基于水文气象多因子的夏玉米生育期土壤水分预测研究

Soil Moisture Prediction of Summer Maize Growth Period Based on Multi Hydrometeorology Factors

准确掌握土壤水分动态变化,对制定灌溉计划至关重要。采用五道沟实验站1991-2018年大田土壤水、地下水埋深、降雨量、水面蒸发、风速、日照时数、气温和绝对湿度7个水文气象因子,经相关分析,筛选出4个关键水文气象影响因子,以影响程度最大的为初始变量,逐个添加到4个因子,分别建立了夏玉米各生育期不同土层(0~0.2、0.2~0.4、0.4~0.6、0.6~0.8、0.8~1.0、0~0.5 m)土壤含水率多元线性回归模型。结果表明:不同土层土壤水分与气象因子均表现出一致性的相关性,其中土壤水分与地下水埋深及绝对湿度的相关性最大;开花-成熟期土壤水分与气温和绝对湿度的相关性最大;其他生长阶段与地下水埋深和绝对湿度相关性最大。随着关键影响因子的增多,其预测精度提高,当影响因子为4个时,R2最大为0.99。不同土层的土壤水分模型均具有较好的预测能力,随着土层深度的增加,平均相对误差均可控制在0.1以内。该研究对及时掌握作物各生长阶段土壤水变化,指导作物科学灌溉具有重要意义。

It is very important to accurately grasp the dynamic change of soil moisture for making irrigation plan.Seven factors of hydrometeorology including soil water,groundwater depth,rainfall,water surface evaporation,wind speed,sunshine hours,temperature and absolute humidity were used in Wudaogou experimental station from 1991 to 2018.Through correlation analysis,four key factors of hydrometeorology were selected.Taking the most influential as the initial variables and adding them to four factors one by one,the multiple regression prediction models of soil moisture content in different growth stages and different soil layers(0~0.2,0.2~0.4,0.4~0.6,0.6~0.8,0.8~1.0,0~0.5 m)of summer maize were established.The results showed that the correlation between soil moisture and meteorological factors in different soil layers was consistent;the correlation between soil moisture with groundwater depth and absolute humidity was the largest;the correlation between soil moisture with air temperature and absolute humidity was the most significant in flowering maturity period;in other growth stages,the correlation between soil moisture with groundwater depth and absolute humidity was the largest;with the increase of key influencing factors,the prediction accuracy was improved;when the influencing factors were 4,R2 was 0.99 at most;the soil moisture models of different soil layers had better prediction ability;with the increase of depth,the average relative error could be controlled within 0.1.This study is of great significance to grasp the changes of soil water in each growth stage of crops and guide the precise irrigation of crops.