Effects of long-term sisal residue returning on soil physiochemistry, microbial community, and sisal yield

Returning agricultural waste/by-products to the field is an effective management measure to improve soil fertility and maintain crop productivity in agroecosystems. However, we still have limited understanding of the complex response of sisal ( Agave sisalana Perrine) growth, soil nutrients and microbial communities to the long-term sisal residue return to the ecological system. This study aimed to investigate the comprehensive effects of returning sisal residue to the field on sisal yield, soil nutrient, and microbial community. Based on a four-year field experiment, the results showed that returning sisal residue to the field increased the annual yield of sisal by 30.77-33.36%. Compared with control group, sisal residue inputs significantly improved soil total nitrogen, available phosphorus, and available potassium by 46.59, 3.02, and 1.21%, respectively. Under sisal residue input condition, the activities of soil catalase, urease, acid phosphatase, and sucrase also significantly increased by 2.01, 17.20, 17.40 and 16.60%, respectively. A higher ratio of bacteria/fungi was observed in the soil amended with sisal residue. The microbial diversity analysis showed that the alpha-diversity of the bacterial community increased, while the alpha-diversity of the fungal community decreased with the sisal residue treatment. However, sisal residue return had a higher impact on the alpha-diversity of fungi. This study provides evidence that returning sisal residue to the field affects sisal productivity by regulating nutrient cycling and soil microbial community. Moreover, the study suggests that microbial alpha-diversity has significant influence on sisal yield.