土石山区小流域土壤磷素的空间分布特征与有效性

以汉江余姐河小流域为研究区域,运用经典统计学与地统计学方法,分析流域不同土地利用类型下表层(0~20 cm)土壤全磷和速效磷的空间分布特征及磷素有效性.结果表明:流域农地、林地和草地土壤全磷含量平均值分别为0.368 g·kg~(-1)、0.347 g·kg~(-1)和0.348 g·kg~(-1),土壤速效磷含量均值分别为17.52 mg·kg~(-1)、19.23 mg·kg~(-1)和17.90 mg·kg~(-1).土壤全磷和速效磷空间分布的最优模型均为高斯模型且均具有中等空间相关性.克里格插值表明研究区土壤全磷呈斑块状分布,速效磷含量的高值区沿河流呈网状分布,尤其是速效磷含量为10~20 mg·kg~(-1)和20~30 mg·kg~(-1)的区域从流域上游至下游以河流为主线依次连通.经ANOVA检验,土地利用类型对土壤全磷和速效磷的空间分布影响不显著(p0.05),不同土地利用下每平方米土壤全磷含量表现为草地农地林地,分别为0.092 kg·m~(-2)、0.089 kg·m~(-2)和0.087 kg·m~(-2),速效磷含量表现为草地林地农地,分别为4.67 g·m~(-2)、4.11 g·m~(-2)和3.89 g·m~(-2),流域土壤磷素的有效性呈现出林地草地农地的特征.

Spatial distribution and effectiveness of soil phosphorus in the mountain Watershed

The spatial variability soil total phosphorus (STP) and Olsen-phosphorus (Oslen-P) content in a small mountain catchment of the Han River were analyzed using classical statistics and geo-statistical analysis. The results showed that the mean STP content of cropland, forestland and grassland at a depth of 0~20 cm was 0.368, 0.347 and 0.348 g·kg^-1, respectively. The mean Oslen-P content of cropland, forestland and grassland at a depth of 0~20 cm was 17.52, 19.23 and 17.90 mg·kg^-1, respectively. Gauss model was the optimal model of the spatial distribution of STP and Oslen-P content with a moderate spatial correlation. Classical Kriging could successfully interpolate STP and Oslen-P content in the catchment. The distribution of STP content was patchy distribution. High value area of Oslen-P content was like a network distribution along the river. In particular, the area of Oslen-P content 10~20 and 20~30 mg·kg^-1 is connected with river from the upstream to the downstream in the catchment. ANOVA indicated that the spatial variation of STP and Oslen-P content under different land use types was not significant (p<0.05). STP density of cropland, forestland and grassland at a depth of 0~20 cm was 0.092, 0.089 and 0.087 kg·m^-2, respectively. In comparison, Oslen-P density of cropland, forestland and grassland was 4.67, 4.11 and 3.89 g·m^-2, respectively. The effectiveness of soil phosphorus in Yujiehe watershed of different land-use types followed the order woodland > grassland > farmland.