Efficiency of biochar, nitrogen addition, and microbial agent amendments in remediation of soil properties and microbial community in Qilian Mountains mine soils

Fang

et al. 2022

Forests

Background and Objectives: As an extensively used tree species in landscaping and afforestation in China, lacebark pine (Pinus bungeana Zucc.) seedlings are in high demand. However, the small number of fine roots and the low growth rate of lacebark pine seedlings increase the risks encountered during transplant and extend the nursery time for outplanting. We aimed to find out whether a microbial inoculant would promote root growth and accordingly, shorten the nursery cultivation time. Materials and Methods: One-year-old lacebark pine seedlings were treated with the inoculant Bacillus subtilis 8–32 six times from June to September. At each application time, five treatments of undiluted microbial inoculants (UM), 30 times diluted microbial inoculants (30 DM), 40 times diluted microbial inoculants (40 DM), 50 times diluted microbial inoculants (50 DM), and distilled water as a control (CTRL) were administered to the seedlings. In the end, all the seedlings were harvested to measure the root growth, aboveground growth, and the physiological indices. Results: Root and stem growth was enhanced by the inoculants in terms of the increased number of root tips, the length and surface area of the roots, the biomass of the roots and stems, as well as the increase in height and basal stem diameter. The chlorophyll a/b of the needles was increased, in spite of the fact that the total chlorophyll content was decreased by the microbial inoculant treatments at the end of the growth phase. Meanwhile, the maximum photochemical efficiency (Fv/Fm) of the needles was increased by the inoculant treatments. The soluble sugar content was additionally translocated into the stems in the UM treatment, suggesting the change in carbon allocation. The content of available potassium, phosphorus, and ammonium nitrogen in the potting soil was increased in the 30 DM group, and the content of soil organic matter was increased in all the inoculant treatments. Conclusions: The microbial inoculant Bacillus subtilis 8–32, in appropriate concentrations, could be applied to promote root and shoot growth and improve the seedling quality of the lacebark pine during cultivation.

Section: Discussionsupporting

confidence: 92%

Enhanced Root and Stem Growth and Physiological Changes in Pinus bungeana Zucc. Seedlings by Microbial Inoculant Application

Fang

et al. 2022

Forests

“…Which indicates that biochar application speckled bacterial community composition indirectly through variation in soil properties. A negative correlation between soil pH, MBN and MBC with soil proteobacteria was observed by Kong et al (2021). However, under NPK fertilization, Khan et al (2021) reported a positive correlation of soil proteobacteria with soil N, P and K in sugarcane rhizosphere along with different www.jspae.com (Sun et al, 2021) and after two years in rice field (B) .…”

Section: Relationship Of Soil Proteobacteria With Soil Properties Und...mentioning

confidence: 99%

Response of Soil Proteobacteria to Biochar Amendment in Sustainable Agriculture- A mini review

Zhang

Ullah

Ahmad

et al. 2022

JSPAE

In recent years, biochar application to soil has become more popularized due to its potential roles on soil fertility, plant growth, and development. In this review, we discussed the impact of biochar on the relative abundance of soil proteobacteria and its relationship with soil physiochemical properties under different rhizospheres. It was observed that biochar applied to different soil improved proteobacteria, and its lowest and highest relative abundance was ranged from 30-80%, respectively. A positive relationship of soil proteobacteria with soil pH, total nitrogen, available phosphorous, available potassium, total carbon were observed in several studies. Both the relative abundance of proteobacteria and its relationship with soil properties depend on biochar type, soil type, and fertilizers applied to the soil. Most of the ammonia-oxidizing bacteria including nitrogen-fixing bacteria, ammonia-oxidizing bacteria, cellulose-decomposing bacteria, nitrifying bacteria, and denitrifying bacteria belong to proteobacteria, which plays a significant role in nitrogen recycling that is beneficial for the plant growth, yield and fruits/seeds quality. Furthermore, a positive relationship between soil proteobacteria and plant yield was also highlighted. In this context, the use of biochar plays a potential role to improve the relative abundance of proteobacteria in sustainable agriculture. We highlighted future research guidelines that might benefit the sustainable agricultural system. Moreover, further studies are needed to explore the potential role of biochar application on Proteobaceria families such as Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, and Epsilonproteobacteria.

