上海市奉贤区土壤墒情变化规律与评价指标研究

Changing law and evaluation index system of soil moisture in Fengxian District of Shanghai

土壤水分动态变化研究在农业生产中具有重要意义,是作物科学灌排的基础。运用上海市奉贤区2014—2018年的气象资料及定点墒情监测数据,分析奉贤区土壤墒情的季节变化规律和演变特点,建立以水量平衡法为基础原理的时段墒情诊断模型进行预报,并利用自动监测仪的特性,形成小青菜墒情评价指标体系。结果表明:奉贤区表层土壤墒情受降雨和气温影响较大,总体经历缓慢变化期(2—5月)、剧烈变化期(6—9月)和逐步稳定期(10月—次年1月)3个阶段,其中土壤墒情最低值出现在7—8月。平衡法时段墒情诊断模型能较好地预报土壤含水量,决定系数为0.9214,经预测值与实测值误差验证后,可用于预报作业。通过对土壤墒情实时变化监测分析,初步掌握夏季小青菜生长阶段对土壤含水量的需求,并建立相应的墒情评价指标体系。盆栽试验表明,该指标体系科学合理,可作为奉贤区夏季青菜的土壤含水量监测的定量评估标准和农田水分精准管理的依据。

Dynamic changes of soil moisture had important significance in agricultural production and scientific irrigation and drainage of crops.Based on meteorological data in Fengxian District during 2014—2018,the seasonal changing law of soil moisture and its characteristics were analyzed,and the balance diagnostic model of soil moisture in different periods was established.A soil moisture evaluation index system of green vegetables in summer was formed,which used the superiorities of automatic monitor.The results showed that the precipitation and temperature had a great impact on the superficial soil moisture.There were three main stages of soil moisture in a year:slow change period(form February to May),dramatic change period(form June to September)and gradual stabilization period(form October to January next year).However,the lowest value of soil moisture appeared in July or August.The forecasting model simulated the dynamic change of soil moisture very well,decision factor was 0.9214.Therefore,it could be used for predict the soil moisture after verification of predictive value and actual value.The suitable soil moisture of green vegetables in different growth period was analyzed,accordingly established the soil moisture evaluation index system of green vegetables in Fengxian District.The pot experiment showed that the index system was scientific and reasonable,which could be a quantitative evaluation standard of farmland soil moisture monitoring and precision irrigation technology.