Microbial Responses to the Reduction of Chemical Fertilizers in the Rhizosphere Soil of Flue-Cured Tobacco

Abstract

The overuse of chemical fertilizers has resulted in the degradation of the physicochemical properties and negative changes in the microbial profiles of agricultural soil. These changes have disequilibrated the balance in agricultural ecology, which has resulted in overloaded land with low fertility and planting obstacles. To protect the agricultural soil from the effects of unsustainable fertilization strategies, experiments of the reduction of nitrogen fertilization at 10, 20, and 30% were implemented. In this study, the bacterial responses to the reduction of nitrogen fertilizer were investigated. The bacterial communities of the fertilizer-reducing treatments (D10F, D20F, and D30F) were different from those of the control group (CK). The alpha diversity was significantly increased in D20F compared to that of the CK. The analysis of beta diversity revealed variation of the bacterial communities between fertilizer-reducing treatments and CK, when the clusters of D10F, D20F, and D30F were separated. Chemical fertilizers played dominant roles in changing the bacterial community of D20F. Meanwhile, pH, soil organic matter, and six enzymes (soil sucrase, catalase, polyphenol oxidase, urease, acid phosphatase, and nitrite reductase) were responsible for the variation of the bacterial communities in fertilizer-reducing treatments. Moreover, four of the top 20 genera (unidentified JG30-KF-AS9, JG30-KF-CM45, Streptomyces, and Elsterales) were considered as key bacteria, which contributed to the variation of bacterial communities between fertilizer-reducing treatments and CK. These findings provide a theoretical basis for a fertilizer-reducing strategy in sustainable agriculture, and potentially contribute to the utilization of agricultural resources through screening plant beneficial bacteria from native low-fertility soil.

Optimal NPK Fertilizer Combination Increases Panax ginseng Yield and Quality and Affects Diversity and Structure of Rhizosphere Fungal Communities

“…These results provide a theoretical basis to develop efficient cultivation of ginseng. In future studies, the following should be considered: (i) soil bacterial communities also have important effects on crop growth (Shen et al, 2022 ), and how they affect ginseng cultivation should be investigated; (ii) mechanisms by which soil fungi stimulate the production of secondary metabolites in ginseng rhizomes need further investigation; and (iii) whether precise NPK combined application can increase long-term benefits and also alleviate problems caused by mineral fertilizers on soil fungi and soil functions needs further in-depth and systematic research.…”

“…However, prolonged, excessive, and unscientific fertilization methods have led to a series of ecological problems. The problems include soil pollution and destruction of microbial community structure, especially that of communities involved in nitrogen (N), phosphorus (P), and carbon (C) cycles, which lead to declines in crop growth and yield (Pavlidis et al, 2020 ; Shen et al, 2022 ). Fertilization also greatly affects microbial populations associated with potassium (K) and iron (Fe) cycles (Bose et al, 2014 ).…”

Functional organic fertilizers can alleviate tobacco (Nicotiana tabacum L.) continuous cropping obstacle via ameliorating soil physicochemical properties and bacterial community structure

“…There was an apparent improvement in soil AP content, which caused the change of microbiomes to some degree. It is well-known that soil pH is a crucial factor that influences microbial composition and diversity in soil physicochemical properties ( Chen et al, 2018b ; Bai et al, 2019 ; Shen et al, 2022 ). Specifically, soil pH takes a role in bacterial diversity by changing their osmotic pressure and surface potential directly, and indirectly the bioavailability of nutrients and the habitation conditions ( Chen W et al, 2018 ; Bai et al, 2019 ).…”

Differences in microbial diversity and environmental factors in ploughing-treated tobacco soil

“…The original soil samples were screened through an 18-mesh sieve (1 mm diameter) to avoid fine roots, plant residues, stones, and other stones. And the samples were stored in a refrigerator at −80°C for subsequent experimental analysis ( Brow et al, 2010 ; Rissanen et al, 2010 ; Shen et al, 2021 ; Zhang Y. et al, 2021 ; Wang et al, 2022 ). After air drying, the basic physicochemical properties and enzyme activities of the soil were determined, including pH, water content (WC), total nitrogen (TN), soil organic matter (SOM), available phosphorus (AP), available potassium (AK), sucrase (S-SC), urease (UE), catalase (CAT), polyphenol oxidase (PPO), nitrate reductase (NR), and acid phosphatase (ACP) ( Wang et al, 2019 ).…”