scholarly journals Impact of an intercropped melon/cowpea system on the coupling between soil bacterial community structure and chemical properties

Author(s):  
Jessica Cuartero ◽  
Jose Antonio Pascual ◽  
Juana-María Vivo ◽  
Onurcan Özbolat ◽  
Virginia Sánchez-Navarro ◽  
...  

Abstract A greater understanding of the relationship between soil microorganisms and intercropping systems could contribute to the optimization of land use, fostering sustainable and efficient agriculture. This study entails a comparative intercropping assay using cowpea (Vigna unguiculata) and melon (Cucumis melo) under organic management with different patterns and 30% less organic fertilization than that used in monocrops in the first year. The intercropping system changed the bacterial community structure independently of the intercropping pattern and contributed to an increase in soil nitrogen, phosphorous content and melon crop yield. The intercropped systems were characterized by a higher abundance of Pseudomonas (Proteobacteria), which are related to nutrient cycling, and other beneficial microorganisms.

Author(s):  
Yaoben Lin ◽  
Yanmei Ye ◽  
Shuchang Liu ◽  
Jiahao Wen ◽  
Danling Chen

Farmland consolidation is an effective tool to improve farmland infrastructures, soil quality, and sustain a healthy farmland ecosystem and rural population, generating contributions to food security and regional sustainable development. Previous studies showed that farmland consolidation regulates soil physical and chemical properties. Soil microorganisms also play an important role in soil health and crop performance; however, few studies reported how farmland consolidation influence soil microecology. Here, we used DNA sequencing technology to compare bacterial community structure in farmlands with and without consolidation. DNA sequencing technology is the most advanced technology used to obtain biological information in the world, and it has been widely used in the research of soil micro-ecological environment. In September 2018, we collected soil samples in Jiashan County, Zhejiang Province, China, and used DNA sequence technology to compare the bacterial community structure in farmlands with and without consolidation. Our results found that (1) farmland consolidation had significant impacts on soil microbial characteristics, which were mainly manifested as changes in microbial biomass, microbial diversity and community structure. Farmland consolidation can increase the relative abundance of the three dominant bacteria phyla and the three fungal dominant phyla, but it also negatively affects the relative abundance of the six dominant bacteria phyla and the three fungal dominant phyla. (2) Farmland consolidation had an indirect impact on soil bacterial community structure by adjusting the soil physical and chemical properties. (3) The impact of heavy metals on bacterial community structure varied significantly under different levels of heavy metal pollution in farmland consolidation areas. There were 6, 3, 3, and 5 bacterial genera that had significant correlations with heavy metal content in cultivated land with low pollution, light pollution, medium pollution, and heavy pollution, respectively. The number of heavy metal-tolerant bacteria in the soil generally increased first and then decreased under heavy metal polluted conditions. Our study untangled the relationship between varied farmland consolidation strategies and bacteria through soil physcicochemical properties and metal pollution conditions. Our results can guide farmland consolidation strategies and sustain soil health and ecological balance in agriculture.


2021 ◽  
Vol 12 ◽  
Author(s):  
Quanqing Deng ◽  
Taobing Yu ◽  
Zhen Zeng ◽  
Umair Ashraf ◽  
Qihan Shi ◽  
...  

Silicon (Si) deficiency, caused by acidic soil and rainy climate, is a major constraint for sugarcane production in southern China. Si application generally improves sugarcane growth; however, there are few studies on the relationships between enhanced plant growth, changes in rhizosphere soil, and bacterial communities. A field experiment was conducted to measure sugarcane agronomic traits, plant nutrient contents, rhizosphere soil enzyme activities and chemical properties, and the rhizosphere bacterial community diversity and structure of three predominant sugarcane varieties under two Si treatments, i.e., 0 and 200 kg of silicon dioxide (SiO2) ha−1 regarded as Si0 and Si200, respectively. Results showed that Si application substantially improved the sugarcane stalk fresh weight and Si, phosphorus (P), and potassium (K) contents comparing to Si0, and had an obvious impact on rhizosphere soil pH, available Si (ASi), available P (AP), available K (AK), total phosphorus (TP), and the activity of acid phosphatase. Furthermore, the relative abundances of Proteobacteria showed a remarkable increase in Si200, which may be the dominant group in sugarcane growth under Si application. Interestingly, the AP was noticed as a major factor that caused bacterial community structure differences between the two Si treatments according to canonical correspondence analysis (CCA). In addition, the association network analysis indicated that Si application enriched the rhizosphere bacterial network, which could be beneficial to sugarcane growth. Overall, appropriate Si application, i.e., 200 kg SiO2 ha−1 promoted sugarcane growth, changed rhizosphere soil enzyme activities and chemical properties, and bacterial community structures.


2020 ◽  
Author(s):  
Zhiyuan Gao ◽  
Yaya Hu ◽  
Meikun Han ◽  
Junjie Xu ◽  
Xue Wang ◽  
...  

Abstract Background: Continuous cropping obstacles from sweet potato are widespread, which seriously reduce the yield and quality, cause certain economic losses. Bacteria of Rhizospheric soil are the richest and are associated with obstacles to continuous cropping. However, few studies on how continuous sweet potato cropping affects the rhizospheric soil bacterial community structure. In the study, Illumina Miseq method was used to explore rhizosphere soil bacterial community structure changes with different sweet potato varieties, and the correlation between soil characteristics and this bacterial community after continuous cropping, to provide theoretical guidance for prevention and treatment of sweet potatoes continuous cropping obstacles. Results: After continuous cropping two years, the results showed that (1) the dominant bacterial phlya in rhizospheric soils from both Xushu18 and Yizi138 were Proteobacteria, Acidobacteria, and Actinobacteria. The most dominant genus was Subgroup 6_norank. The relative abundance of rhizospheric soil bacteria of two sweet potato varieties changed significantly. (2) The richness and diversity indexes of bacteria in Xushu18 rhizospheric soil were higher than those from Yizi138 after continuous cropping. Moreover, the beneficial Lysobacter and Bacillus were more prevalent in Xushu18, but Yizi138 contained more harmful Gemmatimonadetes. (3) Soil pH decreased after continuous cropping, and redundancy analysis result indicated that soil pH was correlated significantly with bacterial community. Spearman’s rank correlations coefficients analysis demonstrated that pH was positively associated with Planctomycetes and Acidobacteria, but negatively associated with Actinobacteria and Firmicutes.Conclusions: After continuous cropping, the bacterial community structure and physicochemical properties of sweet potato rhizospheric soil were unbalanced, and the changes from different sweet potato varieties were different. The contents of Lysobacter and Bacillus were higher in the sweet potato variety resistant to continuous cropping. It provides a basis for developing new microbial fertilizer for sweet potatoes to alleviate continuous cropping obstacle.


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