摘要
【目的】探究灌排调控稻田地下水补给特征及其响应机制。【方法】设置灌水下限分别为50%、60%、70%、80%饱和含水率的4种灌溉处理(分别记为I1、I2、I3、I4)和地下水埋深分别为30、50、70 cm的3种排水处理(分别记为D1、D2、D3)进行灌排组合,基于Hydrus-1D模型开展细化灌排情景下稻田土壤水分通量模拟。【结果】模型对稻田不同深度土壤含水率模拟结果的RMSE在0.0104~0.0884之间、NSE为0.0415~0.7612,稻季稻田土壤水-地下水转化量模拟值与实测值相对误差为4.6%,取得了良好的模拟精度,结合实测数据率定后的Hydrus-1D模型能够分析灌排调控稻田地下水补给特征。稻田地下水补给峰值及总量随灌水下限降低而升高,I1处理下,典型时段内稻田地下水补给峰值的平均值分别较灌水下限为I2、I3、I4稻田提高50.42%、50.42%和92.93%,而稻田地下水补给总量分别平均提高了2.15、1.78、4.82 mm。稻田地下水补给峰值及总量随地下水埋深的增加而降低,典型时段内D1处理稻田地下水补给峰值的平均值分别是D2、D3处理稻田的2.30倍、4.73倍,D3处理稻田地下水补给总量分别平均较D1、D2处理稻田降低了48.47、34.22 mm。【结论】地下水埋深、灌水下限均显著影响了稻田地下水补给总量,且地下水埋深的影响强于灌水下限。在现行的节水灌溉水分管理模式下,通过设置减小地下水埋深的排水措施,可增强农田地下水补给过程,进一步调控作物需水以提高水稻水分利用率。
【Objective】Water flow between soils and groundwater not only affects regional hydrological cycle but also groundwater use by plants.The aim of this paper is to investigate how shallow groundwater and soil water in paddy fields exchange under different combinations of irrigation and drainage.【Method】We considered four irrigation treatments by keeping the low-limit of soil saturation to resume irrigation at 50%(I1),60%(I2),70%(I3)and 80%(I4),and three drainages with the critical depths for grounder water table not to rise beyond kept at 30 cm(D1),50 cm(D2)and 70 cm(D3).Water flow in the soil under each scenario was simulated using the Hydrus-1D.【Result】T he model was able to reproduce the change in soil moisture measured in the field,with RMSE for soil water content at different depths varying from 0.0104 to 0.0884,and their associated NSE in the range of 0.0415 to 0.7612.The relative error between the simulated and measured water exchange between unsaturated soil and the groundwater was 4.6%.Water ascendence from the groundwater to the soil increased as the low-limit soil saturation set for irrigation increased and the critical groundwater depth for drainage decreased.The average groundwater discharge to soil peaked in I1,increasing by 50.42%,50.42%and 92.93%compared to that in I2,I3 and I4,respectively.The peaked and total groundwater discharge to the soil both decreased with the decrease in groundwater depth.The average discharge peaked in D1,being 2.30 times and 4.73 times that in the D2 and D3,respectively.The total groundwater discharge in D3 was 48.47 mm and 34.22 mm less than that in D1 and D2,respectively.【Conclusion】Groundwater depth and irrigation scheduling both affected the total amount of capillary rise in paddy fields at significant level,especially the groundwater depth.Dropping the groundwater depth coupled with water-saving irrigation in paddy fields could effectively enhance capillary rise and improve groundwater use efficiency of crop.
作者
杨锋
和玉璞
洪大林
纪仁婧
夏超凡
YANG Feng;HE Yupu;HONG Dalin;JI Renjing;XIA Chaofan(State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Nanjing Hydraulic Research Institute,Nanjing 210029,China;Nanjing Yangtze River Management Office,Nanjing 210011,China)
出处
《灌溉排水学报》
CSCD
北大核心
2021年第11期90-97,共8页
Journal of Irrigation and Drainage
基金
国家自然科学基金项目(51609141)
中央级公益性科研院所基本科研业务费专项资金项目(Y920009)。
