• 资源生态 •

### 黄土丘陵区退耕地生物结皮对土壤理化性状的影响

1. 1. 中国科学院,水利部水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,北京100101;
2. 中国科学院地理科学与资源研究所 陕西杨凌712100;
3. 西北农林科技大学水土保持研究所,陕西杨凌712100
• 收稿日期:2005-10-21 修回日期:2005-12-03 出版日期:2006-06-25 发布日期:2006-06-25
• 作者简介:赵允格（1971），女，陕西咸阳人，副研，博士，主要从事土壤生物结皮及土壤水分、养分运移方面的 研究工作。E-mail: zyunge@ms.iswc.ac.cn
• 基金资助:

中科院“西部之光”人才培养计划项目;国家自然科学青年基金项目(40401026、40301028);中科院“百人计划”项目

### Impact of Biological Soil Crust on Soil Physical and Chemical Properties of Rehabilitated Grassland in Hilly Loess Plateau,China

ZHAO Yun-ge1,2, XU Ming-xiang1,2, WANG Quan-jiu1,2, SHAO Ming-an1,3

1. 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation, CAS and MWR,Yangling 712100,China;
2. Institute of Soil and Water Conservation,Northwest Agriculture and Fotrestry University,Yangling 712100,China;
3. Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China
• Received:2005-10-21 Revised:2005-12-03 Online:2006-06-25 Published:2006-06-25

Abstract: Biological soil crust plays an important role in degraded ecosystem restoration.Large area of biological crust has formed after cropland shifting to revegetated grassland on the hilly Loess Plateau of China. Our objective was to determine the impact of biological crust on soil chemical and physical properties in the study area.In this paper,through field investigation and sampling analysis,some physical and chemical properties of different years rehabilitated grasslands on the northern slopes which had biological soil crust formed on the surface were studied.Eight research sites were selected and soil and crust samples were collected in April 2004,with the restriction that locations were confined to a single soil series that was representative of the local environmental condition,similar elevation and slope.At each sampling site,five samples taken randomly were mixed to form a composite soil sample.Samples were taken from the 0 to 20 cm deep profile in 6 layers(crust,0-2,2-5,5-10,10-15 and 15-20cm).Soil moisture,bulk density,cohesion of soil surface,infiltration rate,organic matter content,total nitrogen,total phosphorus and available N,P,K contents of the 0-20cm soil profile were measured for soil samples taken from the 8 sites.The results showed soil physical and chemical properties of the 0-20cm profile were affected significantly by the biological crust.1)After shifting from cropland to revegetated grassland,soil moisture in the 0-20cm profile increased firstly and then decreased with the increase of rehabilitation years.Because the formation of the biological crust,soil penetrability of the rehabilitated grasslands reduced significantly compared with cropland,this also resulted in lower soil moisture in this profile after 10 years' rehabilitation.2)Soil surface cohesion of the rehabili-tated grassland increased significantly with the formation of the biological crust after shifting from cropland.After 10 years revegetation,the crusted soil surface cohesion of the revegetated grassland was 6 times that of the fresh revegetated grassland.The reason for this was mainly due to the formation of the biological crust,rather than the increase of soil bulk density.3)Soil penetrability reduced significantly when shifting from cropland to revegetated grassland.The infiltration coefficient of crusted soil decreased gradually with the increase in years of revegetation.However,the infiltration coefficient increased gradually when getting rid of the crust.4)The formation of the biological crust brought to an enrichment of soil organic matter and total nitrogen in the upper soil.With the increased years of rehabilitation,the enrichment was even more obvious,and soil total phosphorus was also enriched to some extent.Soil available nutrient was improved as a result of the formation of the biological crust.