Amount of decomposed cattle manure application combined with chemical fertilizer control soil microbial diversity and community structure on rain-fed farmland

The results show that the different fertilization treatments significantly increase the soil nutrient content compared to CK, with the MF2 treatment having the highest. In contrast to the CK treatment, soil organic matter, available phosphorus, available potassium and total nitrogen were significantly increased in the MF2 treatment by 5.84%, 112.16%, 52.13% and 16.88%, respectively. Compared to CK, F, MF1, MF2 and SF treatments decreased soil bacterial diversity and richness, while MF1 and MF2 treatments increased soil fungal diversity and richness. The BG and ALP activities in the MF2 treatment increased by 95.32% and 22.38%, respectively, compared to the F treatment, while the NAG and CBH activities in the SF treatment increased by 44.10% and 17.18%, respectively, compared to the F treatment.For the microbial community, the MF2 treatment increased the relative abundance of the soil bacteria Chloroflexi and Acidobacteria, and the soil fungi Mortierellomycota and Basidiomycota. The results of the structural equation model (SEM) indicated that in soils amended with mature cow manure, the quantity of water-stable aggregates with a diameter greater than 0.25 mm (R0.25), soil organic matter (SOM), β-Glucosidase (BG) activity, and Alkaline Phosphatase (ALP) activity were the primary factors influencing the soil bacterial Chao1 index and Shannon index, while R 0.25 and ALP activity were the main factors affecting the fungal Observed species index. Overall, 50%chemical fertilizer combined with decomposed cow manure (MF2) exhibited highest soil fertilization and microbial diversity, it could be a proposing approach to sustainable development of local dryland farming system.