scholarly journals Soil properties and agricultural practices shape microbial communities in flooded and rainfed croplands

2020 ◽  
Vol 147 ◽  
pp. 103449 ◽  
Author(s):  
Xiaoyan Wang ◽  
Tianhua He ◽  
Shiying Gen ◽  
Xiao-Qi Zhang ◽  
Xiao Wang ◽  
...  
PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252216
Author(s):  
Laurie Dunn ◽  
Christophe Lang ◽  
Nicolas Marilleau ◽  
Sébastien Terrat ◽  
Luc Biju-Duval ◽  
...  

According to biogeography studies, the abundance and richness of soil microorganisms vary across multiple spatial scales according to soil properties and farming practices. However, soil microorganisms also exhibit poorly understood temporal variations. This study aimed at better understanding how soil microbial communities respond to changes in farming practices at a landscape scale over time. A regular grid of 269 sites was set up across a 1,200 ha farming landscape, and soil samples were characterized for their molecular microbial biomass and bacterial richness at two dates (2011 and 2016). A mapping approach highlighted that spatial microbial patterns were stable over time, while abundance and richness levels were modified. The drivers of these changes were investigated though a PLS-PM (partial least square path-modeling) approach. Soil properties were stable over time, but farming practices changed. Molecular microbial biomass was mainly driven by soil resources, whereas bacterial richness depended on both farming practices and ecological parameters. Previous-crop and management effects and a temporal dependence of the microbial community on the historical farming management were also highlighted.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anthony Horner ◽  
Samuel S. Browett ◽  
Rachael E. Antwis

AbstractModern agricultural practices have vastly increased crop production but negatively affected soil health. As such, there is a call to develop sustainable, ecologically-viable approaches to food production. Mixed-cropping of plant varieties can increase yields, although impacts on plant-associated microbial communities are unclear, despite their critical role in plant health and broader ecosystem function. We investigated how mixed-cropping between two field pea (Pisum sativum L.) varieties (Winfreda and Ambassador) influenced root-associated microbial communities and yield. The two varieties supported significantly different fungal and bacterial communities when grown as mono-crops. Mixed-cropping caused changes in microbial communities but with differences between varieties. Root bacterial communities of Winfreda remained stable in response to mixed-cropping, whereas those of Ambassador became more similar to Winfreda. Conversely, root fungal communities of Ambassador remained stable under mixed-cropping, and those of Winfreda shifted towards the composition of Ambassador. Microbial co-occurrence networks of both varieties were stronger and larger under mixed-cropping, which may improve stability and resilience in agricultural soils. Both varieties produced slightly higher yields under mixed-cropping, although overall Ambassador plants produced higher yields than Winfreda plants. Our results suggest that variety diversification may increase yield and promote microbial interactions.


2020 ◽  
Vol 66 (7) ◽  
pp. 413-433 ◽  
Author(s):  
Micaela Tosi ◽  
Eduardo Kovalski Mitter ◽  
Jonathan Gaiero ◽  
Kari Dunfield

The world’s population is expected to grow to almost 10 billion by 2050, placing unprecedented demands on agriculture and natural resources. The risk in food security is also aggravated by climate change and land degradation, which compromise agricultural productivity. In recent years, our understanding of the role of microbial communities on ecosystem functioning, including plant-associated microbes, has advanced considerably. Yet, translating this knowledge into practical agricultural technologies is challenged by the intrinsic complexity of agroecosystems. Here, we review current strategies for plant microbiome manipulation, classifying them into three main pillars: (i) introducing and engineering microbiomes, (ii) breeding and engineering the host plant, and (iii) selecting agricultural practices that enhance resident soil and plant-associated microbial communities. In each of these areas, we analyze current trends in research, as well as research priorities and future perspectives.


2020 ◽  
Vol 12 (12) ◽  
pp. 4868
Author(s):  
Kun Li ◽  
Guangcai Yin ◽  
Qiuyuan Xu ◽  
Junhua Yan ◽  
Zeng-Yei Hseu ◽  
...  

Biochar is a promising addition for cadmium-contaminated soil in-situ remediation, but its surface properties change after aging, cadmium adsorption is not well-documented, and subsequent environmental effects are still unknown. In this study, wood-derived (Eucalyptus saligna Sm.) biochar was pre-treated to simulate aging and the cadmium sorption process. We then analyzed the resulting physicochemical characteristics. We conducted comparative incubation studies on three age stages of biochar under cadmium adsorption or no cadmium adsorption and then measured soil properties and microbial communities after incubation. Biochar addition raised soil organic carbon (SOC), and aging significantly increased C/N ratios. Aged biochar promoted higher microbial abundance. Aged biochar treatments possessed different microflora with more gram-positive bacteria, significantly altering gram-positive/gram-negative bacteria ratios. Aging significantly increased the oxygen-containing functional groups (OCFGs) and surface area (SA) of biochar. Thus, aged biochar adsorbed more cadmium. Cadmium-binding biochar increased the proportion of gram-negative bacteria and decreased the proportions of gram-positive bacteria and fungi. Similar patterns in phospholipid fatty acids (PLFAs) across adsorption treatments indicated that changes in microbial communities due to the effects of cadmium were confined. The results reveal that biochar aging altered microbial community structure and function more than cadmium binding.


2016 ◽  
Vol 82 (24) ◽  
pp. 7086-7092 ◽  
Author(s):  
Viriya Hantrakun ◽  
Patpong Rongkard ◽  
Malinee Oyuchua ◽  
Premjit Amornchai ◽  
Cherry Lim ◽  
...  

