西南季节性干旱区农田土壤水分对降雨的动态响应  

Impact of precipitation on soil moisture in seasonal drought regions in Southwest China

作　　者：张曼雪 罗厚攀 陈川 余康宁 陈太阳 黄蓉 刘战东[2] ZHANG Manxue;LUO Houpan;CHEN Chuan;YU Kangning;CHEN Taiyang;HUANG Rong;LIU Zhandong(Sichuan Dujiangyan Water Conservancy Development Center,Dujiangyan 611800,China;Institute of Farmland Irrigation,Chinese Academy of Agricultural Sciences,Xinxiang 453002,China)

机构地区：[1]四川省都江堰水利发展中心,四川都江堰611800 [2]中国农业科学院农田灌溉研究所,河南新乡453002

出　　处：《灌溉排水学报》2024年第7期85-92,共8页Journal of Irrigation and Drainage

基　　金：国家现代农业产业技术体系专项(CARS-02-18)。

摘　　要：【目的】探明西南季节性干旱区不同作物下农田土壤含水率对不同降雨事件的动态响应。【方法】基于田间原位观测,结合2023年4—10月降水和土壤含水率原位连续监测数据,对比分析水稻田和玉米地土壤含水率对不同强度降雨的响应规律。【结果】①不同强度降雨对农田土壤水分补给深度影响不同,小降雨事件(降雨强度<2mm/h)对土壤补给深度为0~20cm,强降雨事件(降雨强度>8mm/h)对土壤补给深度为0~50cm;②不同作物下农田土壤水分对降雨事件的响应存在显著差异,研究期间水稻田和玉米地的土壤水分补给速率均值分别为0.72、1.07%/h,有效补给滞后时间均值分别为0.88、5.38 h,消退速率均值分别为0.04、0.02%/h;③与玉米地相比,水稻对降雨响应更敏感且响应效应更强烈,这可能与作物的冠状叶片截留、根系保水能力有关,同时土壤初始含水率影响土壤水分对降雨事件的响应效应。【结论】强降雨事件能够有效补给农田土壤水分,雨强较小或无降雨时,应根据土壤墒情及时补充地面灌溉。【Objective】Soil water is not only a resource to plants but also controls microbial activity and biogeochemical processes which are essential for ecosystem functions.Its spatiotemporal dynamics is controlled by a multitude of biotic and abiotic processes.In this paper,we investigate the response of soil water dynamics to rainfall events in the seasonal drought regions in Southwest China.【Method】The study was based on in-situ observations and rainfalls and soil watercontent measured from April to October 2023 across the region.Using these data,we analyzed the response of soil watercontent in paddy and corn fields to rainfall events with different intensities.【Result】①Rainfall intensities affected penetration depths of the rainfall water.Rainfall events less than 2 mm/h affected the soil water mainly in the 0-20 cm soil layer,whilerainfall events with intensity greater than 2 mm/h but less than 8 mm/h affected soil water in the 0-50 cm soil layer.②The responses of soil water to rainfall events varied with crops.For the corn and paddy fields,the mean effective recharge efficiency were 0.72%/h and 1.07%/h,the mean effective recharge lag time were 0.88 h and 5.38 h,and the mean regression rates were 0.04%/h and 0.02%/h,respectively,during the experimental period.③Compared withthe corn fields,the paddy fields were more sensitive to rainfall,probably due to the difference in canopy interception of the crown leaves and water uptake of the rootsbetween the two crops.The initial soil water content also affected the response of soil water to rainfall events.【Conclusion】Heavy rainfall events can effectively recharge soil water.Irrigation is needed for both crops during dry periods or periods in which rainfalls were less than 2 mm/h.

关 键 词：土壤水分 降雨 西南季节性干旱区 农田 作物 

分 类 号：S715.3[农业科学—林学]