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目前开展的施氮对土壤呼吸影响研究大多基于实验观测结果,受实验地自然条件的限制,不能研究在一定条件范围内土壤呼吸对施氮响应的连续变化。通过喷洒NH_4NO_3水溶液,设置对照(C,no N added),低氮(L,5 gNm~(-2)a~(-1)),中氮(M,15gNm~(-2)a~(-1)),高氮(H,30 gNm~(-2)a~1)4种处理水平,使用GA-BP人工神经网络建立樟树林土壤呼吸对施氮响应的模型,并将模拟结果使用响应曲面法展示,研究土壤呼吸对施氮响应的变化。研究结果表明,施氮对樟树林土壤呼吸既有抑制作用又有促进作用,其程度是由土壤温湿度条件决定的,总体上使得施氮对土壤呼吸在低土壤湿度的条件下主要表现为促进作用,在高土壤湿度条件下主要表现为抑制作用,在一部分土壤温湿度组合下表现为无明显作用。GA-BP人工神经网络模型以其特性,可以模拟土壤呼吸对施氮响应的连续变化,并在一定程度上解释了施氮量、土壤呼吸、土壤温度和土壤湿度之间复杂的数学关系。
At present, the research on the effect of nitrogen on soil respiration is mostly based on experimental observations. Due to the limited natural conditions, we can not study the continuous change of soil respiration on nitrogen application under certain conditions. By spraying NH_4NO_3 aqueous solution, we set control (C, no N added), low nitrogen (L, 5 gNm -2 a -1), medium nitrogen (M, 15 gNm -2 a - 1) and high nitrogen (Hg, 30 gNm -2 a -1) were used to establish a model of soil nitrogen respiration of camphor forest using GA-BP artificial neural network. The simulation results were analyzed using response Surface method shows the changes of soil respiration on nitrogen application. The results showed that nitrogen application could not only promote the soil respiration but also promote the soil respiration. The degree of nitrogen application was determined by the soil temperature and humidity conditions, and the overall effect of nitrogen application on soil respiration at low soil moisture was mainly promoted Effect, mainly in high soil moisture conditions for the inhibition, in a part of the soil temperature and humidity combinations showed no significant effect. The characteristics of GA-BP artificial neural network model can simulate the continuous change of soil respiration to nitrogen application, and to some extent explain the complicated mathematical relationship between nitrogen application rate, soil respiration, soil temperature and soil moisture.