Effects Of Cultivation Management Models On Dry Matter Production And Nitrogen Use Effeiciencv Of Winter Wheat

In order to explore the optimization cultivation management model andachieve the high target yield and strong efficiency in winter wheat, four cultivationmanagement models including the current pattern of traditional farmers model (FM), theadjustment model1(AM1),the adjustment model2(AM2) and the adjustment model3(AM3)were conducted to study the effects of different cultivation management modes on soilmoisture and nitrate-nitrogen dynamics in wheat field, grain yield formation, carbonmetabolism, material production and nitrogen assimilation under the conditions of fieldexperiment at Wen County in Henan Province during2009-2011. The main results were asfollows:1. Migration and change dynamics of soil moisture and nitrate in different cultivationmanagement models of winter wheatSoil moisture increased while nitrate decreased with the deepening of soil layer indifferent cultivation management models. Compared with the current pattern of traditionalfarmers model (FM), in the adjustment models soil moisture in different layer were lowerbefore winter stage and regreening stage than jointing stage. It fitted that the wheat has a largedemand for water in the jointing stage. Because a large amounts of nitrogen used as bottomapplication in traditional cultivation and management model, it’s content of nitrate-nitrogen indifferent soil layers were higher in the winter period and the regreening stage than. While theadjustment models fertilized both as bottom application and in jointing stage, so thenitrate-nitrogen contents were high in the jointing stage and the flowering stage in all layer. Itmeets the demand of nitrogen in grain filling and spike flower development.2.Effect of different cultivation management models on yield formation of winter wheatThe experiment result showed that, the dynamics of young panicle development werelittle difference among the various models in the winter and regreening stage; the youngpanicle development significantly accelerated post-jointing, compared with the current patternof traditional farmers model. Different ear florets had different development process. Thefastest was the floret locations in the ninth spikelet, the second was the third spikelet, the slowest was the top spikelet. The peak of young panicle development approximately was onthe21th day after jointing stage; AM2had the highest total number of florets and the mostperfect floretsThe experiment results showed that, AM2had the highest grain yield two years. From theyield component analysis, there were more spikes in FM than others, but the grain number perspike and the grain weight were significantly lower than other models so that the yield wassignificantly lower than adjustment models. There were more biomass in AM2, but thehighest harvest index was AM3. Therefore, we can increase the yield and harvest index byincreasing grain number per spike and grain weight in proper cultivation management models.3.Effect of different cultivation management models on carbon metabolism and materialproductionThe experiment results showed that, chlorophyll content, net photosynthetic rate (Pn),transpiration rate (Tr) and stomatal conductance (Gs) in flag leaf post-anthesis was graduallyreducing with the filling progresses while the intercellular CO2concentration (Ci) wasincreasing. Compared with FM, the adjustment models have improved the photosyntheticcharacteristics of flag leaf during filling stage, which made foundation for formatting morephotosynthesis assimilation products.Soluble sugar and sucrose content in flag leaf showed a trend of single peak during thefilling period of winter wheat, and reached a peak on the20th days after anthesis. AM3wasthe highest and FM the lowest content during filling period. There was mach differenceamong models in the early filling stage, in the late filling stage was littler. Soluble sugar andsucrose content in grain gradually declined with the filling process, and AM3was the highestcontent in the grain filling stage. SS and SPS in flag leaf showed a single peak curve, and thepeak appeared at the20th day after anthesis. SS and SPS in grain gradually declined with thefilling process, and the enzyme activity of the vulnerable grain was less than the strong grain.Compared with FM, the adjustment models improved the activity of SS and SPS in flag leafand grain, and the more of improved was AM3.There were different in dry matter accumulation dynamic at different stages in differentmodels. The dry matter accumulation in FM and AM1were higher than AM2and AM3before the jointing stage in the jointing stage, and the accumulation of AM2was significantlyhigher than other models from post-jointing stage to maturity. The translocation amount ofdry matter storage in vegetative organs before anthesis showed as: stems＞sheath＞leaf＞glume, and AM2was the highest in the translocation amount and the operation rate beforeanthesis, the translocation rate was22.74%-31.63%. 4.Effect of different cultivation management models on Nitrogen assimilation of use ofwinter wheatThe experiment results showed that the NR activity in the flag leaf gradually declinedwith the filling process; NR activity of AM3was higher in the early and late grain filling, andNR activity of FM was higher than the adjustment models; GS activity in flag leaf firstlyincreased and then decreased with the filling process, and the highest activity was at the10thday after anthesis; The GS activity in grain gradually declined with the filling process, and thestrong grain had higher content than the vulnerable grain; AM2and AM3had the higherenzyme activity in filling stage, and the difference between AM2and AM3was notsignificant.The vegetative organs nitrogen storage, translocation amount and ratio of pre-anthesis inleaf were the highest, followed by the stem, sheath, glume and cob. The nitrogen translocationamount pre-anthesis take about80%on the grain contribution, FM contribution rate ofnitrogen on grain storage of post-anthesis was higher than the adjustment models. Comparedwith other models, AM3dramatically improved the contribution nitrogen on graincontribution rate post-anthesis. AM2was the highest in nitrogen accumulation amount, grainabsorption nitrogen amount and nitrogen harvest index, AM1was the highest in nitrogenpartial productivity and ratio of output to input, AM3was the highest in nitrogen useefficiency.Comprehensive comparison the effects of different cultivation management models onwheat growth and development, fertilizer and water environment, grain yield formation,carbon and nitrogen metabolism, dry matter production and nitrogen use efficiency, AM1is acultivated management model which should be popularized in current wheat production, butwith the development of wheat production, the improvement of yeild and the efficient use ofresources requirements, AM3will have a great development.