Effects of moisture, temperature and nitrogen supply rate on NO^-₃-N accumulation in greenhouse soil

In order to ascertain that the soil water, fertilizer and temperature management affect on the NO^-₃-N accumulation of soil in greenhouse crop production, an incubation experiment was conducted to determin the changes of NO^-₃-N accumulation with time during the process of nitrification under various soil moisture(W), soil temperature(T) and nitrogen supply rate(N₀) for 5 years greenhouse soil. The results indicated that equation Δ(NO^-₃)=e^(a+b/τ) could be used to express the NO₃-N accumulation with time. The maximal rate of nitrification, delay period and maximal NO^-₃-N mass of accumulation were derived from the equation, and used to characterize quantitatively the nitrification process in different soil conditions. The effect on maximal rate of nitrification Kmax was a descending order of soil moisture, soil temperature, interaction of temperature and moisture, interaction of moisture and nitrogen supply rate, and nitrogen supply rate, and the effect on delay period was a descending order of soil moisture, soil temperature, nitrogen supply rate and interaction of moisture and nitrogen supply rate. Maximal NO^-₃-N mass of accumulation depended on nitrogen supply rate, moisture and temperature, and did not affect significantly by their interactions. In greenhouse production systems, where moisture and temperature can be controlled, this model can be used to predict NO₃-N accumulation and the effectiveness of N in the fertilizer management that considers both nitrogen supply rate and soil environment.