ABSTRACTBurkholderia pseudomalleiis a soil-dwelling bacterium and the cause of melioidosis, which kills an estimated 89,000 people per year worldwide. Agricultural workers are at high risk of infection due to repeated exposure to the bacterium. Little is known about the soil physicochemical properties associated with the presence or absence of the organism. Here, we evaluated the soil physicochemical properties and presence ofB. pseudomalleiin 6,100 soil samples collected from 61 rice fields in Thailand. The presence ofB. pseudomalleiwas negatively associated with the proportion of clay, proportion of moisture, level of salinity, percentage of organic matter, presence of cadmium, and nutrient levels (phosphorus, potassium, calcium, magnesium, and iron). The presence ofB. pseudomalleiwas not associated with the level of soil acidity (P= 0.54). In a multivariable logistic regression model, the presence ofB. pseudomalleiwas negatively associated with the percentage of organic matter (odds ratio [OR], 0.06; 95% confidence interval [CI], 0.01 to 0.47;P= 0.007), level of salinity (OR, 0.06; 95% CI, 0.01 to 0.74;P= 0.03), and percentage of soil moisture (OR, 0.81; 95% CI, 0.66 to 1.00;P= 0.05). Our study suggests thatB. pseudomalleithrives in rice fields that are nutrient depleted. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount ofB. pseudomalleibacteria in affected areas.IMPORTANCEBurkholderia pseudomalleiis an environmental Gram-negative bacillus and the cause of melioidosis. Humans acquire the disease following skin inoculation, inhalation, or ingestion of the bacterium in the environment. The presence ofB. pseudomalleiin soil defines geographic regions where humans and livestock are at risk of melioidosis, yet little is known about the soil properties associated with the presence of the organism. We evaluated the soil properties and presence ofB. pseudomalleiin 61 rice fields in East, Central, and Northeast Thailand. We demonstrated that the organism was more commonly found in soils with lower levels of organic matter and nutrients, including phosphorus, potassium, calcium, magnesium, and iron. We also demonstrated that crop residue burning after harvest, which can reduce soil nutrients, was not uncommon. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount ofB. pseudomalleibacteria in affected areas.


Botany ◽  
2014 ◽  
Vol 92 (4) ◽  
pp. 267-275 ◽  
Author(s):  
Xing-Feng Huang ◽  
Jacqueline M. Chaparro ◽  
Kenneth F. Reardon ◽  
Ruifu Zhang ◽  
Qirong Shen ◽  
...  

The study of the interactions between plants and their microbial communities in the rhizosphere is important for developing sustainable management practices and agricultural products such as biofertilizers and biopesticides. Plant roots release a broad variety of chemical compounds to attract and select microorganisms in the rhizosphere. In turn, these plant-associated microorganisms, via different mechanisms, influence plant health and growth. In this review, we summarize recent progress made in unraveling the interactions between plants and rhizosphere microbes through plant root exudates, focusing on how root exudate compounds mediate rhizospheric interactions both at the plant–microbe and plant–microbiome levels. We also discuss the potential of root exudates for harnessing rhizospheric interactions with microbes that could lead to sustainable agricultural practices.


2018 ◽  
Vol 8 ◽  
Author(s):  
Filipe Behrends Kraemer ◽  
Héctor José María Morrás

Soil macropores are dominant pathways of water flow and their impact on hydraulic properties is directly related to their geometrical and topological characteristics. A number of field and micromorphological analysis have shown that agriculture management under no-tillage promotes the development of a microstructure characterized by platy aggregates and horizontal planes in the topsoil, together with a densification at a subjacent layer, thus raising questions about physical properties and water dynamics under this system of cultivation. Moreover, scarce information is available about the evolution of pore architecture and physical parameters in soils under no-till with different cropping intensity. The objective of this work was to evaluate soil porosity in a silty loam A horizon of a Typic Argiudoll (Monte Buey series) of northern Pampa Region (Argentina) under two no-tilled contrasting managements: Good Agricultural Practices (GAP) –highly intensified cropping sequence including corn and wheat in addition to soybean-, Poor Agricultural Practices (PAP) -simplified crop sequence, with predominance of soybean- and a Natural Environment (NE) as reference. Topsoil porosity was assessed by micromorphology, micromorphometry and water retention curves approach, and the values obtained were related to some physical and chemical variables. Results of the morphological analysis revealed important differences between both agricultural treatments. In the surface layer in GAP, platy aggregates are thick and result from the cohesion of rounded microaggregates of biological origin; in PAP they are thin and dense, resulting mostly from compaction of individual soil particles and small microaggregates. A soil densification is evident in both agricultural treatments at 5-10 cm depth, although the morphology and size of aggregates and pores also differ between them. Micromorphometric analyses have shown differences in total macroporosity as well as in the size, morphology and orientation of macropores between both treatments. Macroporosity values obtained by digital methods were coincidently reflected by the pressure plate method. Porosity variables measured by digital analysis, in particular elongated pores and pore orientation, appear more sensitive than other soil properties (total carbon, aggregate stability, bulk density) in discriminating treatments. Although no-till cultivation led to the formation of platy microstructures and a decrease of soil porosity compared to NE, both agricultural treatments presented optimal values of Ks and water movement was not impaired. As expected, all morphological and analytical soil variables were better in the NE treatment. In addition, it was interesting to verify that the values of several parameters were close or similar between GAP and NE. Even when more intensified crop sequence (GAP) increases machinery traffic, morphological, physical and chemical soil properties were here improved compared to PAP. In this case, the higher proportion of different graminea into the agricultural cycle, besides its effect on the development of root biopores, seems to promote a higher fauna activity which effectively counteracts the vertical mechanical compression produced by traffic. These results suggest that, in addition to the known benefits of non-tillage on soil conservation, the improvement of various soil properties could be achieved by integrating this method of cultivation with suitable agricultural managements.


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