摘要
根据８９个水稻氮磷钾田间试验结果，认为三元肥效模型是否属于典型式取决于模型极值存在与否和极值性质。依据极值判别结果，可将三元肥效模型分为典型式和三种不同类型的非典型式。分析了不同类型三无效模型的施肥意义和极值判别方法，并对非典型式提出了施肥建议。…（１）以Ｎ，Ｐ２Ｏ５，Ｋ２Ｏ分别施１５０、７５和９０ｋｇ／ｈｍ２为基准（下同），该模型的三条偏回归线则如图１所示，它们都是有极大值的抛物线。因此，可用导数法求该式的推荐施肥量。结果是最高施肥量为Ｎ１５８、Ｐ２Ｏ５５９、Ｋ２Ｏ６９ｋｇ／ｈｍ２；当每公斤Ｎ ２．６元，Ｐ２Ｏ５３．３元和Ｋ２Ｏ２．４元以及稻谷０．８元时，最佳施肥量为Ｎ １３２、Ｐ２Ｏ５５０、Ｋ２Ｏ６２ｋｇ／ｈｍ２。代入原式得最高产量为７６５０ｋｇ／ｈｍ２，最佳产量为７５４５ｋｇ／ｈｍ２。２．２．２极大值属于远外推的非典型式有些肥效模型虽有最高产量，但极值点却落在肥料试验设计量的范围外，属于外推结论，这类模型的Ｎ．Ｐ．Ｋ三条偏回归线的一次项或二次项系数间的数值大小差异悬殊，用导数法求得的施肥量必有一个或一个以上属于外推结论，因此不能用于施肥实践。福清市的一个晚稻试验结果就是这样的。该式的三条偏回归线中，Ｐ?
According to 89 trials on N,P, K in paddy field , it was suggested that the typicality of three-fertilizer efficiency model was desided by the existence and the character of extreme value.Based on the distinguished results of extreme value,three-fertilizer efficiency model may be clas-sified as typical model and three types of non-typical model,The character of different types of three-fertilizer efficiency model and the distinguish methods were analysed, and the recommenda-tory fertilization for non-typical model was contributed in this thesis.
关键词
三元肥料
肥效模型
极值判别
施肥
氮
磷
钾
Three-fertilizer efficiency model
Extreme value
Distinguish analysis
Recommenda-tory fertilization
