Effects of Bacterial Fertilizer and Green Manure on Soil Enzyme Activity and Root Characteristics in Korla Fragrant Pear Orchard

Zhanyi HeJie LiLele YangLinsen YanBolang ChenXing Shen^*Zhongping Chai^*

• Xinjiang Agricultural University, Ürümqi, China

To systematically evaluate the effects of bacterial fertilizer and different types of green manure on the rhizosphere ecological functions and yield formation of Korla fragrant pear (Pyrus brestschneideri Rehd.), a field experiment was conducted in a Korla pear orchard. Six treatments were established: bacterial fertilizer (JF), two planting densities of sweet clover (CMX1, CMX2), two planting densities of oil sunflower (DK1, DK2), and a control (CK). Their impacts on soil physicochemical properties, enzyme activity, root structure, and yield were analyzed. The results showed that both bacterial fertilizer and green manure significantly reduced soil pH and EC and improved soil nutrient content and enzyme activity. Bacterial fertilizer was more effective in enhancing enzyme activity, whereas green manure, particularly sweet clover, was more effective in improving soil properties. Sweet clover reduced soil pH and EC and increased available nutrients, while oil sunflower was more effective in increasing soil organic matter. For both green manures, low density outperformed high density. Both bacterial fertilizer and green manure promoted Root activity, decreased cortex thickness, and increased vessel area, with bacterial fertilizer showing the greatest effect, followed by sweet clover and oil sunflower. High-density sweet clover and low-density oil sunflower achieved better outcomes within their treatments. Sweet clover and bacterial fertilizer also increased the proportion of cellulose cell wall cells in xylem and phloem, with sweet clover outperforming bacterial fertilizer. Yield was improved by both bacterial fertilizer and green manure, with bacterial fertilizer achieving the highest increase, though not significantly different from green manure. The PLS-SEM model indicated that bacterial fertilizer and green manure enhanced root structure and Root activity, ultimately improving yield by reducing soil pH and EC and increasing soil nutrients and enzyme activity. Root activity was identified as a key mediator. Based on goals of improving soil fertility, promoting root growth, increasing yield, and achieving cost-effectiveness and green production, CMX1 is recommended as the optimal management practice. These findings provide scientific support for sustainable pear production in arid regions and broaden perspectives on root ecological regulation.