Abstract:
Establishing a new method to assess soil fertility of cultivated land using less input and cost without reducing any useful information is helpful to guide agricultural production and land use planning. In this study, four administrative cities in southern Dongting Lake River Basin were selected as the study area. The 14 indices representing four main components, such as site conditions, soil profile properties, soil physical properties and soil nutrients were comprehensively considered. Soil fertility was evaluated by the integrated index based on the minimum data set (MDS) using principal component analysis, and its main limiting factors was also analyzed. The results showed that the study area was mainly slightly acidic. Soil bulk density (BD) and the nitrogen nutrient presented trends of slightly tight and at a higher level, respectively. The phosphorus nutrient ranged from the medium to high level, and the potassium nutrient was at a low level. The MDS was consist of seven indices, including soil parent material, soil profile pattern, CEC, BD, SOM, AP and TK. The mean and standard deviation of total data set (TDS) and MDS were close with a Pearson’s correlation efficient of 0.788 (
P < 0.01). The areas with high soil fertility index (SFI) were mainly located in the concentrated rice planting area near the southern Dongting Lake water system. Those with low SFI were mainly distributed in the hilly area with relatively high altitude or low vegetation coverage close to urban construction area. Phosphorus and potassium nutrients were the main limiting factors of SFI in the study area. The results provided a theoretical guidance for the comprehensive assessment and improvement of soil fertility in the southern Dongting Lake Basin.