Ros M, Hernandez M T, García C
Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafologia y Biologia Aplicada del Segura, CEBAS-CSIC, P.O. Box 4195, 30080 Murcia, Spain.
Environ Manage. 2003 Jun;31(6):741-7. doi: 10.1007/s00267-002-2839-8.
Soils in the Mediterranean area are very prone to erosion due to the loss of organic matter and the consequent lack of protective vegetation. In this experiment a Mediterranean degraded soil with a 15% slope was amended at a rate of 250 t ha(-1) wet weight with sewage sludge and with a mixture of sewage sludge and barley straw (70% carbon from sewage sludge and 30% from the straw) in order to study their influence on soil structure recovery and hence the soils's resistance to erosion processes. Both types of organic amendment led to an improvement in several soil properties (physical, biological, and microbiological) as a result of the spontaneous growth plant covering that became evident three months after amendment. This vegetation remained throughout the two years of the experiment and prevented the water erosion processes that normally precede soil degradation. Amendment by sewage sludge alone reduced soil loss by 80% compared with the control soil, while the mixture that included both sewage sludge and barley straw reduced losses by 84%, both reducing runoff by 57%. The amended soils showed increases in the percentage of stable aggregates, the levels of the total and water-soluble C fractions, microbial biomass C, basal respiration, and the activity of the different enzymes involved in the biogeochemical cycles of C, N, and P. The results confirm the usefulness of sewage sludge as an organic amendment for recovering damaged soils.
由于有机质流失以及随之而来的保护性植被缺乏，地中海地区的土壤极易遭受侵蚀。在本实验中，对坡度为15%的地中海退化土壤以250吨/公顷湿重的用量施入污水污泥以及污水污泥与大麦秸秆的混合物（污水污泥含碳70%，秸秆含碳30%），以研究它们对土壤结构恢复的影响，进而研究土壤对侵蚀过程的抗性。两种有机改良剂都使几种土壤性质（物理、生物和微生物性质）得到改善，这是由于改良三个月后自发生长的植物覆盖层变得明显。这种植被在两年的实验期间一直存在，防止了通常先于土壤退化的水蚀过程。与对照土壤相比，仅施用污水污泥使土壤流失减少了80%，而包含污水污泥和大麦秸秆的混合物使流失减少了84%，两者均使径流减少了57%。改良后的土壤中稳定团聚体百分比、总碳和水溶性碳组分含量、微生物生物量碳、基础呼吸以及参与碳、氮和磷生物地球化学循环的不同酶的活性均有所增加。结果证实了污水污泥作为恢复受损土壤的有机改良剂的有效性。
