Effects of Different Planting Years on Soil Physicochemical Indexes, Microbial Functional Diversity and Fruit Quality of Pear Trees

This study explores the interaction between pear fruit quality and the soil environment over four different planting years (5, 20, 30, and 40 years), focusing on the fruit’s chemical properties, rhizosphere soil properties, microbial communities, and both microbiomass and functional diversity. The results found that reducing sugar, sucrose, and vitamin C contents in pears initially increased with planting years before declining, while total acidity showed an inverse trend. Analysis of the soil physicochemical index revealed that rhizosphere soil physicochemical indexes were significantly different between different planting years, but there was no obvious regularity. Correlation analysis found that total phosphorus, total potassium, organic matter, and available nitrogen were significantly and positively correlated with pear quality indexes. Soil microbiomass carbon decreased before increasing with increasing planting year, while soil microbial nitrogen was irregular. Results of functional diversity of rhizosphere soil bacterial communities showed that the relationship of carbon source utilization among the six groups was 20 years > 5 years > 30 years > 40 years. Interestingly, the 20-year group had the most core differences in microbial communities. The study suggests that as pear trees age, adequate plant nutrition during peak fruiting periods can improve soil fertility, microbial functional diversity, and ultimately enhance fruit quality.