Regulative Effect Of Ecological Factors On Maize Yield Performance And Its Models Establishment

Ecological factors plays an important role in crop yield, effect of ecological factors on crop yield performance is the most important factor. Increase crop yield not only consider the cultivation, but also consider the ecological factors, light, temperature, water and other ecological factors affect grain yield through the parameters of yield performance equation. At present, the ecological factors on the parameters of yield performance equations is not reported yet, so research the quantitative relationship in the corn yield process of the formation have a great significance. The research is carried out in 2008-2010 in Langfang, using three sowing dates, three differen maize varieties and four planting densities,and record the ecological factors, analyzed the relationship between the main cultivation measures and yield performance, then established the dynamic model between accumulated temperature and dry matter accumulation, leaf area index,the results showed that.(1) Sowing date plays an main regulatory role on corn growth days,with the delayed of sowing dates, the growth days reduced. The largest accumulated temperature from emergence to maturity were normalized, the relative dynamic simulation model is developed, y=a/(1+b*e-cx),R2=0.98.Comparing equation parameters, a, c values varied smaller in sowing dates, b value varied greatly in sowing date and cultivars. The results show that sowing dates and cultivars mainly adjusted the b value in the dynamic simulation model(2) The largest LAI and accumulated temperature from emergence to maturity were normalized, and the six main models were compared. Results show that, the Ration equation y=(a+bx)/(1+cx+dx2) had a good simulation results and would be used significantly in biological applications, the equation was y=(-0.05247+1.2766x)/ (1-2.6346x+3.6359x2), r= 0.9479**, where is relative seedling groups LAI, (a+ b)/(1+c+d) is the relative maturity groups LAI. The values of a and c had a slightly difference, however, the values of b and d changed dramatically among sowing dates and among varieties, and a small difference among densities, showing that sowing dates changed the LAI mainly through the values of b and d in maize. The accuracy and precision of the normalized model were tested with the data of 2008 and the data of 2007 in Huadian, Jilin, the simulation accuracy (k) was all above 0.9392**, and the precision (R2) was all above 0.9996**. Sowing dates regulated the growth days, average temperature, accumulated temperature, average LAI, change rate of LAI and grain yield in different maturity cultivars of maize, when the sowing date delayed, the growth days, accumulated temperature, the average LAI and grain yield were all decreased, the average temperature was increased. The growing days and accumulated temperature showed as Denghai 661> Xianyu 335> Yinong 103, grain yield and average LAI showed as Xianyu 335> Denghai 661> Yinong 103.(3) The dry matter accumulation dynamics and grain yield were measured. A richard curve equation, y= 1.1044/(1+e2.0253-5.1927x)1/0.4448, was developed with normalized DMA and normalized accumulated temperature. Ultimate growth the basic parameter (a) was 1, initial growth parameters (b) and growth rate parameters (c) values changed dramatically, shape parameter (d) changed small. The accuracy and precision of the normalized model were tested with the data of 2008 and the data of 2007 in Huadian,Jilin,the dynamic model could make a good estimation of DMA dynamics with the accuracies were all above 1.0486**,and the precision (R2) were all above 0.9534**.According to accumulated temperature and the largest dry matter accumulation,use the model can better restore the dry matter accumulation dynamic of the growth period. Sowing-date and density have a regulated role in the change rate of dry matter accumulation.The sixth leaf and waxy stage were the sensitive reaction period of dry matter accumulation rate in density. In the slow increase and down stage of the dry matter accumulation rate, the accumulated temperature for maize increased gradually,In the rapid increase stage, the accumulated temperature for maize decreased gradually. In the growing period, the average rate of dry matter accumulation of different cultivars shown as, Xianyu 335> Denghai 661>Yinong 103,The average rate of dry matter accumulation of different sowing date shown as,Early Sowing> Middle Sowing>Late Sowing,The average rate of dry matter accumulation increased with the density increasing. (4) With planting date delayed,grain yield,growth days, average leaf area index, harvest index and grains per spike were decreased; The average net assimilation rate was followed an increasing trend, but no significant difference between ears. Grain yield, average leaf area index and ears were followed by an increasing trend respectively with the density increasing, average net assimilation rate, growth period of days, harvest index and grains per spike were followed by decreasing trend with the density.The seven indexes of yield performance had a positive effects on yield, average leaf area index had a indirect effect on yield through growing days and, ears, ears had a lager positive effect. Average leaf area index through the average net assimilation rate, panicle,1000-grain weight, and the average net assimilation rate, had a lager negative effects on yield. Balanced the relationship between yield performance indexes and yield, increase early-sowing and increase density properly could increase the leaf area index, growth period of days and spikelets.(5) Ecological factors have an effect on yield and yield performance index, effective temperature after silking affect average leaf area index and mean net assimilation rate, the daily average temperature affect the growth days and harvest index,the total rainfall and sunshine hours affect grains number per spike and grain weight. Whole growth period, especially after silking effective temperature effective temperature is the most important ecological factors affecting grain yield.Grain yield response to effective temperature of the whole growth period, average daily temperature, effective accumulated after silking, rainfall, sunshine hours, average daily temperature consistent with quadratic relations, y= ax2+bx+c, and has a good correlation,with the ecological factors increase, then the yield gradually increased, reached the highest value, yield gradually decreased.