[Soil Health Evaluation of Non-grain Cultivated Land Based on Soil Quality Index Area Method and Soil Sensitivity-resistance Method： A Case Study of Ningbo City].

The aim of this study was to understand the soil health status of non-grain cultivated land in Ningbo， identify the main obstacle factors of non-grain cultivated land， explore the effect of non-grain on soil quality， and construct a comprehensive soil health evaluation system of non-grain cultivated land in Ningbo. Taking the soil of control cultivated land and typical non-grain cultivated land in Ningbo as the research object， 268 surface soil samples of 0-20 cm were collected under the utilization of control cultivated land， orchards， and nursery-grown plants. The 22 indexes of soil physics， chemistry， biology， and heavy metals were determined； the minimum data set was constructed by using principal component analysis， correlation analysis， and Norm value； and the soil health evaluation system in Ningbo was constructed using the soil quality index area method and soil sensitivity-resistance method， combined with soil multifunctionality to judge the quality of non-grain cultivated land in Ningbo. The results showed that： ① Compared with the soil of control cultivated land， soil bulk density （BD） in orchards and nursery-grown plants increased significantly （P<0.05）， while the contents of organic carbon （SOC）， total nitrogen （TN）， available phosphorus （AP）， available copper （ACu）， soil extracellular enzyme activity， and soil microbial biomass carbon （MBC） decreased significantly （P<0.05）. ② The minimum data set for soil health evaluation of non-grain cultivated land in Ningbo consisted of BD， electrical conductivity （EC）， SOC， dissolved organic carbon （DOC）， tammonium nitrogen （NH₄⁺-N）， TN， available iron （AFe）， available manganese （AMn）， and acid phosphatase （Phos）. The minimum data set verified by the total data set could reflect the effective information of non-grain soil quality in Ningbo. ③ Based on the soil quality index area method， the content of SOC， TN， AFe， AMn， and Phos in the cultivated land under non-grain utilization was lower than that of the control cultivated land. ④ According to the sensitivity and resistance analysis， the soil sensitive indexes included SOC， DOC， NH₄⁺-N， TN， AFe， and AMn， and the resistance index was BD and EC. ⑤ The random forest model showed that TN， SOC， N-acetyl-β-D-glucosidase （NAG）， and Phos were the main driving factors of soil multifunctionality index， while AFe， AMn， Phos， and DOC were the main driving factors of soil quality index. On the whole， the soil quality index and soil multifunctionality index of the two non-grain planting methods were lower than those of the control cultivated soil. Therefore， this study determined the health status of non-grain soil in Ningbo， identified the main obstacle factors of non-grain cultivated land， and provided some data support and theoretical basis for the classification and renovation of non-grain cultivated land and ensuring food security in Ningbo.