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| Application of Le Bissonnais method to study soil aggregate stability in the Hilly-gully region |
| Guo Man1,2,Zheng Fenli1,2,An Shaoshan1,2,Liu Yu1,2,Wang Bin1,Frederic Darboux3 |
1.College of Resources and Environment,Northwest A & F University;2.State Key Laboratory of Soil Erosion and Dry-land Farming in Loess
Plateau,Institute of Soil and Water Conservation CAS & MWR :712100,Yangling,Shaanxi,China;3.Institut National de la Recherché Agronomique,UR 272 Soil Science,45075,Orleans,France |
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Abstract Soil aggregate stability is a key indicator for soil quality evaluation.The transition area from forest to grassland zone of the Hilly-gully region,located in Yangou Catchments in Yan'an City,was taken as a research site.Soil samples from six vegetation types during vegetation natural restoration were used to measure soil water-stable aggregate using Le Bissonnais(LB) method,and compared the results of LB 3-treatments with the Yoder method.The results showed that,in the 3-treatments(fast wetting,slow wetting,and wetting stirring) of LB method,fast wetting(FW) was the most destructive degree to the soil aggregate stability,the distribution of soil water-stable aggregate mainly concentrated in 0.05-0.5 mm;slow wetting(SW) was the least destructive degree to soil aggregate stability,soil water-stable aggregate content was mainly >2 mm;the destructive degree of soil aggregate structure by wetting stirring(WS) was between FW and SW treatments,the soil water-stable aggregates size was well-distributed.It was explained that the primary destructive mechanism of soil aggregate structure was dissipation.During the period of 100a of abandoning cropland,the succession process of vegetation experience is annual herbaceous(4 a)—perennial herbaceous(16 a)—semi shrub(29 a)—shrub(55 a)—arbor(100 a).With the succession process of vegetation,soil water-stability aggregate size shifted from small size to large size,soil structure was improved.The correlation between >0.5 mm soil aggregate content or mean weight diameter(MWD) measured by FW or SW and soil organic carbon or physical clay content was significantly different;but for WS treatment,there was no significant different between soil aggregate content or MWD and soil organic carbon or physical clay content.This result showed that soil organic matter and physical clay content mainly influenced dissipation and disintegration by clay swelling and mechanical stirring had no significant impacts on soil aggregate stability.Comparing with the Yoder method,SW and Yoder method have highly comparability,and SW treatment of LB method was suitable to measure soil water-stable aggregate during vegetation restoration in the Hilly-gully region.
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Received: 12 October 2009
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