while over-application of N fertilizer May increase their differences. Nitrogen fertilizer has differentdegrees of compensation effect to the effects of environment on grains yield and quality. Application ofnitrogen fertilizer could increase the yield and protein stability, Proper application of nitrogen fertilizecould decrease the difference of Fe and Cu contents among experimental points, while bothover-application and less-application nitrogen fertilizer go against the stability of grain contents of Mnand Zn.In conclusion, the characters greatly influenced by nitrogen application rate are grain yield, stabletime, development time and sedimentation. Those characters are sensitive to nitrogen fertilizer. Nitrogenfertilizer has compensation effect to the effects of environment on grains yield and quality. Theoptimum cultivation measurement was N fertilizer180to270kg/hm2.6. Postponing topdressing time of N fertilizer is beneficial to reduce the differences of grain yieldand processing quality among varieties. Application of nitrogen fertilizer in early stage could reduce thedifference of grain yield and processing quality among experimental points and increase the wheatstability among sites.7. Increasing of nitrogen amount for topdressing is beneficial to decreasing the differences amongvarieties about grain yield, development time, stable time, sedimentation, dry gluten and the graincontent of Cu. It has little effect of baking quality. There are minimum differences among varietieswhen the base fertilizer to topdressing as5:5. Increasing of nitrogen amount for topdressing is beneficial to reduce the differences of grain yield, protein content, water absorption, development time, breadvolume, bread score and the grain content of Fe among experimental points. Decreasing of nitrogenamount for topdressing is beneficial to reduce the differences of the grain content of Cu, stable time, wetgluten, sedimentation, dry gluten among experimental points.