Bacterial communities in paddy soil and ditch sediment under rice-crab co-culture system

Xu Jiang,Hui Ma,Jun Yang,Cai-Yun Xin,Qing-Lei Zhao,Bocong Chen

doi:10.1186/s13568-021-01323-4

Abstract

As an important form of sustainable agriculture, rice-crab (Eriocheir sinensis) co-culture is rapid developing worldwide. However, the knowledge on the bacterial communities of the different components of the system is limited. In this study, we investigated the bacterial community structure in paddy soil and ditch sediment by using high-throughput sequencing technology. The results showed that compared with the ditch sediment, the content of NH4+-N in paddy soil decreased by 62.31%, and the content of AP (available phosphorus) increased by 172.02% (P < 0.05). The most abundant phyla in paddy soil and ditch sediment were Proteobacteria, Bacteroidetes and Chloroflexi, whose relative abundance was above 65%. Among the dominant genera, the relative abundance of an uncultured bacterium genus of Saprospiraceae and an uncultured bacterium genus of Lentimicrobiaceae in paddy soil was significantly lower than ditch sediment (P < 0.05). Alpha diversity indicated that the bacterial diversity of paddy soil and ditch sediment was similar. The bacterial community structure was affected by the relative abundance of bacteria, not the species of bacteria. Redundancy analysis (RDA) showed that the bacterial communities in paddy soil and ditch sediment were correlated with physicochemical properties. Our findings showed that the bacterial community structure was distinct in paddy soil and ditch sediment under rice-crab co-culture probably due to their different management patterns. These results can provide theoretical support for improving rice-crab co-culture technology.

Highlights

IntroductionRice-fish co-culture integrates rice farming and aquaculture, which cultures animals (e.g., fish, crayfish, and crab) in a paddy field during the rice planting time
Rice-fish co-culture integrates rice farming and aquaculture, which cultures animals in a paddy field during the rice planting time
Physicochemical properties of paddy soil and ditch sediment As shown in Table 1, the content of TN, TP, AN and AP in paddy soil were higher than those in ditch sediment, especially the content of AP was significantly increased by 172.02% (P < 0.05)

Summary

Introduction

Rice-fish co-culture integrates rice farming and aquaculture, which cultures animals (e.g., fish, crayfish, and crab) in a paddy field during the rice planting time. Due to the extra production of aquaculture, farmers’ income has increased and farmers have become more receptive to the rice-fish co-culture system (Smajgl et al 2015; Xie et al 2011; Zhang et al 2016). The fish reduced the occurrence of insect pests and weeds, which fertilized the paddy field (Zheng et al 2017; Zhang et al 2010). The rice-fish co-culture system composes of two parts: paddy and ditch. The water quality index of paddy field and ditch were distinct under the rice-crayfish (Procambarus clarkii) system (Yu et al 2018). The water quality index of paddy field and ditch were distinct under the rice-crayfish (Procambarus clarkii) system (Yu et al 2018). Zhao et al (2017) found that the biodiversity of the paddy field was higher than

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