摘要：
利用2008—2009年重庆市玉米测土配方施肥田间试验结果,结合重庆玉米生长期(3~8月)的气象资料,以及试验点地形条件,采用K-means和CART模型,研究了氮、磷、钾缺施条件下(Nn、Np、Nk)山地玉米产量对生态因子的响应.结果表明,氮、磷、钾不同缺施条件下玉米产量存在显著差异,缺钾、缺磷条件下玉米产量明显高于缺氮条件.氮、磷、钾不同缺施条件下生态因子对玉米产量的影响也存在很大区别:缺氮时,生态因子的相对重要性为土壤>气候>地形,土壤碱解氮含量成为影响玉米产量的重要因子;缺磷时,气候的重要性高于土壤和地形,日照是相对重要的因子;缺钾时,气候因子也占据了主导地位,降雨发挥了至关重要的作用.CART模型解释了氮、磷、钾缺施条件下玉米产量总变异的65.7%、79.8%和83.8%.%Based on the records of Soil Test & Formulated Fertilization Project implemented during 2008 to 2009 in Chongqing,combining climatic data during the maize growth period and terrain variables,the response of maize yields variability under three scenarios including the deficiency of soil nitrogen,phosphorus and potassium to ecological factors were analyzed using K-means and Classification tree model. The results showed significant differences were found among three different scenarios. Particularly,the yield with N-deficiency was lower than that with P and K-deficiency. In addition,the obvious differences among the relative importance of ecological factors to maize yields were also observed. For N-deficiency scenario,the relative importance of ecological factors were ranked by soil properties > climate > terrain,soil available nitrogen played the most important role. For P-deficiency scenario,climate variables followed by soil properties and terrain were the most important factors affecting maize yield,the sunshine hours was the most important factors. For K-deficiency scenario,climate factors also played the most important roles,rainfall was of great importance for maize yield variability. Meanwhile,the CART model explained 65.7%,79.8% and 83.8% of maize yields variability under three different scenarios.
