黄骅市土壤保持价值年内动态特征

Intra-annual dynamics of soil conservation features in Huanghua City

掌握不同生态系统类型土壤侵蚀和土壤保持量的年内动态变化,对于区域水土保持重点及时序安排具有积极的指导作用。本研究在GIS支持下,运用通用土壤流失方程(USLE)对河北省黄骅市不同生态系统年内土壤侵蚀与保持量进行计算,并利用市场价值法、机会成本法对各生态系统类型年内各月的土壤保持价值进行测算,研究黄骅市土壤保持价值年内动态特征。研究表明,黄骅市全年各月土壤保持价值分配不均,年内动态特征与土壤保持量的季节动态变化规律一致,8月达到最大峰值,1—3月、10月、12月价值均为零,5—8月呈增加趋势,5—9月土壤保持价值占全年土壤保持价值的82.47%。从各生态系统类型来看,草地8月的单位面积土壤保持价值最大,为128.87元·hm?2;水域9月的单位价值最小,为11.23元·hm?2。从土壤保持价值构成来看,年内各土壤保持功能单位面积贡献价值大小排序为:减少土壤养肥流失价值>减少淤泥淤积价值>减少废弃土地价值。研究区各生态系统类型的土壤保持价值具有明显随季节变化的规律,在雨季受暴雨等短期大量降水的影响,土壤潜在的侵蚀量增大,而生态系统的土壤保持功能和价值在此过程得以发挥作用。

China is one of the countries in the world with the most severe soil erosion. Mastering various changes in regional soil erosion, soil conservation and ecological dynamics is critical for prioritization of regional soil and water conservation in time and space to combat soil erosion for sustainable development. At present, research on long-term soil conservation has ignored the erosion force of rainfall and the dynamic changes in vegetation coverage. Using GIS and Universal Soil Loss Equation（USLE）, we calculated soil erosion and soil conservation amounts in a typical coastal saline soil region, Huanghua City of Hebei Province.Furthermore, using market value and soil opportunity cost, we calculated monthly soil conservation value in the study area. The dynamic characteristics of soil conservation in coastal land ecosystems were important for ecological security and the maintenance of China’s coastal areas. The results showed uneven monthly distribution of soil conservation values that was in agreement with the seasonal dynamics of soil conservation amount which peaked in August. The soil conservation value was zero for January, February,March, October, and December, while it increased from May to August. Soil conservation value from May to September accounted for 82.47% of the total of the year. Among different ecosystems, grassland showed the highest soil conservation value per unit area inAugust（128.87 Yuan·hm-2）. The soil conservation value per unit area of water body was minimum in September（11.23 Yuan·hm-2）.For different functions of soil conservation, the order of value contributions to soil conservation value per unit area was value of reducing soil fertility loss 〉 value of reducing silt deposition 〉 value of reducing land abandonment. The soil conservation values of different ecosystems in the study area changed obviously with season. In the rainy season, the heavy short-durational rains increased soil loss, when the soil conservation functions of ecosystems were more important for combating soil loss.