Effects Of Nitrogen Management On Dry Matter Translation, Nitrogen Uptake And Soil Nitrate-nitrogen Accumulation Of High-yield Wheat

Field experiments with two typical wheat varities (Yumai49-198and LankaoAizao8) were conducted in Wenxian. Set240kg/ha to the optimal N rate(ONR),compared with25%(125%ONR)and50%(150%ONR) increase,25%(75%ONR)and50%(50%ONR) reduction, as well as no N (0N). In order to investigate the effects ofN management on the change of nitrate-nitrogen, dry matter accumulation, nitrogenuptake and utilization of High-yield wheat, and find a suitable N concentration of rootlayer. The main result was as follows:1.The soil nitrate-nitrogen of yumai49-198and lankao aizao8present aincreasing trend with the raise of N fertilizer application, there were significantdifferences between two years, but no significant differences between two wheatvarieties. Nitrogen treatment was significantly higher than0N, the soilnitrate-nitrogen significantly lower than ONR treatment with ONR increased orreduced25%and50%. The soil residual nitrate-nitrogen and N fertilizer applicationsignificant positive correlation after maturitying.2. Hydroponic wheat seedling root nitrogen concentration of wheat rootincreased significancly with the nutrient solution NO3–-N concentration in waterculture experiment, plant root dry weight and nitrogen accumulation first increasesand then decreases, root activity gradually reduced, stem sap nitrate content rapidincrease before gradually stabilized.75%ONR treatment with lankao aizao8wassignificantly higher than other treatments in the jointing and anthesising, Napplication had no significant difference between treatments in the maturitying; ONRwith yumai49-198increased or drop of25%, the root activity difference wassignificantly in the flowering, higher than150%ONR treatments, the ONR wassignificantly higher than other treatments in the maturitying.3. Population of wheat reached the maximum in the jointing, and then began todecline rapidly, the ONR reduced by25%, an increase of25%and50%, populationbetween the treatment was no significant difference in the jointing; ONR reduced by50%between the treatment groups significantly different. Dry matter accumulationgradually increased as the growth period extension from wintering to jointing, dry matter accumulation rate of increase lower dry matter accumulation rate of increase ishigh in the jointing; N treatment was significantly higher than without N treatment,ONR increase of25%and50%, the difference between treatments was notsignificant.DMT (dry matter translocation), DMTE (dry matter translocationefficiency) and DMTP (dry matter to grain contribution rate) of hull rachis of yumai49-198and the Lankao Aizao8are negative, the stems, leaves, sheath and hull rachisof DMT, DMTE and DMTP in nitrogen application rate is higher than the ONRtreatment difference was not significant, the order of the DMT and DMTP:stem>leaf>sheath, the order of DMTE: leaf>stem>sheath, different between the yearand varieties.4. The N concentration of straw of yumai49-198and Lankao Aizao8firstgradually increasing with the growth advancement, achieved maximum in the jointingor at anthesising, and then decreased rapidly. Nitrogen accumulation gradualincreased with the growth advancement, these was little difference of nitrogenaccumulated of two varieties in the same year, but difference in amount between thesame species are different in the two-year trend, the nitrogen concentration and trendwas closely related.Stems, leaves and the nitrogen the transshipment total beforeanthesising with increasing amount of nitrogen have shown for the first increase inmore than a certain amount of difference between treatments was not significant; thetreatments of assimilation nitrogen after anthesising no significant differences. Theorder from largest to smallest of storage of nitrogen and transferred to the grainnitrogen contribution rate before anthesising of two different varieties and organs in2009~2010was: leaves> hull rachis> stems> sheaths,2010~2011order was: leaf>stem> sheath> hull rachis.5. The production and production rate of yumai49-198and Lankao Aizao8of75%ONR was the highest in2009~2010, while production increased gradually withincreasing of N fertilizer application in2010~2011,150%ONR was the highest, thepanicle number and lernels perear no significant increase if N fertilizer more than75%ONR level, sink capacity and the grain yield of wheat was a significant positivecorrelation.6.N uptake efficiency, N utilization efficiency, utilization of N in this season, PFP,N agriculture efficiency, N physiological efficiency reduced with increasing Nfertilizer application. There are little differences between varieties of apparentnitrogen mineralization content, but big differences between year; N apparent loss increased if N fertilizer application was higher than ONR; N surplus increasedsignificantly with increasing of N fertilizer application, show index, excessivefertilizer would create a huge N loss and residual soil.7. Taken together, returning-jointing stage and jointing-anthesising stage was acritical period of wheat growth, but also a critical period of nitrogen management. Toachieve optimum yield and optimum N rate to take into account the environmentshould be180~255kg/hm~2.0~30cm soil suitability soil nitrate nitrogen concentrationrange was57~88kg/hm~2in wintering,0~60cm soil suitability soil nitrate contentrange of89~109kg/hm~2in returning,0~90cm suitability soil nitrate content rangeswere125~141kg/hm~2,104~143kg/hm~2,127~159kg/hm~2in jointing, anthesising,maturitying.