关键词: 养分循环, 数据管理, 概念模型

Abstract: Soil samples of five land-use types, including cropland, shrubbery, secondary forest, grassland, and abandoned cropland, were collected in Puding County in June 2016, which is a typical karst critical zone in Southwest China. Spatial distribution of total phosphorus (TP) and available phosphorus (Olsen-P) in soils were investigated. We further analyzed the controlling factors of spatial variation of soil P, including pH, soil organic carbon (SOC), total nitrogen (TN), and aggregate composition. The results showed the contents of TP and Olsen-P decreased with increasing of soil depth, and the variations were more obvious in the upper 30 cm than those in the lower 30 cm. The TP and Olsen-P contents were different under cropland from other land use types due to the impacts of human activity. The Olsen-P contents were very low except for the secondary forest soils. The positive correlations were observed between the contents of TP, Olsen-P, SOC and TN, with the best correlation coefficients being found in the cropland. The SOC contents were the most important factor affecting TP and Olsen-P contents. The high contents of organic matters facilitated the absorption of P in crops. The proportion of macro-aggregates was dominant in the most soils, which were positively correlated with TP and Olsen-P contents, indicating that the increases of the proportion of macro-aggregates promoted soil P accumulation.

Key words: Nutrients cycling, Data management, Conceptual model