Long-term organic fertilization alters soil microbial community structure and its influence on faba bean production in a six-crop rotation system

Fertilization significantly impacts soil chemical and microbial properties, ultimately influencing soil productivity and crop yield. However, the effects of long-term (40 years) fertilization strategies on soil microbial communities in crop-rotation systems are not well understood.

This study examines changes in soil chemical properties, microbial communities, and faba bean yield under different chemical and organic fertilization treatments. Nine treatments were tested: a control (CK), nitrogen alone (N), nitrogen and phosphorus (NP), nitrogen and potassium (NK), NPK, organic fertilizer (M), MN, MNP, and MNPK.

Results showed that organic fertilizer treatments significantly enhanced soil organic matter, nutrient content, and faba bean yield. The increase in soil fertility and faba bean yield was positively correlated with bacterial and fungal alpha diversity. Different fertilization practices also altered microbial community composition, forming three distinct groups: CK and chemical fertilization treatments were clustered closer, while organic fertilizer-added treatments were obviously separated from them. Soil total carbon and nitrogen, organic matter and available phosphorus were key factors influencing microbial community structures. Four keystones were identified: g_MND1, o_Rokubacteriales, g_UTCFX1, and f_SC-I-84, all of which belong to bacteria, playing a crucial role in soil carbon and nitrogen transformation.

This study highlights the prominent role of organic fertilizer in enhancing soil fertility, crop yield and microbial diversity, contributing to the productivity and sustainability of agricultural ecosystems.