温度、水分和施氮量对温室土壤pH及电导率的耦合作用

Coupling effects of temperature,moisture,and nitrogen application on greenhouse soil pH and EC

选取5年棚龄温室土壤样品进行培养试验,研究温度(T)、水分(W)、施氮量(N)及其耦合效应对温室土壤pH及电导率(EC)的影响.结果表明:随着培养时间延长,温室土壤pH逐渐下降,下降速率可用一级反应模型进行定量描述,其速率常数受各因素的影响表现为N>W>W×N>T×W.EC在培养的第1周内快速上升到最大值后略有下降,并在培养后期逐渐趋于稳态值(ECsty),ECsty受N、W、T×W、T及W×N的影响,其中N、W、T×W和T的影响达到极显著水平,W×N的影响达到显著水平;通过减小施氮量及适当亏水灌溉可有效延缓温室土壤酸化和EC升高.建立了pH下降速率常数及ECsty回归模型,可对不同环境及水肥条件下土壤酸化及EC变化进行预测.

A laboratory incubation experiment was conducted to study the effects of temperature （T）, moisture （W）, nitrogen application （N）, and their combinations on the pH and EC of greenhouse soil having cultivated for 5 years. The results showed that with the increase of incubation time, soil pH was decreasing, which could be well described by the first-order kinetic model, and the pH decreasing rate （k） under effects of test factors was in the order of N 〉 W 〉 W 〉 N 〉 T ×W. Soil EC increased quickly to the maxima in the first week of incubation, decreased slightly then, and finally reached to a constant （ECsty）. The ECsty value was significantly affected by N, W, T × W, T, and W x N. Reducing nitrogen application and rational deficit irrigation could effectively postpone the soil acidification and EC increase. A regression equation of k and ECsty was established, which could be used to predict the changes of soil pH and EC under different conditions of moisture regime and nitrogen application.