Rice-straw mat mulching improves the soil integrated fertility index of apple orchards on cinnamon soil and fluvo-aquic soil

Abstract

Mulching management have been proposed for protecting the soil surface in farmland. This study was a three-year field experiment to evaluate the effects of rice-straw mat mulching (RSMM) on the soil integrated fertility index (IFI). We measured the soil total organic carbon (TOC) and labile carbon fractions, and soil microbial community functional diversity in cinnamon soil and fluvo-aquic soil orchards. The RSMM significantly increased the contents of soil TOC, particulate organic carbon (POC), easily oxidized carbon (EOC) and available phosphorus (AP) in both orchards. Additionally, the soil light fraction organic carbon (LFOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC) contents, and soil urease activity were significantly increased in the cinnamon soil orchard, and the soil alkaline nitrogen (AN) and available potassium (AK) contents increased in the fluvo-aquic soil orchard under RSMM. The microbial metabolic utilization of carbohydrates and amino acids, and the soil microbial functional diversity and apple fruit quality were improved by RSMM, while the microbial communities under RSMM had different metabolic functions in the two orchards. A comprehensive evaluation of soil quality based on the weighted coefficients determined by a principal component analysis of 17 fertility indicators showed that RSMM increased the IFI by 97.9 and 138.5 % in the cinnamon soil and fluvo-aquic soil orchards, respectively. The study demonstrated that RSMM can effectively improve the soil IFI by altering the soil organic carbon content and microbial community diversity, with the effects being more sensitive for the fluvo-aquic soil orchard than the cinnamon soil orchard.