Soil health evaluation in the intensive vineyard based on minimum data set

Healthy soils can provide the essential ecosystem services for food security and nutrition, climate, and sustainable development. Soil management practices can be optimized to promote the soil productivity and ecological balance for the high-yield and high-quality grapes in intensive grape production. This study aims to investigate the soil health status in the intensive vineyards in Quzhou County, Hebei Province, China. The soil samples were then collected in October 2020. A total of 42 vineyards were sampled in 0-20 cm soil depth. Twenty physical, chemical, and biological indicators were determined, including soil water content, surface hardness, subsurface hardness, bulk density, wet aggregate stability, pH, total nitrogen, available P and K, exchangeable Ca and Mg, available Fe, Mn, Cu and Zn, exchangeable Na, soil organic carbon, permanganate oxidizable carbon, soil protein, and respiration. The principal component analysis was used to establish the minimum dataset for the soil health evaluation in the intensive vineyards. Two evaluation approaches, Linear (L) and non-linear (NL) scoring functions, were used to calculate the soil health index. The limiting factors were also identified in the vineyards. The results revealed that six indicators were selected for the minimum dataset by the principal component analysis, including the soil organic carbon, soil subsurface hardness, exchangeable sodium, bulk density, water content, and wet stability aggregate. There was a significant positive correlation (P<0.01) between the soil health index with the total data set and the minimum dataset with linear and nonlinear scoring functions. Alternatively, the minimum dataset was used to better replace the total dataset, in order to assess the soil health in vineyards. According to the minimum dataset, the soil health indices ranged from 0.39-0.59 and 0.36-0.66 with average values of 0.52 and 0.51 using linear and nonlinear scoring functions, respectively, indicating the medium level. The soil health indices in the average tree age of 6, 13, and 22 were 0.64-0.65 and 0.50-0.53 using linear and non-linear scoring functions using the minimum dataset, respectively. No significant difference was observed in the soil health index among vines of different tree ages. The soil surface hardness, subsurface hardness, and bulk density in the vineyards were 1 203 kPa, 1 023 kPa, and 1.42 g/cm³, respectively, indicating a medium compaction level. Soil available P and K, exchangeable Ca and Mg, and available Fe and Zn were all at the rich level. The average content of soil organic carbon was 8.33 g/kg with a range of 5.6-13.1 g/kg, which was at the deficiency level. Therefore, the major soil obstacles in the intensive vineyards mainly included soil compaction, nutrient imbalance, and low organic carbon content. The agricultural measures can be implemented to reduce the frequency of field management in the optimal utilization of organic or bio-organic fertilizers, and cover crop planting, as well as the integrated nutrient. These approaches can be expected to enhance the soil health level in the sustainable development of local grape industries.