High manure load reduces bacterial diversity and network complexity in a paddy soil under crop rotations

Abstract

Long-term application of chemical fertilizers causes soil degradation and nitrogen (N) loss, but these effects could be alleviated by organic fertilizers. In addition, crop rotation is a feasible practice to increase soil fertility, soil quality and crop yields comparing with monocultural cropping patterns. However, questions remain concerning how the soil microbiome responds to different manure application rates under crop rotations. Here, we collected soil samples from a rice-rape system to investigate the response of the soil microbiome to nine years of pig manure application at different rates (CK: 0 kg ha-1 , M1: 1930 kg ha-1 , M2: 3860 kg ha-1 and M3: 5790 kg ha-1). Our results revealed that the bacterial α-diversity (Chao1 and Shannon index) in the rape season increased first and then decreased with increasing manure application rates, and a high manure load tended to decrease the bacterial α-diversity in the rice season. Long-term manure application enriched some copiotrophic bacteria, such as Proteobacteria and Actinobacteria, while it decreased the relative abundance of Nitrospirae. Redundancy analysis (RDA) and the Mantel test indicated that soil pH, TC, TN, AP, C/P and N/P ratios were the main factors influencing bacterial communities. Moreover, network analysis showed that a low manure application rate shaped a complexly connected and stable bacterial community, while higher manure application rate decreased the stability of the bacterial network. These findings improve our understanding of bacterial responses to longterm manure application under crop rotations and their relationships with soil factors, especially in the context of increasing fertilizer inputs.

Bio-Organic Fertilizers Manipulate Abundance Patterns of Rhizosphere Soil Microbial Community Structure To Improve Tomato Productivity

“…4). Our results are similar to the previous study by Liu et al (2020) which reported that 40 g/kg manure application rate decreased the stability of the bacterial network. Given the important role of environmental selection in community assembly, B. subtilis CY1 could speci cally select microbial populations with fewer interactions due to niche differentiation after organic fertilizer application.…”

Organic amendments alleviate early defoliation and increase fruit yield by altering assembly patterns and of microbial communities and enzymatic activities in sandy pear (Pyrus pyrifolia)

“…When the composition of soil microbial communities change, as they do when fertilization practices change, the microbial co-occurrence network changes as well (Ling et al 2016 ; Ramirez et al 2018 ). Network topology parameters have been used as biological indicators of the adaptability of microorganisms in response to fertilization disturbances (Ji et al 2020 ; Li et al 2020a ; Liu et al 2020a ). In our field test, we found that application of BIO (+ BIO) and HA (+ HA) reduced the modularity of the co-occurrence network of bacteria and fungi (Fig.…”

Soil pH Filters the Association Patterns of Aluminum-Tolerant Microorganisms in Rice Paddies

“…Microbial network analysis has been widely used to explore microbial associations in complex environments ( 25 – 27 ). Although a cooccurrence network may not always reflect true ecological associations ( 28 , 29 ), it can help to understand how the complexity of microbial community changes in response to environmental factors ( 30 – 32 ). Recently, a directed network has been used to infer the directionality of associations in ecology networks ( 33 – 35 ).…”