Abstract:

To evaluate soil single factor and comprehensive fertility through mathematical method, eight indicators including pH, total nitrogen, total potassium, total phosphorus, alkali hydrolysed nitrogen and available potassium were selected as evaluation criteria. Descriptive statistical method and fuzzy comprehensive evaluation model were used to analyze and evaluate single-factor and comprehensive fertility indicators respectively. The results showed that the soil in the study area was mainly alkaline or strongly alkaline, with a mean pH of 7.78 and a coefficient of variation of 6.56%, indicating relatively high stability of soil acidity and alkalinity. Soil nitrogen and available potassium were relatively high, but total potassium, total phosphorus and available phosphorus were relatively low, and the total organic matter content was moderate. Through the evaluation model, it was found that organic matter had the greatest effect on total fertility, while available potassium had the least effect on total fertility. In addition, the distribution of soil comprehensive fertility levels was relatively scattered, with first and second class land accounting for 24.49%, third class land accounting for 26.02%, and poor fourth and fifth class land accounting for 49.49%. In conclusion, the results of this study could provide useful reference for local agricultural production and soil management. Based on the single-factor level of soil nutrients and the comprehensive level of fertility, fertilization plans and crop management measures could be formulated. Future research should consider more factors and indicators, further improve the soil fertility evaluation model, and improve the accuracy and reliability of the evaluation.

Key words: Dingqing County, Tibet, soil fertility, single factor evaluation, comprehensive fertility evaluation, fuzzy comprehensive evaluation method