scholarly journals Short-Term Effects of Cover Grass on Soil Microbial Communities in an Apple Orchard on the Loess Plateau

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1787
Author(s):  
Pan Wan ◽  
Ruirui He

Grass cover may improve soil environmental conditions in apple orchards. However, the mechanisms for how the soil microbial community changes after cover grass treatments are not well understood. In this study, we analyzed soil properties, microbial community diversity and composition in an apple orchard after being covered with native wild grasses for 3 years on the Loess Plateau, China. The ratios of cover grass were 0% (no cover, NC), 20% (low-intensity cover, LIC), 40% (moderate-intensity cover, MIC1), 60% (moderate-intensity cover, MIC2) and 80% (high-intensity cover, HIC). Meanwhile, the relationships between soil nutrients, cover grass properties, and microbial communities was analyzed by redundancy analysis and Pearson correlations. The results showed that cover grass altered the bacterial community composition, and significant changes at the phylum level were mainly caused by Proteobacteria, Bacteroidetes and Chloroflexi. Compared with NC, the abundance of Proteobacteria was lower in LIC, and the abundance of Bacteroidetes was lower in LIC, MIC1 and MIC2, while that of Chloroflexi was higher in LIC. LIC and MIC1 were the only cover grass intensities that altered the soil fungal community composition; there were no significant differences at the phylum level. The changes in the soil microbial community at the given phyla may be related to the change in soil available nitrogen content caused by cover grass. Here, we demonstrate that cover grass changed the soil microbial community, and the changes may be attributed to the given phyla in the bacterial community; soil copiotrophic groups (e.g., Proteobacteria and Bacteroidetes) were found to be at lower abundance in the low-intensity cover grass.

Author(s):  
Pan Wan ◽  
Anzhi Wei

Soil microbiota play an important and diverse roles in horticultural crop nutrition or productivity. However, the soil microbial community composition and the relationships within the taxa in the microbial community populations after cover grass treatments in apple orchards are not well understood. We analysed the microbial community diversity, composition and microbial network of an apple orchard after covering with native wild grasses at different intensities for 2 years in the Loess Plateau, China. The cover grass intensities were 0%, 20%, 40%, 60% and 80%. Soil microbial community diversity was not obviously change by cover grass in the apple orchard. Cover grass altered the microbial bacterial community compositions, their changes exhibited significant differences at the phylum level that were caused by the Proteobacteria, Bacteroidetes, Chloroflexi, Gemmatimonadetes, Nitrospirae. However, low-intensity (20%) and moderate-intensity (40%) treatments were the only cover grass intensities that altered the soil fungal community composition; but their changes did not exhibit significant differences at the phylum level. The positive links among the bacterial taxa decreased with the increasing cover intensity, primarily among Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi and Gemmatimonadetes. Although cover grass increased the positive links between fungal taxa, these taxa were reduced with the increasing cover intensity. Here we demonstrate that cover grass changed the soil microbial community, and the changes may be attributed to the given phyla in the bacterial community; furthermore, the antagonistic effect between the soil bacterial and fungal communities was significantly increased by higher coverage than by lower coverage.


Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 161 ◽  
Author(s):  
Pan Wan ◽  
Gongqiao Zhang ◽  
Zhonghua Zhao ◽  
Yanbo Hu ◽  
Wenzhen Liu ◽  
...  

One of the aims of sustainable forest management is to preserve the diversity and resilience of ecosystems. Unfortunately, changes in the soil microbial communities after forest management remain unclear. We analyzed and compared the soil microbial community of a natural Quercus aliena var. acuteserrata forest after four years of four different management methods using high-throughput sequencing technology. The forest management methods were close-to-nature management (CNFM), structure-based forest management (SBFM), secondary forest comprehensive silviculture (SFCS) and unmanaged control (CK). The results showed that: (1) the soil microbial community diversity indices were not significantly different among the different management methods. (2) The relative abundance of Proteobacteria in the SBFM treatment was lower than in the CK treatment, while the relative abundance of Acidobacteria in the SBFM was significantly higher than that in the CK treatment. The relative abundance of Ascomycota was highest in the CNFM treatment, and that of Basidiomycota was lowest in the CNFM treatment. However, the relative abundance of dominant bacterial and fungal phyla was not significantly different in CK and SFCS. (3) Redundancy analysis (RDA) showed that the soil organic matter (SOM), total nitrogen (TN), and available nitrogen (AN) significantly correlated with the bacterial communities, and the available potassium (AK) was the only soil nutrient, which significantly correlated with the composition of the fungal communities. The short-term SBFM treatment altered microbial bacterial community compositions, which may be attributed to the phyla present (e.g., Proteobacteria and Acidobacteria), and the short-term CNFM treatment altered microbial fungal community compositions, which may be attributed to the phyla present (e.g., Ascomycota and Basidiomycota). Furthermore, soil nutrients could affect the dominant soil microbial communities, and its influence was greater on the bacterial community than on the fungal community.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Maiko Akari ◽  
Yoshitaka Uchida

