Soil quality in east coastal region of China as related to different land use types

Purpose The impacts of different land use practices on soil quality were assessed by measuring soil attributes and using factor analysis in coastal tidal lands. The study provided relevant references for coastal exploitation, land management and related researches in other countries and regions. Materials and methods Measured soil attributes include physical indicators [bulk density (rho(b)), total porosity (f(t)) and water-holding capacity (WHC)], chemical indicators [pH, electrical conductivity (EC), total nitrogen (TN), soil organic matter (SOM), available N, available P and available K] and biological indicators (urease activity, catalase activity and phosphatase activity), and 60 soil samples were collected within five land use types [(1) intertidal soils, (2) reclaimed tidal flat soils, (3) farmland soils, (4) suburban vegetable soils, (5) industrial area soils) in Jianggang village of Dongtai county, Jiangsu province of China. Results and discussion The results from the investigation indicated that selected soil properties reduced to three factors for 0-20-cm soil depth; "Soil fertility status" (factor 1), "Soil physical status" (factor 2) and "Soil salinity status" (factor 3). For the first factor, the measured soil attributes with higher loadings were TN and SOM, which represented soil fertility feature, and for the second and third factors, the measured soil attributes with higher loadings were rho(b) and available K as well as EC, which reflected soil physical properties and soil salinity feature, respectively. Conclusions Changes in different land use types due to plants (corn, wheat and green vegetable) and application of fertilizers were characterized by promoted soil quality, including improvements in chemical properties (increasing SOM concentration, TN and nutrient available to plants; decreasing EC), improvements in soil physical properties (decreasing rho(b); increasing f(t) and WHC) and enhancements in soil enzyme activities. Judging from the soil quality indices, the soil quality was affected by different land use practices and decreased in sequence of suburban vegetable soils, farmland soils, industrial area soils, reclaimed tidal flat soils and intertidal soils in the study area.