Spatial changes in soil chemical properties in an agricultural zone in southeastern China due to land consolidation

摘要

Land consolidation, an active land management technique to improve the rural infrastructure, has been widely adopted in China since 1999. It is very critical to investigate the changes in soil properties in cultivated land before and after land consolidation. This study evaluated the effect of land consolidation on soil changes across an agricultural area in southeastern China. Topsoil samples were collected from cultivated land in a typical agricultural zone of 731 km(2) in 2003 (before land consolidation, n = 312) and in 2008 (after land consolidation, n = 665). A linear mixed model with spatio-temporal correlation was used to predict the distribution of five soil properties (pH, soil organic matter, total N, available P and available K) during this period. The distributions of soil properties predicted by the linear mixed model showed a smaller spatial variation in soil properties after land consolidation. This was most likely due to the mixture of topsoil with subsoil. This soil redistribution caused an increase in pH in some areas, while it decreased in other parts. Soil organic matter and total N decreased and they were affected by soil texture. Available P and K were also declined, mostly due to the recent decrease in application level of chemical fertilizers. The results indicated that the spatial changes in soil properties should be investigated after land consolidation for developing management strategies to sustain soil fertility and avoid soil degradation.