Study On Spatial Variability Of Soil Quality And Site-specific Management Of Soil Nutrient In A Vegetable Production Area

A better understanding of spatial variability of nutrients and heavy metals in soil and vegetable is required as a basis of soil nutrient site-specific management and rational fertilizer application for high quality and high yield vegetable production. However, soil nutrient and heavy metal status, especially spatial variability in vegetable fields and corresponding nutrient management approaches have not been studied systematically in China. This study was conducted to determine soil nutrient spatial variability and its influencing factors, spatial variability and plant availability of soil heavy metals, evaluation of nutrient balance in soil-vegetable system and response of site-specific balanced fertilization in a vegetable production area of 55 hm² using modern and advanced technologies and approaches. The main results obtained were summarized as follows:1 Soil nutrient spatial variability and its influencing factorsSoil nutrient limiting factors were N, P, K and Zn. Obvious semi-variance structures of spatial variability was observed for soil NO₃^--N, available P, K and Zn, with the range of spatial correlation of 204-348 m. Significant spatial distribution similarity was found for soil NO₃^--N, P, K and Zn. Soil NO₃^--N, P and K content was closely and positively correlated with vegetable production history and fertilizer application rates (N, P₂O₅ and K₂O). Insignificant difference in status and spatial distribution of soil nutrients was observed under two grid-sampling scales (50 m × 50 m and 100 m × 100 m), suggesting that soil nutrient status of the study area could be evaluated using soil sampling on a 100 m × 100 m grid, with low cost in soil sampling and soil testing.2 Spatial variability and plant availability of soil heavy metalsHigher contents of soil Cd was found in this vegetable production area, with...