State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2018 Apr 15;621:177-185. doi: 10.1016/j.scitotenv.2017.11.222. Epub 2017 Nov 24.
Soil salinity accumulation is strong in arid areas and it has become a serious environmental problem. Knowledge of the process and spatial changes of accumulated salinity in soil can provide an insight into the spatial patterns of soil salinity accumulation. This is especially useful for estimating the spatial transport of soil salinity at the watershed scale. This study aimed to identify spatial patterns of salt accumulation in the top 20cm soils in a typical inland watershed, the Sangong River watershed in arid northwest China, using geostatistics, spatial analysis technology and the Lorenz curve. The results showed that: (1) soil salt content had great spatial variability (coefficient variation >1.0) in both in 1982 and 2015, and about 56% of the studied area experienced transition the degree of soil salt content from one class to another during 1982-2015. (2) Lorenz curves describing the proportions of soil salinity accumulation (SSA) identified that the boundary between soil salinity migration and accumulation regions was 24.3m lower in 2015 than in 1982, suggesting a spatio-temporal inequality in loading of the soil salinity transport region, indicating significant migration of soil salinity from the upstream to the downstream watershed. (3) Regardless of migration or accumulation region, the mean value of SSA per unit area was 0.17kg/m higher in 2015 than 1982 (p<0.01) and the increasing SSA per unit area in irrigated land significantly increased by 0.19kg/m compared with the migration region. Dramatic accumulation of soil salinity in all land use types was clearly increased by 0.29kg/m in this agricultural watershed during the studied period in the arid northwest of China. This study demonstrates the spatial patterns of soil salinity accumulation, which is particularly useful for estimating the spatial transport of soil salinity at the watershed scale.
土壤盐渍化在干旱地区较为严重，已成为严重的环境问题。了解土壤中盐分的积累过程和空间变化，可以深入了解土壤盐分积累的空间格局。这对于估计流域尺度上土壤盐分的空间输移特别有用。本研究旨在利用地统计学、空间分析技术和洛伦兹曲线，识别中国干旱西北内陆流域——三工河流域表层 20cm 土壤中盐分的空间分布格局。结果表明：（1）1982 年和 2015 年土壤盐分含量均具有较大的空间变异性（变异系数>1.0），约 56%的研究区在 1982-2015 年间经历了土壤盐分含量从一个等级向另一个等级的转变。（2）描述土壤盐分积累（SSA）比例的洛伦兹曲线表明，2015 年土壤盐分迁移和积累区的边界比 1982 年低 24.3m，表明土壤盐分传输区的负荷存在时空不平等，表明土壤盐分从上游到下游流域的迁移显著。（3）无论在迁移区还是积累区，2015 年单位面积的 SSA 均值比 1982 年高 0.17kg/m（p<0.01），灌溉地单位面积的 SSA 增加量比迁移区高 0.19kg/m。在中国干旱西北的这个农业流域，在研究期间，所有土地利用类型的土壤盐分积累明显增加了 0.29kg/m。本研究表明，土壤盐分积累的空间格局对估计流域尺度上土壤盐分的空间输移特别有用。
