建三江主要作物需水量变化趋势与关键影响因子识别

Change Trend and Key Influencing Factors Identification of Main Crops Water Demand in Jiansanjiang

基于建三江垦区1995—2018年逐日气象数据,采用PenmanMonteith公式结合单作物系数法计算其主要作物水稻、玉米、大豆生育期的需水量,利用去趋势预置白(TFPW)的MannKendall(TFPWMK)研究3种作物需水量变化特征,并通过重标极差(R/S)分析法预测作物未来需水量变化趋势;借助通径分析法研究6个气象因子与作物需水量的相关性,识别了作物需水量变化的关键影响因子,并分析了关键影响因子变化与作物需水量变化趋势间的关系。结果表明:建三江垦区主要作物水稻、玉米、大豆全生育期需水量存在显著差异,3种作物多年平均需水量分别为484.84、425.91、319.11 mm;影响水稻、玉米和大豆需水量的关键影响因子为平均气温、净辐射和日照时长,对作物需水量有明显增进作用;风速、相对湿度通过与其他因子协同作用对作物需水量有一定限制作用;在1995—2018年时间序列中,水稻和大豆的全生育期作物需水量呈上升趋势,玉米的全生育期需水量呈下降趋势;未来,水稻和大豆全生育期需水量呈上升趋势,玉米全生育期需水量呈降低趋势。研究可为该垦区作物灌溉水量分配和灌溉制度的制定提供决策依据。

Studying the trend of crop water demand and identifying key influencing factors can provide a basis for scientific crop irrigation,improvement of agricultural water use efficiency,and optimal allocation of water resources.Based on the daily meteorological data of Jiansanjiang Reclamation Area from 1995 to 2018,according to the PenmanMonteith formula combined with the single-crop coefficient method,the water requirement of the main crops of rice,corn,and soybeans during the growth period were calculated.Using the trend-free pre-whitening MannKendall(TFPWMK)method to study the change characteristics of the water demand of three crops,adopt the rescaled range(R/S)analysis method to predict the change trend of the future water demand of the crops,and the path analysis method was used to quantitatively analyze the influence of six meteorological factors such as average temperature,net radiation,sunshine hours,wind speed,precipitation,and relative humidity on crop water demand.The key influencing factors of water demand changes were determined,and the relationship between the change trend of key influencing factors and the change trend of water demand was analyzed.The results showed that the average multi-year water requirement of the reference crops in Jiansanjiang Reclamation Area was 606.68 mm.The inter-annual changes in the water requirement of major crops such as rice,corn and soybeans during the growth period were relatively stable.There was a significant difference between the amount of water.The average multi-year water requirement of the three crops were 484.84 mm,425.91 mm and 319.11 mm,respectively.In the time series from 1995 to 2018,the water demand of rice and soybeans during the whole growth period showed an upward trend,while the water demand of maize during the whole growth period showed a downward trend.In the future,water demand during the whole growth period of rice and soybeans would increase,and water demand during the whole growth period of corn would decrease.Average temperature,radiation and sunshine hours were the key influencing factors for the water demand of rice,corn and soybeans,and they played a role in increasing the water demand.Precipitation increased the water demand of crops,but it was not obvious.Wind speed and relative humidity played a certain restrictive effect on the water demand of the three crops.Therefore,the water demand of rice,corn and soybeans in Jiansanjiang Reclamation Area was affected by many influencing factors.The change trend of water demand caused by the changes of meteorological factors during the whole growth period of rice and soybean was consistent with the change trend of water demand of rice and soybean in the TFPWMK test analysis.The increase in the average temperature during the whole growth period of corn was not enough to offset the influence of radiation and the reduction of sunshine hours on the water requirement of corn,so the water requirement of corn showed a downward trend,which was consistent with the change trend of water requirement of corn in the TFPWMK test analysis.