( 4 ) co2 concentration in soil reached to maximum at 13 o ' clock in forest land which is with both high elevation and low elevation , the curves are single kurtosis ; co2 concentration in soil reached to minimum at both 13 o ' clock and 22 o ' clock in the bare land which is with high elevation , the curve is double kurtosis , and that in the low elevation reached to maximum at 16 o ' colck , its curve is single kurtosis ( 4 )两个海拔高度区内两乔木样地内的土壤coz都于13 : 00出现峰值，呈单峰形态;高海拔地区的裸地土壤c0 :在13 : 00和22 : 00出现最低值，呈双峰型，低海拔地区的裸地土壤coz在16 : 00出现最高值，曲线形态为单峰型。
The results indicate that : purification efficiency of phenol was better of wetland soil in which was not reed - planted ; both the residence time of phenol in soil and the range of particle size affected the adsorption ability of wetland soil ; through changing soil infiltration and physicochemical properties of rhizosphere , reed can affect adsorption ability of wetland soil on phenol 结果表明，未生长芦苇的湿地土壤对苯酚具有较好的净化效果；苯酚在土壤中滞留时间、土壤的粒径范围均影响湿地土壤对苯酚的吸附能力；芦苇能改变土壤入渗率和根际土壤的理化性质，从而影响湿地土壤对苯酚的吸附能力。
Based on analysis of soil physical , chemical and biological properties , soil properties and soil integrated fertility index ( iff ) of different successional series of subalpine coniferous in western sichuan were systematically studied . the results showed soil fertility degradation of subalpine coniferous forests was mainly related to decrease of soil organic matter 从土壤物理、化学和生物学性质角度出发，系统地研究了四川西部亚高山针叶林不同演替阶段土壤性质和土壤综合肥力指标值，结果表明：川西亚高山针叶林土壤性质主要受土壤有机质的影响，人工林地土壤肥力质量退化主要由于有机质的减少并导致相关土壤物理、化学和生物学性质恶化。
Through the analyses of characteristics of gully thalweg and soil erosion in upland and gully land , sediment sources in small watershed , sediment yield relationship between upland and gully and ecological functions of vegetation corridor , it is considered that vegetation corridor combined with land preparation measures may block runoff and sediment from upland and reduce the amount of soil erosion in a watershed by 54 . 5 % ~ 77 . 0 % 摘要在分析黄土高原地区的沟沿线、沟沿线上下沟间地和沟谷地土壤侵蚀特征、小流域泥沙来源、坡沟侵蚀产沙关系的基础上，结合廊道的生态功能和以往的研究结果，认为在沟沿线的上部建立草灌与整地工程措施相结合的植物廊道，来拦蓄阻截沟间地的来水来沙，可使流域的土壤侵蚀量减少54 . 5 % ~ 77 . 0 % 。
As china ' s increasing population continues to exert pressure on the natural resources and environment in china , issues related to the evolution of soil quality - and in particular soil fertility - have become an increasing focus of worldwide concern . the primary objective of this dissertation is to identify the determinants of changes in soil fertility and quality in china in the period from the early 1980s to 2000 . after describing measures for soil fertility and quality , the study examines the possible impact of socio - economic factors on soil fertility and quality , especially land tenure institutions governing tenure security and land transfer rights 本研究的目的就是期望能够较为准确地判断80年代初到2000年中国东部地区农业土壤肥力的变动趋势，使人们对目前土壤肥力状况有较为清楚客观的认识；在此基础上，考察社会经济及政策因素特别是农地产权制度中地权不稳定、不完整的土地交易权等对农地土壤肥力的这种变化有何影响，为决策者和政策制定者提供科学的理论依据，帮助他们有的放矢的地调整制度和政策，最终不断改善土壤的可持续生产能力，有效地保障国家的粮食安全。
The results show that the majority of 7be is retained in the top one centimeter of soils , and the concentration of 7be decreases exponentially with soil depth . for the cultivated study field , the depth distribution of 7be is very similar to the undisturbed site when it is n ' t subjected to erosion or deposition . for the undisturbed , there is abroad peak in the 137cs profile close to the surface and the maximum concentration is found circa 2 cm below the surface ~ ( 137 ) cs在未扰动土壤剖面中主要分布在0 5cm范围内，同时在1 3cm的范围出现一个~ ( 137 ) cs的相对富集层，在3cm以下随土壤深度的增加呈指数递减的趋势； ~ ( 137 ) cs在农耕地土壤剖面中主要分布在0 20cm范围内，由于耕作活动的不断扰动~ ( 137 ) cs的剖面分布相对均匀。
