Ziyuan Kexue (Nov 2023)
The influence of non-grain conversion of cultivated land on soil health and mechanism: Taking rural-urban fringe area of Xuzhou City as an example
Abstract
[Objective] This study aimed to explore the potential damage of non-grain conversion of cultivated land on soil health, and provide a scientific basis for evaluating the impact of non-grain conversion on land productivity and ecological functions. [Methods] 80 surface soil samples were randomly collected from six types of non-grain conversion land, including facility vegetable field, orchard, poplar forest, grassland, highway landscape forest, and fallow land, and the control farmland in the rural-urban fringe area of Xuzhou City through field survey, sampling analysis, model evaluation, and statistical analysis. A total of 23 indicators of soil physical, chemical, and biological properties, as well as heavy metal pollution were measured to construct the cultivated land health assessment model, to explore the impact of non-grain conversion on land productivity and soil health. [Results] The results show that: (1) Non-grain conversion significantly changed soil physio-chemical and biological characteristics. The activities of cellulose disaccharide hydrolase, alkaline phosphatase, and bacterial diversity index in non-grain conversion soil were significantly lower than those in the soil of the control site (P < 0.05). The soil organic matter content (27.92-36.33 g·kg-1), total phosphorus (0.89-1.54 g·kg-1), available phosphorus (186.82-307.01 mg·kg-1), available potassium (199.09-305.03 mg·kg-1), and total nitrogen and nitrate nitrogen content in facility vegetable plots were the highest, and there were significant differences (P < 0.05) compared to the other five non-grain conversion land use types; (2) Compared to the farmland control site, the six types of non-grain conversion land use have led to some imbalance of different soil functions including productivity, water retention and purification, carbon sequestration, nutrient cycling, and biodiversity, even resulting in a suboptimal health state; (3) The structural equation model fitting result shows that soil nutrients, enzyme activity, biodiversity, and heavy metal pollution index dominated the soil health differentiation of non-grain conversion sites. [Conclusion] Non-grain conversion had an impact on cultivated land health, while there were considerable differences in health damage among different land uses. The results provide some reference for targeted management of non-grain conversion of farmland and safeguarding food security.
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