Introduction: In arid regions, soil degradation and nutrient scarcity limit the productivity of Korla fragrant pear (Pyrus bretschneideri Rehd.). This study aimed to systematically evaluate how bacterial fertilizer and different green manures affect rhizosphere ecological functions and yield formation.Methods: A field experiment was conducted in a Korla pear orchard with six treatments: bacterial fertilizer (JF), two planting densities of sweet clover (CMX1, CMX2), two planting densities of oil sunflower (DK1, DK2), and a control (CK). Soil physicochemical properties, enzyme activities, root architecture, and yield were analyzed.Results: Both bacterial fertilizer and green manures significantly reduced soil pH and EC, improved nutrient content, and enhanced enzyme activity. Bacterial fertilizer was more effective in boosting enzyme activity, while sweet clover excelled in improving soil properties. Low-density green manures outperformed high-density ones. Root activity, vessel area, and yield were significantly increased by all amendments, with bacterial fertilizer showing the strongest effect. PLS-SEM analysis identified root activity as a key mediator linking soil improvements to yield gains.Discussion: These results highlight the critical role of root activity in translating soil amendments into yield benefits. Among all treatments, low-density sweet clover (CMX1) offers the most cost-effective and sustainable strategy for improving soil fertility and pear yield in arid orchards.

The sustainability of Korla fragrant pear orchards has been increasingly threatened by prolonged intensive agricultural practices. In response, biofertilizers and green manures have gained attention due to their potential to enhance soil structure, activate microbial functions, and improve nutrient uptake. However, the dynamic changes in soil bacterial communities under such interventions remain inadequately understood. This study was conducted from 2022 to 2023 in 7- to 8-year-old Korla fragrant pear orchards in Bayin’guoleng Mongol Autonomous Prefecture, Xinjiang. The treatments included: conventional fertilization (CK), biofertilizer (JF), oil sunflowers (DK1) with 25 cm row spacing and a seeding rate of 27 kg·hm⁻², oil sunflowers (DK2) with 25 cm row spacing and a seeding rate of 33 kg·hm⁻², sweet clover (CM1) with 20 cm row spacing and a seeding rate of 21 kg·hm⁻², and sweet clover (CM2) with 20 cm row spacing and a seeding rate of 27 kg·hm⁻². During the 2023 pear season, soil samples from the 0–20 cm layer were collected at the fruit setting, expansion, and maturity stages. Their physical and chemical properties were analyzed, and the structure and diversity of the soil bacterial community were examined using 16S rRNA gene high-throughput sequencing. Fruit yield was assessed at the maturity stage. Compared to CK, the relative abundance of Actinobacteria increased by 101.00%, 38.99%, and 50.38% in the JF, DK2, and CM1 treatments, respectively. DK1 and CM1 treatments resulted in a 152.28% and 145.70% increase in the relative abundance of the taxon Subgroup_7, while JF and DK2 treatments enhanced the relative abundance of the taxon Gitt-GS-136 by 318.91% and 324.04%, respectively. The Chao1 index for CM2 was 18.76% higher than CK. LEfSe analysis showed that the DK2 and CM2 treatments had a more significant regulatory effect on bacterial community structure. All treatments led to higher fruit numbers and yield compared to CK, with JF showing the largest yield increase. Fertilizer type, soil nutrients, and bacterial community structure all significantly positively influenced pear yield. In conclusion, high-density oil sunflower planting is the most effective approach for maintaining soil microbial community stability, followed by low-density sweet clover. This study provides a systematic evaluation of the dynamic effects of bio-fertilizers and different green manure planting patterns on soil microbial communities in Korla fragrant pear orchards, presenting practical, microbe-based strategies for sustainable orchard management.

