Influence of planting methods and organic amendments on rice yield and bacterial communities in the rhizosphere soil

Abstract

A comprehensive understanding of rice cultivation techniques and organic amendments affecting soil quality, enzyme activities and bacterial community structure is crucial. We investigated two planting methods (direct seeding and transplanting) of paddy rice (Oryza sativa) and organic amendments with rice straw and biochar on crop yield and soil biological and physicochemical properties. Rhizosphere bacterial communities at the maturity stage of rice growth were characterized through high-throughput 16S rRNA sequencing. Soil biochemical properties and enzyme activity levels were analyzed. Grain yield of paddy rice with transplanting increased 10.6% more than that with direct seeding. The application of rice straw increased grain yield by 7.1 and 8.2%, more than with biochar and the control, respectively. Compared to biochar and the control, the application of rice straw significantly increased sucrase, cellulase, protease, organic carbon, available phosphorus, nitrate, and ammonium. The application of biochar increased microbial biomass nitrogen and carbon, urease, pH, available nitrogen, and available potassium compared to the application of rice straw and the control. Principal coordinate analysis and dissimilarity distances confirmed significant differences among the microbial communities associated with planting methods and organic amendments. Bacteroidetes, Nitrospirae, Firmicutes, and Gemmatimonadetes abundance increased with rice straw relative to biochar and the control. The biochar addition was associated with significant increases in Chloroflexi, Patescibacteria, Proteobacteria, and Actinobacteria abundance. Pearson’s correlation analyzes showed that Chloroflexi, Bacteroidetes and Nitrospirae abundance was positively correlated with grain yield. The relative abundance of these bacteria in soil may be beneficial for improving grain yield. These results suggest that planting methods and organic amendments impact soil biochemical characteristics, enzyme activity levels, and microbial community composition.

Straw and Biochar Application Alters the Structure of Rhizosphere Microbial Communities in Direct-Seeded Rice (Oryza sativa L.) Paddies

“…As shown in Figure 5, RS amendment also led to improvements in soil microbial community structure relative to the BC and CK. BC provided high levels of C and an environmental niche compatible with the growth of these root-associated microbes, owing to its stable, porous structure [50]. BC can offer a habitat in which microbes can grow while also influencing the structure and diversity of these rhizosphere soil communities [8].…”

“…The relatively high Gemmatimonas abundance may have resulted from the decomposition of straw over time, given that these bacteria can serve as indirect drivers of cellulose degradation [53]. BC application has previously been associated with increases in relative Actinobacteria abundance in rice paddies [50,54], and members of this phylum have been shown to be present in soil rich in organic matter, particularly under slightly alkaline or neutral conditions [55]. Biochar can facilitate soil N immobilization, which can then be slowly released over time as nutrients are absorbed by the roots of rice plants.…”

Impacts of various amendments on the microbial communities and soil organic carbon of coastal saline–alkali soil in the Yellow River Delta

“…Some research studies have shown that Bacteroidetes and Firmicutes can produce hydrolases (including β-1,4-xylosidase and β-glucosidase) to break down plant biomass (Rao et al, 2021 ). Previous reports classified Bacteroidetes and Firmicutes as copiotrophs (Tang et al, 2022 ), which use labile forms of C for growth and metabolism and grow faster in a nutrient-rich environment.…”

Long-Term Chemical Fertilization Drove Beneficial Bacteria for Rice Soil to Move from Bulk Soil to the Rhizosphere

“…The roots were forcibly shaken with sterile forceps to separate the roots from the soil, and then five soil samples from each plot were mixed together to generate a composite sample. Finally, all of the soil separated from the roots was sieved by using a 2 mm mesh sieve and put into a sterile zip-lock bag [35,36].…”

“…The extraction, PCR amplification, and sequencing of the total genomic DNA of the soil samples were completed according to previous protocols [36]. The primer pair 515F (5 -GTGCCAGCMGCCGCGGTAA-3 ) and 806R (5 -GGACTACHVGGGTWTCTAAT-3 ) was used to amplify the soil bacterial 16S rRNA gene in the V4 hypervariable region [38,39].…”