“…Because biochar is alkaline, its application to the soil can increase soil pH ( Liu, Liu & Zhang, 2014 ). Moreover, the relatively large surface area of biochar addition based on biochar in the short term can improve soil quality by neutralizing soil pH, increasing soil nutrient contents ( Kong et al, 2021 ), and promoting plant growth. In this study, under weakly alkaline soil conditions, adding 3% biochar to the rhizosphere soil of pakchoi resulted in a peak alkaline nitrogen content, a significant increase in soil pH ( Tables 3 and 5 ), and nutrient balance, which was beneficial for the growth and quality improvement of pakchoi.…”

Section: Discussionmentioning

confidence: 99%

“…Biochar amendments can alter plant rhizosphere microbiome, which profoundly affects plant growth and fitness ( Jin et al, 2023 ). Regulation of C/N ratio by adding biochar and N fertilizer affects the composition and diversity of soil bacterial communities ( Kong et al, 2021 ). This study demonstrated that the relative abundance of the bacterial community in pakchoi rhizosphere soil was changed by applying more than 3% biochar.…”

Section: Discussionmentioning

confidence: 99%

Biochar’s role in improving pakchoi quality and microbial community structure in rhizosphere soil

Wu,

Yang,

Zhang

et al. 2024

PeerJ

Background Biochar amendments enhance crop productivity and improve agricultural quality. To date, studies on the correlation between different amounts of biochar in pakchoi (Brassica campestris L.) quality and rhizosphere soil microorganisms are limited, especially in weakly alkaline soils. The experiment was set up to explore the effect of different concentrations of biochar on vegetable quality and the correlation between the index of quality and soil bacterial community structure changes. Methods The soil was treated in the following ways via pot culture: the blank control (CK) without biochar added and with biochar at different concentrations of 1% (T1), 3% (T2), 5% (T3), and 7% (T4). Here, we investigatedthe synergistic effect of biochar on the growth and quality of pakchoi, soil enzymatic activities, and soil nutrients. Microbial communities from pakchoi rhizosphere soil were analyzed by Illumina MiSeq. Results The results revealed that adding 3% biochar significantly increased plant height, root length, and dry weight of pakchoi and increased the contents of soluble sugars, soluble proteins, Vitamin C (VC), cellulose, and reduced nitrate content in pakchoi leaves. Meanwhile, soil enzyme activities and available nutrient content in rhizosphere soil increased. This study demonstrated that the the microbial community structure of bacteria in pakchoi rhizosphere soil was changed by applying more than 3% biochar. Among the relatively abundant dominant phyla, Gemmatimonadetes, Anaerolineae, Deltaproteobacteria and Verrucomicrobiae were reduced, and Alphaproteobacteria, Gammaproteobacteria, Bacteroidia, and Acidimicrobiia relative abundance increased. Furthermore, adding 3% biochar reduced the relative abundance of Gemmatimonas and increased the relative abundances of Ilumatobacter, Luteolibacter, Lysobacter, Arthrobacter, and Mesorhizobium. The nitrate content was positively correlated with the abundance of Gemmatimonadetes, and the nitrate content was significantly negatively correlated with the relative abundance of Ilumatobacter. Carbohydrate transport and metabolism in the rhizosphere soil of pakchoi decreased, and lipid transport and metabolism increased after biochar application. Conclusion Overall, our results indicated that applying biochar improved soil physicochemical states and plant nutrient absorption, and affected the abundance of dominant bacterial groups (e.g., Gemmatimonadetes and Ilumatobacter), these were the main factors to increase pakchoi growth and promote quality of pakchoi. Therefore, considering the growth, quality of pakchoi, and soil environment, the effect of using 3% biochar is better.