Data_Sheet_1_Soil Bacterial Community in the Multiple Cropping System Increased Grain Yield Within 40 Cultivation Years.docx

The shortage of land resources restricts the sustainable development of agricultural production. Multiple cropping has been widely used in Southern China, but whether the continuous planting will cause a decline in soil quality and crop yield is unclear. To test whether multiple cropping could increase grain yield, we investigated the farmlands with different cultivation years (10–20 years, 20–40 years, and >40 years). Results showed that tobacco-rice multiple cropping rotation significantly increased soil pH, nitrogen nutrient content, and grain yield, and it increased the richness of the bacterial community. The farmland with 20–40 years of cultivation has the highest soil organic carbon (SOC), ammonium nitrogen, and grain yield, but there is no significant difference in the diversity and structure of the bacterial community in farmlands with different cultivation years. The molecular ecological network indicated that the stability of the bacterial community decreased across the cultivation years, which may result in a decline of farmland yields in multiple cropping system> 40 years. The Acidobacteria members as the keystone taxa (Zi ≥ 2.5 or Pi ≥ 0.62) appeared in the tobacco-rice multiple cropping rotation farmlands, and the highest abundance of Acidobacteria was found in the farmland with the highest SOC and ammonium nitrogen content, suggesting Acidobacteria Gp4, GP7, GP12, and GP17 are important taxa involved in the soil carbon and nitrogen cycle. Therefore, in this study, the multiple cropping systems for 20 years will not reduce the crop production potential, but they cannot last for more than 40 years. This study provides insights for ensuring soil quality and enhancing sustainable agricultural production capacity.

土地资源的稀缺性限制了农业生产的可持续发展。在中国南方，多熟制耕作已被广泛应用，然而，连续种植是否会导致土壤质量下降和作物产量减少尚不明确。为检验多熟制是否能够提升粮食产量，我们针对不同耕作年限的农田（10-20年、20-40年以及超过40年）进行了研究。结果表明，烟稻轮作的多熟制显著提高了土壤pH值、氮素营养含量以及粮食产量，并丰富了细菌群落。耕作年限为20-40年的农田具有最高的土壤有机碳（SOC）、铵态氮和粮食产量，但不同耕作年限的农田在细菌群落的多样性和结构上并无显著差异。分子生态网络分析显示，细菌群落的稳定性随耕作年限的增加而降低，这可能导致超过40年的多熟制耕作系统中农田产量的下降。作为关键类群（Zi ≥ 2.5或Pi ≥ 0.62）的酸杆菌在烟稻轮作农田中出现，且在SOC和铵态氮含量最高的农田中酸杆菌的丰度最高，这表明酸杆菌Gp4、GP7、GP12和GP17是参与土壤碳氮循环的重要类群。因此，本研究表明，20年的多熟制耕作系统不会降低作物生产潜力，但它们无法持续超过40年。本研究为保障土壤质量、提升可持续农业生产能力提供了重要启示。