National Engineering Laboratory of Applied Technology for Forestry & Ecology in Southern China, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China; College of Forestry, College of Soil and Water Conservation, Central South University of Forestry & Technology, Changsha, 410004, Hunan, China.
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China.
J Environ Manage. 2024 Dec;371:123131. doi: 10.1016/j.jenvman.2024.123131. Epub 2024 Nov 6.
An understanding of how irrigation regimes affect autotrophic microorganisms is essential, as this has direct implications for the soil organic carbon (SOC) content, rice yield and the sustainable agricultural practices. Here, the effects of three irrigation regimes on autotrophic microorganisms, soil active organic carbon fractions, and rice yield were explored. The irrigation regimes were: 1) rainfed (RF), 2) midseason drying (MD), and 3) continuous flooding (CF). The SOC, microbial biomass carbon (MBC), MBC/SOC ratio, dissolved organic carbon (DOC), DOC/SOC ratio, the cbbL (the cbbL gene encodes the large subunit of ribulose-1, 5-bisphosphate carboxylase) bacterial alpha diversity and community composition, and rice yield were assessed under each regime. The highest MBC content (646 mg kg in the early season and 1007 mg kg in the late season) and MBC/SOC ratio (3% in the early season and 5% in the late season) were observed under the RF regime. The soil DOC content and DOC/SOC ratio were the highest in the MD regime, followed by the CF regime. The lowest values were observed under the RF regime, with greater differences observed in the late season. Soil cbbL bacterial alpha diversity was the highest in the MD regime and the lowest in the CF regime. The irrigation regimes altered the composition of the cbbL microbial community, with Burkholderiales and Corynebacteriales exhibiting the highest relative abundances in the MD regime. In the late season, the rice yield in the MD regime was 53% and 14% greater than the RF and CF regimes, respectively. A partial-least-squares path model showed that the optimal regime (MD regime) increased the alpha diversity of the soil cbbL bacteria and the relative abundances of several probiotic microorganisms. This, in turn, increased soil DOC content and its contribution to SOC, eventually increasing the rice yield. These findings clarified the effects of different water management strategies on autotrophic microorganisms, organic carbon, and rice yield, providing guidance for implementing suitable water management practices to enhance soil fertility and rice yield.
了解灌溉制度如何影响自养微生物至关重要，因为这直接影响土壤有机碳（SOC）含量、水稻产量和可持续农业实践。在这里，研究了三种灌溉制度对自养微生物、土壤活性有机碳组分和水稻产量的影响。灌溉制度为：1）雨养（RF）、2）中期干旱（MD）和 3）连续淹水（CF）。评估了每个制度下的 SOC、微生物生物量碳（MBC）、MBC/SOC 比、溶解有机碳（DOC）、DOC/SOC 比、cbbL（cbbL 基因编码核酮糖-1,5-二磷酸羧化酶的大亚基）细菌 α多样性和群落组成以及水稻产量。RF 制度下的 MBC 含量最高（早季 646mg/kg，晚季 1007mg/kg）和 MBC/SOC 比最高（早季 3%，晚季 5%）。MD 制度下的土壤 DOC 含量和 DOC/SOC 比最高，其次是 CF 制度。RF 制度下的最低值，晚季差异较大。MD 制度下的土壤 cbbL 细菌 α多样性最高，CF 制度下的最低。灌溉制度改变了 cbbL 微生物群落的组成，其中伯克霍尔德氏菌科和棒状杆菌科在 MD 制度下的相对丰度最高。在晚季，MD 制度下的水稻产量分别比 RF 和 CF 制度高出 53%和 14%。偏最小二乘路径模型表明，最优制度（MD 制度）增加了土壤 cbbL 细菌的 α多样性和几种益生菌微生物的相对丰度。这反过来又增加了土壤 DOC 含量及其对 SOC 的贡献，最终增加了水稻产量。这些发现阐明了不同水管理策略对自养微生物、有机碳和水稻产量的影响，为实施适宜的水管理实践以提高土壤肥力和水稻产量提供了指导。