Korla Fragrant Pear(Pyrus sinkiangensis Yu), a high-value Geographical Indication product from Xinjiang, China, faces declining fruit quality due to soil degradation from intensive monoculture. This study investigated microbial fertilizer (JF) and green manure (oil sunflower - DK1, DK2; sweet clover - CM1, CM2) intercropping in a pear orchard to improve soil and fruit quality, compared to conventional fertilization (CK). Comprehensive analyses assessed soil properties, fruit minerals, metabolites (monosaccharides, fatty acids, amino acids), and volatile organic compounds (VOCs).Both JF and green manure treatments improved soil physicochemical properties, with CM1 showing the greatest effect. Treatments JF, CM1, CM2, DK1, and DK2 significantly increased fruit K, P, Fe, and Mn content but significantly decreased Zn content. JF significantly enhanced monosaccharide accumulation, while CM1 and high-density oil sunflower (DK2) notably increased fatty acid and free amino acid content. However, all treatments (JF, CM1, CM2, DK1, DK2) significantly reduced total fruit VOCs. Correlation analysis indicated fruit Zn content was positively correlated with most VOCs. Reduced Zn inhibited alcohol dehydrogenase (ADH) and copper-zinc superoxide dismutase (Cu/Zn SOD) activity, leading to decreased VOC synthesis. Therefore, while CM1 is recommended as the optimal strategy for improving basic nutritional quality and soil fertility, coordinated zinc nutrition management is essential when implementing green manure to balance nutritional enhancement with maintaining characteristic flavor, ensuring sustainable industry development.

Excessive use of nitrogen fertilizer affects the sustainable development of the Korla fragrant pear orchard. Semi-decomposed sheep manure is favored because of its advantages of being pollution-free, containing more microorganisms, and being friendly to soil. However, the effects of nitrogen fertilizer combined with sheep manure on soil nutrient cycling and microbial community in pear orchards are still unclear. This study involved a two-year field experiment to investigate fertilization’s effects on the 0–20 cm soil layer of 10–12-year-old Korla fragrant pear trees at maturity. The purpose of this study was to explore the effect of reducing nitrogen fertilizer combined with sheep manure on soil fertility and microbial community in Korla fragrant pear orchard. The treatments of no nitrogen fertilizer (N0), conventional fertilization (N), 20% reduction in nitrogen based on conventional fertilization (N2), a combination of 20% nitrogen reduction with sheep manure F1 (22,500 kg·hm⁻²), and 20% nitrogen reduction with sheep manure F2 (33,750 kg·hm⁻²) formed the experimental treatment of nitrogen reduction with sheep manure, denoted as N2F1 and N2F2. The results showed that nitrogen application increased soil physicochemical indicators but decreased soil pH and bacterial community richness and diversity. After nitrogen reduction, soil total nitrogen (TN), alkaline hydrolysis nitrogen (AN), available phosphorus (AP), microbial biomass nitrogen (SMBN), bacterial community richness, fungal community evenness, and diversity were inhibited, but bacterial community diversity was increased. Nitrogen reduction combined with sheep manure treatment increased the content of nitrate nitrogen (NO₃⁻–N), ammonium nitrogen (NH₄⁺–N), soil organic matter (SOM), pH, microbial biomass carbon (SMBC), and SMBN and increased the evenness and diversity of the bacterial community but inhibited the richness of the bacterial community. Among them, N2F2 treatment had the best effect on SMBC and SMBN. Soil pH, NO₃⁻–N, and SOM were the primary environmental variables influencing bacterial and fungal community levels. The application of nitrogen significantly influenced pear orchard yields, but the yield of pears treated showed no significant variation with nitrogen reduction and nitrogen reduction combined with sheep manure based on complete nitrogen application. In summary, 20% nitrogen reduction (300 kg·hm⁻²) combined with 22,500–33,750 kg·hm⁻² sheep manure better promotes the stability and health of soil microbial communities, and the use of organic fertilizer represents the most efficient approach to quickly enhancing soil fertility and the variation of microbial communities. These findings are highly relevant when improving land productivity, ensuring food security, and promoting environmental sustainability in fruit tree farming.