小尺度下滴灌棉田养分管理分区研究

以小尺度下滴灌棉田为研究对象,采集研究区87个耕层土壤(0～30 cm)样品,土壤有机质、全氮、速效磷和总盐含量为变量进行土壤养分精确管理分区研究。结果表明,运用模糊c-均值聚类法进行分区,并采用c-φ多次组合法来确定适宜的模糊控制参数,得出研究区最佳分区数为4,模糊指数为1.7,平均混乱度指数为0.29,土壤属性数据的模糊分类输出结果不确定性较小,地理空间上土壤的隶属关系相对明确。在研究区内,模糊分类的输出结果符合管理分区的定义,各管理分区均可以作为变量施肥的单独作业单元进行耕作管理。

Study on management zones of small-scale based on soil nutrients in drip irrigation cotton field

The objective of this research was to generate management zones of Small-scale in drip irrigation cotton field.The variables of organic matter,total N,available P and total salt data determined in 87 topsoil(0～30 cm)samples were selected as data sources.The results showed that the derivative of the objective function with respect to the fuzziness exponent,c-φ was used to determine the optimum fuzzy control parameters.The optimum number of the classes and the fuzziness exponent was 4 and 1.7,respectively.The average confusion index was 0.29 in all management zones.Thus,the overlapping of fuzzy classes at points was low and the spatial distribution of membership grades was unambiguous.In the study area,fuzzy classification of the output in line with the definition of district management,them management zones could then be used to help guide the rate of fertilizer application in an effort to manage soil nutrient levels more efficiently.