Comparison of soil microbial community and physicochemical properties between rice–fallow and rice–bean (green manure) rotation

Abstract

Rice (Oryza sativa L.)–fallow and rice–green manure rotation are two common ecological rotation modes in the Lower reaches of the Yangtze River Basin. In this study, based on a long‐term positioning field experiment, soil microbial community structure (bacteria and fungi) and physicochemical properties were investigated and compared to comprehensively evaluate the effects of rice–fallow (RF) and rice–bean (Vicia faba L.) (green manure, RB) rotation on soil health, thus providing scientific basis for the utilization mode of paddy field in winter. The results showed that (a) compared with RF, the contents of soil organic matter (SOM), humic acid (HA), total N, and soil alkaline phosphatase in RB were significantly enhanced by 33.84, 71.04, 35.48, and 54.38%, respectively (p < .01); available K content in RF was increased by 22.84% compared with RB (p < .01); (b) the soil macroaggregates with a diameter more than 0.25 mm (R0.25), mean weight diameter, and geometric mean diameter (GMD) in RB treatment were significantly higher than those of RF by 112.67, 60.25, and 64.88%, respectively (p < .05); (c) different rotations altered bacterial community structure significantly, but exhibited less effect on that of fungi; bulk density, pH, GMD, SOM, and HA were the key environmental factors shaping the bacterial and fungal community structure. The alteration of specific bacterial and fungal taxa revealed that RB had a more promising potential to promote crop growth and improve organic matter decomposition. Therefore, rice–green manure rotation demonstrated a stronger positive effect on soil physicochemical and microbial properties.

Response of Rice Grain Yield and Soil Fertility to Fertilization Management under Three Rice-Based Cropping Systems in Reclaimed Soil

“…Numerous studies have indicated the benefits of green manure rotation in enhancing soil fertility and increasing crop yields [30,46]. However, in this study, the rice grain yield was found to be highest in the rice-fallow rotation system, which contradicts our hypothesis regarding the highest yield in the rice-green manure rotation system.…”

“…Specifically, we focused on three rice-based cropping systems: rice-wheat rotation, ricegreen manure rotation, and rice-fallow rotation. It is hypothesized that in a rice green manure rotation system, the ample application of organic fertilizers would result in the highest soil fertility and rice grain yield and increased microbial activity associated with carbon [30]. Additionally, we proposed that using organic fertilizers with lower carbon-tonitrogen ratios would further enhance these effects.…”