Mitigating soil degradation in continuous cropping banana fields through long-term organic fertilization: Insights from soil acidification, ammonia oxidation, and microbial communities

Abstract

Exploring the potential of organic fertilizers as a mitigating strategy against the negative consequences induced by prolonged use of inorganic fertilizers in high-intensity banana cultivation is critically essential. Ammonia-oxidizer are closely linked to soil acidification, and how they respond to the long term fertilized banana field soil still poorly understood. In this study, soil samples from long-term inorganic (CF), and inorganically plus organically fertilized banana fields (OF) (from 2010 to 2019) were used to investigate the soil acid buffer capacity (pHBC), the potential nitrification rate (PNR), and the community structure of bacteria, fungi, ammonia-oxidizing archaea (AOA), and bacteria (AOB). Compared to the natural soil (CK, unplanted, and unfertilized), the pH and pHBC in the long-term fertilized banana field (both CF and OF) were significantly reduced. However, the pHBC was 1.3 times higher in soil receiving OF treatment than that in CF treatment. Organic matter (OM) and total nitrogen (TN) were significantly increased in the OF treated soil, which were 1.88 and 1.6 times higher compared to the CF-treated ones. The PNR in banana soil was 3.71–4.85 times higher than in the natural soil. High-throughput sequencing results showed that Candidatus Nitrosospharea SCA1170-like AOA and Nitrosospira spp-like AOB were adapted to long-term fertilization in banana field soil. Potentially pathogenic bacteria, Xanthomonadaceae, were enriched in CF-treated soil compared to CK and OF soils. Opposingly, potentially beneficial Streptomyces and Arthrobacter were enriched in natural soil. Meanwhile, the OF-treated soil demonstrated a greater abundance of beneficial Bacillus and Alicyclobacillus. The study reveals that organic fertilizers ameliorate soil acidification, low organic matter content and microbial diversity compared to inorganic fertilizers for banana cultivation.