title: [Spatial variability and management zone of soil major nutrients in tobacco fields in Qiannan mountainous region].
abstract: Spatial variability and management zone of soil major nutrients in tobacco fields in Qian-nan mountainous region were analyzed using geostatistics and fuzzy c-mean algorithm. Results indicated that the level of soil organic matter (OM) was moderate, and alkalytic nitrogen (AN), available phosphorus (AP) and available potassium (AK) were rich according to tobacco soil nutrient classification standards. Coefficients of variation (CV) of OM, AN, AP and AK were moderate. Contents of OM, AN, AP and AK fitted log-normal distributions. Correlation analysis showed moderate correlations between OM and AN, AP and AK. OM and AN were best described by Gaussian semivariogram models, while AP and AK were described by exponential models. The four nutrients displayed moderate spatial autocorrelation. There were significant differences among lag distances of four soil nutrients. OM, AN, AP and AK in the majority of studied regions varied at moderate to very rich levels, and deficiencies of OM, AN, AP and AK only accounted for 0.93%, 0.53%, 0.24% and 7.91% of the total studied region, respectively. Based on the results, the studied region was divided into two management zones (MZ), namely MZ1 and MZ2, accounting for 69. 8% and 30. 2% of the studied region respectively. The soil levels of OM, AN, AP and AK in MZ1 were significantly lower than those in MZ2 (P < 0.01).
authors.forename: De-Chuan
authors.initials: DC
authors.lastname: Wu
authors.forename: Hong-Xiang
authors.initials: HX
authors.lastname: Luo
authors.forename: Ze-Min
authors.initials: ZM
authors.lastname: Song
authors.forename: Guang-Dong
authors.initials: GD
authors.lastname: Guo
authors.forename: Yong-An
authors.initials: YA
authors.lastname: Chen
authors.forename: Yu-Xiang
authors.initials: YX
authors.lastname: Li
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Jiang
authors.forename: Zhang-Hai
authors.initials: ZH
authors.lastname: Li
mesh_terms: D000383:Agriculture; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D062206:Spatial Analysis; D014026:Nicotiana
chemical_list: D012987:Soil; D010758:Phosphorus; D009584:Nitrogen; D011188:Potassium