Responses Of Dryland Wheat Yield Formation Process To Light And Temperature Under Different Tillage Measures

The study has researched the law and the effect of temperature on different light,leaf area index and yield of wheat growth stage changes by simulating three different tillage methods using modified APSIM model parameters based on field experiment,analysed the results by using the method of multiple regression and path analysis.The main conclusions are as follows:1.The APSIM model can effectively simulate wheat’growth conditions.Acc ording to the experiment data under different tillage methods data show from 2002 to 2012 in observation station,we can get the conclusion that the simulated values and measured values fitted well of simulation area,biomass and yield o f wheat leaf under different tillage methods,the error is small,the coefficient of determination(R~2)were above 0.92.2.Growth period of wheat in Dryland has shortened with the increase of temperature.The whole growth stage(seedling and mature relationship with 4D)has shortened for 4d with temperature rise every 1℃,No change has happened in growth period of days when the temperature rise of 2℃.Solar radiation’s increasing has no obvious influence on wheat growth period.3.Under different tillage measures to increase wheat LAI light showed single peak curve similar,LAI has up to maximum until heading stages.The maximum LAI under different tillage measure were:NTS>CT>NT,namely the no-tillage leaf area index greater than conventional tillage is higher than traditional tillage systems,and in the same light conditions,compared to the other two tillage,no-tillage way had higher LAI during the whole growth period.Temperature change showed a negative effect on wheat LAI at heading stage,light is more bigger,the leaf area index increases more slowly,the largest LAI and this stage there is for light is smaller,the maximum LAI.4.Under different tillage wheat leaf area index with temperature increase showed a single peak,and under different temperature,maximum leaf area index in heading stage were:NTS>T>NT.Temperature hand leads to LAI time and reached the maximum value ahead of time,on the other hand,the peak maximum of LAI level is:temperature,maximum leaf area index increases,but when the temperature rises to a certain extent,the leaf area index has declined slightly with increasing temperature.The maximum LAI is first increased and then decreased.5.The relationships between wheat yield and the light and temperature were quadratic parabola has showed a trend of decreasing.Meanwhile,the decreasing effect of wheat yield of NTS is greater than that of T and NT.Under the condition of different cultivation measures,the light has not changed if the annual average temperature rise 1℃,the maximum material reaches as high as 16.2%,an average of7.6%,and when at constant temperature,if the average light increase 1 MJ/M~2,maximum material reaches as high as 13.8%,an average of 3.9%.In 3 tillage systems,NTS main effect is greater than that of T and NT,show that rise the same of light or temperature,the decreasing effect of wheat yield of NTS is greater than the other two kinds of farming methods.In contrast,reduce the same of light or temperature,the increasing effect of wheat yield of NTS is greater than the other two kinds of farming methods obviously.