Do diverse mixtures of cover crop residues alter the soil microbial community and increase soil function?

2020 ◽  
Author(s):  
Xin Shu ◽  
Yiran Zou ◽  
Liz Shaw ◽  
Lindsay Todman ◽  
Mark Tibbett ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Respiration ◽  
Cover Crops ◽  
Soil Microbial Community ◽  
Cover Crop ◽  
Crop Residues ◽  
Soil Health ◽  
Soil Function ◽  
Soil Microbial ◽  
Quaternary Mixture

<p>Cover crops are a contemporary tool to sustainably manage agricultural soils by boosting fertility, suppressing weeds and disease, and benefiting cash crop yields, thus securing future food supply. Due to the different chemical composition of crop residues from different plant families, we hypothesised that a mixture of cover crop residues may have a greater potential to improve soil health than the sum of the parts. Our experiment focused on the impact of four cover crops (clover, sunflower, radish and buckwheat) and their quaternary mixture on soil respiration and the soil microbial community in an 84-day microcosm experiment. On average adding cover crop residues significantly (P < 0.001) increased soil respiration from 29 to 343 µg C g<sup>-1</sup> h<sup>-1</sup> and microbial biomass from 18 to 60 µg C g<sup>-1</sup>, compared to the unamended control during 84 days’ incubation. Cover crop addition resulted in a significant (P < 0.001) alteration of the soil microbial community structure compared to that of the control. The quaternary mixture of cover crop residues significantly (P = 0.011) increased soil respiration rate by 23.79 µg C g<sup>-1</sup> h<sup>-1</sup> during the period 30 to 84 days after residue incorporation, compared to the average of the four individual residues. However, no significant difference in the size of the microbial biomass was found between the mixture and the average of the four individuals, indicating the mixture may invest resources which transit dormant microbial species into a metabolically active state and thus boost microbial respiration. Analysis of similarity of microbial community composition (ANOSIM) demonstrated the mixture significantly (P = 0.001) shifted microbial community structure away from buckwheat (R = 0.847), clover (R = 0.688), radish (R = 0.285) and sunflower (R = 0.785), respectively. This implies cover crop residues provide a niche specialization and differentiation on a selection of microbial communities that favour certain plant compounds. While applying cover crop residues has positive impacts on soil function, we found that applying a mixture of cover crop residues may provide greater potential to select for microorganisms or activate dormant microbial species which result in higher soil function. The outcome of this study will help seed suppliers to design, and farmers to select, novel cover crop mixtures which enhance soil function synergistically, leading to a greater potential to sustainably improve soil health.</p>

scholarly journals Cover crop residue diversity enhances microbial activity and biomass with additive effects on microbial structure

2021 ◽  
Author(s):  
Xin Shu ◽  
Yiran Zou ◽  
Liz J. Shaw ◽  
Lindsay Todman ◽  
Mark Tibbett ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Respiration ◽  
Microbial Activity ◽  
Cover Crop ◽  
Crop Residue ◽  
Soil Microbial Biomass ◽  
Crop Residues ◽  
Soil Functions ◽  
Soil Microbial

AbstractCover crops have been widely used in agroecosystems to improve soil fertility and environmental sustainability. The decomposition of cover crop residues can have further effects on belowground communities and their activity, which is important for a series of soil functions (e.g., nutrient cycling and organic matter decomposition). We tested the effect of plant residues from a range of cover crop species on soil microbial activity and community assemblage. We predicted that cover crop residues would alter the soil microbial community and that a greater diversity of residues would enhance microbial decomposition. In an incubation study, we assessed the effect of crop residue diversity on microbial activity (soil respiration) and its consequent effects on microbial community composition (PLFA). We used either a biodiverse mixture of four cover crop residues (buckwheat, clover, sunflower and radish) or an equal mass of the residues of each of the individual species. The diverse mixture of cover crop residues had a significantly (P < 0.05) greater soil respiration rate, by 57.61 µg C g−1 h−1, than the average of the four individual residues, but did not have a significantly different soil microbial biomass or microbial community structure. This finding could be attributed to a greater diversity of organic resources increasing the number biochemical niches, and hence activating dormant microbial communities to increase microbial activity without affecting microbial biomass or community composition. Greater respiration from similar microbial biomasses suggests that microbial activity might be more efficient after a more diverse substrate input. This study confirms the positive impact of cover crop residues on soil microbial biomass and activity and highlights that mixtures of cover crop residues may deliver enhanced soil functions beyond the sum of individual cover crop residues.