Livestock waste-based products, such as composted manure, are often used in crop production systems. The products’ microbial characteristics differ depending on animal waste treatment methods used (e.g., biogas production/composting). The question remains whether different livestock waste-based products differently impact soil microbiota. A pot experiment with five treatments (control, chemical fertilizer, digestate + chemical fertilizer, wheat straw compost + chemical fertilizer, and woodchip compost + chemical fertilizer) was conducted to compare the survival rates of microbial communities from digestate and composted manure, after their application to agricultural soil. Potatoes were planted in each pot. The changes in soil pH, the concentration of ammonium and nitrate, and the microbial community properties were monitored after 1, 6, 10, and 14 weeks of the application of livestock waste-based products. The application of composted manure, especially woodchip compost, showed a relatively more extensive impact on the soil microbial community structure than the other treatments. Woodchip compost contained a relatively more abundant and diverse bacterial community than digestate, and its family-level bacterial community structure was similar to that of the soil. These characteristics might determine the extent of the impact of livestock waste-based products on soil microbial communities. Digestate markedly influenced the inorganic nitrogen concentrations in soils but did not affect the soil microbial community. In conclusion, the survival rate of microbes of livestock waste-based products varies depending on the product type. Further investigation is needed to fully understand their impact on soils’ microbial functions.


2021 ◽  
Vol 12 (1) ◽  
pp. 157-172
Author(s):  
Shankar G. Shanmugam ◽  
Normie W. Buehring ◽  
Jon D. Prevost ◽  
William L. Kingery

Our understanding on the effects of tillage intensity on the soil microbial community structure and composition in crop production systems are limited. This study evaluated the soil microbial community composition and diversity under different tillage management systems in an effort to identify management practices that effectively support sustainable agriculture. We report results from a three-year study to determine the effects on changes in soil microbial diversity and composition from four tillage intensity treatments and two residue management treatments in a corn-soybean production system using Illumina high-throughput sequencing of 16S rRNA genes. Soil samples were collected from tillage treatments at locations in the Southern Coastal Plain (Verona, Mississippi, USA) and Southern Mississippi River Alluvium (Stoneville, Mississippi, USA) for soil analysis and bacterial community characterization. Our results indicated that different tillage intensity treatments differentially changed the relative abundances of bacterial phyla. The Mantel test of correlations indicated that differences among bacterial community composition were significantly influenced by tillage regime (rM = 0.39, p ≤ 0.0001). Simpson’s reciprocal diversity index indicated greater bacterial diversity with reduction in tillage intensity for each year and study location. For both study sites, differences in tillage intensity had significant influence on the abundance of Proteobacteria. The shift in the soil bacterial community composition under different tillage systems was strongly correlated to changes in labile carbon pool in the system and how it affected the microbial metabolism. This study indicates that soil management through tillage intensity regime had a profound influence on diversity and composition of soil bacterial communities in a corn-soybean production system.


el–Hayah ◽  
2012 ◽  
Vol 1 (4) ◽  
Author(s):  
Prihastuti Prihastuti

<p>Soils are made up of organic and an organic material. The organic soil component contains all the living creatures in the soil and the dead ones in various stages of decomposition.  Biological activity in soil helps to recycle nutrients, decompose organic matter making nutrient available for plant uptake, stabilize humus, and form soil particles.<br />The extent of the diversity of microbial in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microbial is involved in important soil functions.  That ecologically managed soils have a greater quantity and diversity of soil microbial. The two main drivers of soil microbial community structure, i.e., plant type and soil type, are thought to exert their function in a complex manner. The fact that in some situations the soil and in others the plant type is the key factor determining soil microbial diversity is related to their complexity of the microbial interactions in soil, including interactions between microbial and soil and microbial and plants. <br />The basic premise of organic soil stewardship is that all plant nutrients are present in the soil by maintaining a biologically active soil environment. The diversity of microbial communities has on ecological function and resilience to disturbances in soil ecosystems. Relationships are often observed between the extent of microbial diversity in soil, soil and plant quality and ecosystem sustainability. Agricultural management can be directed toward maximizing the quality of the soil microbial community in terms of disease suppression, if it is possible to shift soil microbial communities.</p><p>Keywords: structure, microbial, implication, sustainable agriculture<br /><br /></p>


Author(s):  
Aiai Xu ◽  
Jie Liu ◽  
Zhiying Guo ◽  
Changkun Wang ◽  
Kai Pan ◽  
...  

