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

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 x N > T x W. Soil EC increased quickly to the maxima in the first week of incubation, decreased slightly then, and finally reached to a constant (EC(sty)). The EC(sty) value was significantly affected by N, W, T x 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 EC(sty) was established, which could be used to predict the changes of soil pH and EC under different conditions of moisture regime and nitrogen application.