Objective  Revealing the changes of soil quality after economic turf planting in different years is the basis for ensuring the rapid and accurate improvement of turf planting paddy field reclamation.

  Method  Based on the improvement needs of nearly 133.3 hm² of paddy field in Dingqiao Town, Haining, which needs to be reclaimed into paddy field after economic turf planting. The soils after turf planting in paddy field for different years (0, 1, 2, 3 and 4 years) were selected as the research object to analyze the mechanical composition, bulk density, pH value, organic matter and cation exchange capacity (CEC) of the soils. Total amounts of nitrogen, phosphorus and potassium and their available contents were tested, and the correlations and comprehensive evaluation of soil fertility were analyzed, in order to explore the characteristics of soil physicochemical properties and nutrient indices, and to clarify the changes of key fertility factors in paddy field after economic turf planting.

  Result  After turf planting in paddy field, with the increase of turf planting years, the change trends of physicochemical properties and nutrient content indices of soil at different depths (0-15 cm, 15-30 cm, 30-45 cm) were consistent. With the increase of turf planting years, the contents of soil sand decreased, the content of clay increased, the bulk density increased, the pH gradually increased, and the soil organic matter and CEC decreased first fast and then slow. The contents of total soil and available nitrogen, phosphorus and potassium decreased gradually, especially in the early stage of turf planting. The contents of total and available nutrients and the content of soil sand particles were significantly negatively correlated with the years of turf planting (P < 0.01), the changes of soil pH, bulk density and clay content were significantly positively correlated with the years of turf planting (P < 0.01), and the changes of organic matter and CEC were significantly negatively correlated with the years of turf planting (P < 0.05), The comprehensive grade of soil fertility degenerated to the barren level.

  Conclusion  The economic turfgrass planting in paddy field leads to the significant degradation of soil fertility.