It is critical to identify the assembly processes and determinants of soil microbial communities to better predict soil microbial responses to environmental change in arid and semiarid areas. Here, soils from 16 grassland-only, 9 paired grassland and farmland, and 16 farmland-only sites were collected across the central Inner Mongolia Plateau covering a steep environmental gradient. Through analyzing the paired samples, we discovered that land uses had strong effects on soil microbial communities, but weak effects on their assembly processes. For all samples, although no environmental variables were significantly correlated with the net relatedness index (NRI), both the nearest taxon index (NTI) and the β-nearest taxon index (βNTI) were most related to mean annual precipitation (MAP). With the increase of MAP, soil microbial taxa at the tips of the phylogenetic tree were more clustered, and the contribution of determinism increased. Determinism (48.6%), especially variable selection (46.3%), and stochasticity (51.4%) were almost equal in farmland, while stochasticity (75.0%) was dominant in grassland. Additionally, Mantel tests and redundancy analyses (RDA) revealed that the main determinants of soil microbial community structure were MAP in grassland, but mean annual temperature (MAT) in farmland. MAP and MAT were also good predictors of the community composition (the top 200 dominant OTUs) in grassland and farmland, respectively. Collectively, in arid and semiarid areas, soil microbial communities were more sensitive to environmental change in farmland than in grassland, and unlike the major impact of MAP on grassland microbial communities, MAT was the primary driver of farmland microbial communities. Importance As one of the most diverse organisms, soil microbes play indispensable roles in many ecological processes in arid and semiarid areas with limited macrofaunal and plant diversity, yet the mechanisms underpinning soil microbial community are not fully understood. In this study, soil microbial communities were investigated along a 500 km transect covering a steep environmental gradient across farmland and grassland in the areas. The results showed that precipitation was the main factor mediating the assembly processes. Determinism was more influential in farmland, and variable selection of farmland was twice that of grassland. Temperature mainly drove farmland microbial communities, while precipitation mainly affected grassland microbial communities. These findings provide new information about the assembly processes and determinants of soil microbial communities in arid and semiarid areas, consequently improving the predictability of the community dynamics, which have implications for sustaining soil microbial diversity and ecosystem functioning, particularly under global climate change conditions.


1999 ◽  
Vol 89 (10) ◽  
pp. 920-927 ◽  
Author(s):  
Mark Mazzola

Changes in the composition of soil microbial communities and relative disease-suppressive ability of resident microflora in response to apple cultivation were assessed in orchard soils from a site possessing trees established for 1 to 5 years. The fungal community from roots of apple seedlings grown in noncultivated orchard soil was dominated by isolates from genera commonly considered saprophytic. Plant-pathogenic fungi in the genera Phytophthora, Pythium, and Rhizoctonia constituted an increasing proportion of the fungal community isolated from seedling roots with increasing orchard block age. Bacillus megaterium and Burkholderia cepacia dominated the bacterial communities recovered from noncultivated soil and the rhizosphere of apple seedlings grown in orchard soil, respectively. Populations of the two bacteria in their respective habitats declined dramatically with increasing orchard block age. Lesion nematode populations did not differ among soil and root samples from orchard blocks of different ages. Similar changes in microbial communities were observed in response to planting noncultivated orchard soil to five successive cycles of ‘Gala’ apple seedlings. Pasteurization of soil had no effect on apple growth in noncultivated soil but significantly enhanced apple growth in third-year orchard block soil. Seedlings grown in pasteurized soil from the third-year orchard block were equal in size to those grown in noncultivated soil, demonstrating that suppression of plant growth resulted from changes in the composition of the soil microbial community. Rhizoctonia solani anastomosis group 5 (AG 5) had no effect on growth of apple trees in noncultivated soil but significantly reduced the growth of apple trees in soil from third-year orchard soil. Changes in the ability of the resident soil microflora to suppress R. solani AG 5 were associated with reductions in the relative populations of Burkholderia cepacia and Pseudomonas putida in the rhizosphere of apple.


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