Elucidating the impact of biochar with different carbon/nitrogen ratios on soil biochemical properties and rhizosphere bacterial communities of flue-cured tobacco plants

Abstract

Background and aimsIn agriculture, biochar (BC) and nitrogen (N) fertilizers are commonly used for improving soil fertility and crop productivity. However, it remains unclear how different levels of BC and N fertilizer affect soil fertility and crop productivity.MethodsThis study elucidates the impact of different application rates of BC (0, 600, and 1200 kg/ha) and N fertilizer (105 and 126 kg/ha) on biomass accumulation, soil microbial biomass of carbon (SMC) and nitrogen (SMN), and soil biochemical properties, including soil organic carbon (SOC), total nitrogen (TN), soil nitrate nitrogen (NO3−−N), ammonium nitrogen (NH4+−N), urease (UE), acid phosphatase (ACP), catalase (CAT), and sucrase (SC) of tobacco plants. In addition, a high throughput amplicon sequencing technique was adopted to investigate the effect of different application rates of BC/N on rhizosphere bacterial communities of tobacco plants.ResultsThe results confirm that high dosages of BC and N fertilizer (B1200N126) significantly enhance dry matter accumulation by 31.56% and 23.97% compared with control B0N105 and B0N126 under field conditions and 23.94% and 24.52% under pot experiment, respectively. The soil biochemical properties, SMC, and SMN significantly improved under the high application rate of BC and N fertilizer (B1200N126), while it negatively influenced the soil carbon/nitrogen ratio. Analysis of rhizosphere bacteriome through amplicon sequencing of 16S rRNA revealed that the structure, diversity, and composition of rhizosphere bacterial communities dramatically changed under different BC/N ratios. Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Acidobacteria were highly abundant bacterial phyla in the rhizosphere of tobacco plants under different treatments. Co-occurrence network analysis displayed fewer negative correlations among rhizosphere bacterial communities under high dosages of biochar and nitrogen (B1200N126) than other treatments, which showed less competition for resources among microbes. In addition, a redundancy analysis further proved a significant positive correlation among SMC, SMN, soil biochemical properties, and high dosage of biochar and nitrogen (B1200N126).ConclusionsThus, we conclude that a high dosage of BC (1200 kg/ha) under a high application rate of N fertilizer (126 kg/ha) enhances the biomass accumulation of tobacco plants by improving the soil biochemical properties and activities of rhizosphere bacterial communities.

Transcriptome profiling reveals the impact of various levels of biochar application on the growth of flue-cured tobacco plants

“…Biochar and fertilizer (base fertilizer) were thoroughly mixed into the soil in planting holes before transplanting seedlings. After field preparation, tobacco seedlings (50 days old) were transplanted in the planting holes on the ridges with plant × row spacings (60 cm × 120 cm) [ 28 ]. The experiment was conducted under five treatments: no BC (0 kg/ha; CK), 600 kg/ha BC (A1), 900 kg/ha BC (A2), 1200 kg/ha BC (A3), and 1800 kg/ha BC (A4).…”

“…A study on Chinese cherries treated with tobacco straw BC revealed that genes related to phytohormones such as abscisic acid, indole acetic acid and gibberellins were regulated, and photosynthesis was also promoted [ 22 ]. Several studies have reported the growth-promoting effect of BC at lower dosages and the inhibition of growth at higher dosages [ 28 ], but the underlying molecular mechanisms are poorly understood. Therefore, transcriptomics may allow us to study key genetic factors and pathways involved in the growth promotion of tobacco under different BC application rates.…”

Metagenomic insights into the response of soil microbial communities to pathogenic Ralstonia solanacearum

“…The soil samples were transported to the laboratory, where they were allowed to air dry at ambient temperature before being crushed and put through a 2 mm screen. The methods of soil physical and chemical analysis (1978;Yang et al, 2023) were followed in performing the soil physicochemical analysis. In particular, two stages of drying were used to measure the water content of the soil (per 100 g fresh weight).…”

Exploring the effect of different application rates of biochar on the accumulation of nutrients and growth of flue-cured tobacco (Nicotiana tabacum)

“…The effect of biochar on soil physicochemical properties and plant growth varies depending on the nature and application rate of the biochar (Yang et al, 2023). Biochar amendment in the soil at a certain level can promote the growth and biomass of flue-cured tobacco, while higher application of biochar harms plant growth (Zhang et al, 2016).…”