Effect Of Chemical Control Technology On Crop Evapotranspiration And Water Productivity Of Four Legumes In Two Accumulated Temperature Zone

The planting area of legumes in recent years is increased with the adjustment of planting structure in Heilongjiang Province.However,the fluctuation of precipitation and increase of heat stress in the crop growth season,which affect the crop water requirement and decrease indeed the crop yield.Crop evapotranspiration is an important parameter to estimate crop water requirement.The P-M model,as a classical approach to estimate crop evapotranspiration,was run by specific crop efficient(Kc).But it is actually dynamic for Kc which determined by surface resistance(rs),aerodynamic resistance(ra)and vapor pressure deficit(VPD).However,the Matt-shuttleworth in recent years propose M-S model which use actual rs,ra and VPD of field crop to estimate crop water requirement.Therefore,M-S model in this research was run to estimate daily actual evapotranspiration of soybean,mungbean,kidneybean and adzukibean,and spraying plant growth regulator including S-3307 and DTA-6 on flowering period of crop for improving crop water use efficiency.The field experiment was conducted in Jiusan and Lindian sites from 2015 to 2017 year.The result indicated in the following:1.The accumulated evapotranspiration of soybean in the full growth period was highest(227.01mm),the accumulated evapotranspiration of adzukibean was lowest(183.42mm).In the vegetative growth stage,the accumulation evapotranspiration of mungbean was highest and while the accumulated evapotranspiration of soybean was lowest(77.21mm).In the reproductive stage,the accumulated evapotranspiration of soybean was highest.The daily actual evapotranspiration of adzukibean in the seedling period was lowest(1mm/day),the continue days of the highest daily evapotranspiration for kidneybean was longest,the speed decreased of daily actual evapotranspiration for adzukibean was fastest.2.The Gaussian distribution model based on crop morphological parameters including crop height(HC)and leaf area index(LAI)was built.The expected value of leaf area index in the model was higher compared with expected value of crop height,which indicted the weight of LAI was higher in the process of calculating crop dailyactual evapotranspiration.Besides,the anti-proportional relationship between the crop height and daily actual evapotranspiration was obtained.Moreover,the root mean square error(RMSE)of model was low(from 0.5~0.8)and the P-mean was less than0.0001.3.The biomass water productivity of mungbean in the maturity period was highest(mean 35.72Kg/hm2/mm),the yield water productivity of soybean was highest(mean 11.33Kg/hm2/mm).However,the biomass and yield water productivity of adzukibean were lowest(27.17Kg/hm2/mm and 8.99Kg/hm2/mm).The crop yield and biomass water productivity by spraying S-3307 and DTA-6 were increased compared with CK treatment.The yield water productivity of four crops by spraying S-3307 were highest.The above result about character of crop water requirement in different growth period can be used in field actual water management.Besides,the water use efficiency by spraying S-3307 was increased and obtain high crop water productivity.