Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impac...Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 000 000 digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.展开更多
景观异质与土壤分异息息相关。以DEM数据为基础,以海拔50m、100m为界,将江汉平原划分为平原湖区景观、平缓岗地景观及起伏丘陵景观3种类型。在ArcG IS 10支持下,将江汉平原土壤图与景观类型图进行叠置分析,提取不同景观类型片区各土壤...景观异质与土壤分异息息相关。以DEM数据为基础,以海拔50m、100m为界,将江汉平原划分为平原湖区景观、平缓岗地景观及起伏丘陵景观3种类型。在ArcG IS 10支持下,将江汉平原土壤图与景观类型图进行叠置分析,提取不同景观类型片区各土壤亚类斑块周长、面积等信息,计算了各景观类型片区各土壤亚类的分维数、平均斑块面积、稳定度等信息,定量分析了江汉平原各景观类型片区土壤空间分异特征,结论如下:(1)不同景观类型区各土壤亚类分布差异明显,起伏丘陵景观区主要以红壤和黄棕壤地带性土壤为主;平原湖区潮土和水稻土等耕作土非常发育;平缓岗地区地带性土壤和耕作土壤平分秋色。(2)连片性较好的土壤亚类呈现不同的景观选择性:耕作土集中分布于平原湖区景观片区;地带性土壤多集中分布于丘陵和岗地景观片区。(3)平原湖区面积很大,各类土壤都有发育的空间,土壤亚类之间分维数和稳定度差别比较大;平缓岗地景观区由于面积非常局限,土壤亚类发生发育受到空间的限制,边界破碎化,分维数平均都比较大,斑块镶嵌结构均比较复杂,稳定度差别较小。(4)主要土壤亚类的分维数和稳定性指数值一定程度地反映了各主要土壤亚类的最匹配的景观类型,即能够提供其发生发育的最佳条件。研究有利于深入认识土壤形成和演化规律,为土壤资源的合理利用及定向培育服务。展开更多
基金Project supported by the National Key Basic Research Program (973 Program) of China (No. 2007CB407206)the National Natural Science Foundation of China (No. 40621001)the Frontier Project of the Chinese Academy of Sciences (No. ISSASIP0715)
文摘Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 000 000 digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.
文摘景观异质与土壤分异息息相关。以DEM数据为基础,以海拔50m、100m为界,将江汉平原划分为平原湖区景观、平缓岗地景观及起伏丘陵景观3种类型。在ArcG IS 10支持下,将江汉平原土壤图与景观类型图进行叠置分析,提取不同景观类型片区各土壤亚类斑块周长、面积等信息,计算了各景观类型片区各土壤亚类的分维数、平均斑块面积、稳定度等信息,定量分析了江汉平原各景观类型片区土壤空间分异特征,结论如下:(1)不同景观类型区各土壤亚类分布差异明显,起伏丘陵景观区主要以红壤和黄棕壤地带性土壤为主;平原湖区潮土和水稻土等耕作土非常发育;平缓岗地区地带性土壤和耕作土壤平分秋色。(2)连片性较好的土壤亚类呈现不同的景观选择性:耕作土集中分布于平原湖区景观片区;地带性土壤多集中分布于丘陵和岗地景观片区。(3)平原湖区面积很大,各类土壤都有发育的空间,土壤亚类之间分维数和稳定度差别比较大;平缓岗地景观区由于面积非常局限,土壤亚类发生发育受到空间的限制,边界破碎化,分维数平均都比较大,斑块镶嵌结构均比较复杂,稳定度差别较小。(4)主要土壤亚类的分维数和稳定性指数值一定程度地反映了各主要土壤亚类的最匹配的景观类型,即能够提供其发生发育的最佳条件。研究有利于深入认识土壤形成和演化规律,为土壤资源的合理利用及定向培育服务。
