Effects Of N Management On Population Quality And Yield Of Winter Wheat In Cold Area

A plot experiment was designed with three optimization fertilization treatments(OPTs) and a farmer's fertilization practice to study the effects of N managemengt on population quality,dry matter accumulation,NPK uptake patterns and yield of winter wheat in cold erea. The main results are as follows:Compared with CK, OPTs reduced the total N application rate by 38.1%. OPT1 significantly increased earbearing tiller rate( reached 59.7%);maximum LAI appeared at heading stage, reached 2.55;significantly increased grain to leaf area ratio,which was positively correlated with yield (P<0.01);earbearing tiller rate was positively correlated with grain weight (P<0.01) and yield (P<0.01).OPT1 significantly increased biomass of winter wheat,upto 9.28 t/hm2. The fastest period of dry matter accumulation rate was from jointing stage to heading. OPTs significantly increased dry matter accumulation after heading,significantly increased the dry weight of the panicle,and significantly improved the distribution ratio in panicle, and harvest index. Dry matter accumulation before jointing stage was positively significant conic with yield, and dry matter accumulation after heading was positively correlated with yield.N content in leaf is the highest at early growth stage of winter wheat,and the highest was in grain at late growth stage. N content in grains is not associated with N application rates. But OPTs could significantly increase N content in grains. At maturity,N accumulation achieved peak value. The fastest period for N accumulation was from jointing stage to heading. At maturity,the distribution proportion accounts for more than 80% in panicle. OPT1 significantly increased N accumulation after heading, and increased the distribution proportion of N in panicle.The N uptake rate and translocation after jointing cohld be significantly increased through topdressing N fertilizer at jointing stage.Through topdressing N fertilizer at jointing stage,to promote N translocation. N accumulation before jointing stage was positively significant conic with yield, and N accumulation after heading stage was positively correlated with yield.P accumulation pattern is the same with N in different periods and organs. At maturity,P accumulation achieved peak value. From jointing stage to mature is absorb peak. At maturity,the distribution proportion accounts for more than 88% in panicle.OPT1 significantly increased P accumulation after heading, increased the distribution proportion of P in panicle and increased translocation amount of vegetative organs. P uptake rate after jointing cohld be significantly increased through topdressing N fertilizer at jointing stageK content in stem is the highest in the whole growth period. At heading stage,K accumulation achieved peak value. At maturity, the distribution proportion accounts for 25% in panicle, lower than N and P. OPT1 significantly increased K accumulation.Compared with the CK, the yield of OPT1 increased by 37.6 %(P<0.01), reached 5.14 t/hm~2; panicle number increased by 15.5%(P<0.05), reached 400×10~4/hm~2; 1000-grain weight increased by 17.5%(P<0.01), reached 35g; PFP increased by 140.7%(P<0.01); harvest index and N harvest index were inproved as well.