Influence of Cover Crops on Nitrogen Cycling and the Soil Microbial Community

2021 ◽  
pp. 264-283
Author(s):  
Antonio Castellano-Hinojosa ◽  
Clayton J. Nevins ◽  
Sarah L. Strauss
Keyword(s):  
Microbial Community ◽  
Nitrogen Cycling ◽  
Cover Crops ◽  
Soil Microbial Community ◽  
Soil Microbial

scholarly journals Cover crop-driven shifts in soil microbial communities could modulate tomato early crop growth via plant-soil feedbacks

2021 ◽  
Author(s):  
Micaela Tosi ◽  
John Drummelsmith ◽  
Dasiel Obregón ◽  
Inderjot Chahal ◽  
Laura L. Van Eerd ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Cover Crops ◽  
Cover Crop ◽  
Crop Residues ◽  
Management Strategies ◽  
Soil Microbial Communities ◽  
Crop Productivity ◽  
Residue Management ◽  
Soil Microbial ◽  
Plant Soil

Abstract Sustainable agricultural practices such as crop diversification, cover crops and residue retention are increasingly applied to counteract detrimental effects of agriculture on natural resources. Since part of their effects occur via changes soil microbial communities, it is critical to understand how these respond to different practices. Our study analyzed five cover crop (cc) treatments (oat, rye, radish, rye-radish mixture and no-cc control) and two crop residue management strategies (retention/R+ or removal/R-) in an 8-year diverse horticultural crop rotation trial from ON, Canada. Cc effects were small but stronger than those of residue management. Radish-based cover crops tended to be the most beneficial for both microbial abundance and richness, yet detrimental for fungal evenness. Cc species, in particular radish, also shaped fungal and, to a lesser extent, prokaryotic community composition. Crop residues modulated cc effects on bacterial abundance and fungal evenness (i.e., more sensitive in R- than R+), as well as microbial taxa. Several microbial structure features, some affected by cc, were correlated with early tomato growth in the following spring (e.g., composition, taxa within Actinobacteria, Firmicutes and Ascomycota). Our study suggests that, whereas mid-term cc effects were small, they need to be better understood as they could be influencing crop productivity via plant-soil feedbacks.

scholarly journals The Responses of Soil Microbial to Changed Rainfall and Increased Temperature in Desert Grassland in Northern China

2021 ◽  
Author(s):  
Yi Zhang ◽  
Ying-Zhong Xie ◽  
Hong-Bin Ma ◽  
Juan Zhang ◽  
Le Jing ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Respiration ◽  
Microbial Diversity ◽  
Microbial Communities ◽  
Soil Microbial Community ◽  
Soil Microbial Communities ◽  
Response Strategy ◽  
Desert Grassland ◽  
Soil Microbial Diversity ◽  
Soil Microbial

Abstract Background: The study evaluates how rainfall change and temperature increase affect microbial communities in the desert grassland of Ningxia Autonomous Region, China to explore the soil microbial community and the relationships among the soil microbial community, chemical properties, soil respiration (SR) and plant biomass under the climate change. We established the field experiment with five levels of rainfall by rainout shelters and two levels of temperature by Open-Top Chamber (OTC). Results: The effect of temperature to soil microbial communities is not significant, but with the continuous increase of rainfall, the microbial community gradually increases. Soil microbial diversity negatively correlated with soil CO2 flux. The α-diversity of microbial communities positively correlated with above-living biomass (ALB) and soil temperature (ST), but negatively correlated with root biomass (RB). Conclusions: Both rainfall and temperature’s rising do not promote the soil community α-diversity, but it can promote soil microbial community β-diversity. Soil microbial communities show resistance to rainfall changing. Soil respiration (SR) will limit soil microbial diversity. Soil organic carbon (SOC), soil total nitrogen (STN), and soil total phosphorus (STP) will promote soil microbial abundance and diversity. ALB and ST will promote the soil α-diversity, but the effect of RB to soil microbial is opposite. These findings maybe provide a reliable theoretical basis for formulating a reasonable response strategy in desert steppe ecosystems.

Legacy of constant and diurnally oscillating temperatures on soil respiration and microbial community structure.

2020 ◽  
Author(s):  
Adetunji Alex Adekanmbi ◽  
Yiran Zou ◽  
Xin Shu ◽  
Liz Shaw ◽  
Tom Sizmur
Keyword(s):  
Microbial Community ◽  
Organic Carbon ◽  
Soil Respiration ◽  
Constant Temperature ◽  
Temperature Sensitivity ◽  
Soil Microbial Community ◽  
Incubation Temperature ◽  
Measured Temperature ◽  
Measurement Temperature ◽  
Soil Microbial

&lt;p&gt;Increasing temperatures due to the greenhouse effect are known to increase soil respiration, releasing more CO&lt;sub&gt;2&lt;/sub&gt; into the atmosphere and resulting in a positive feedback in our climate system. Diurnal oscillations in air temperatures influence soil temperatures and thus may affect soil microbial activities and organic carbon vulnerability. Laboratory incubation studies evaluating the temperature sensitivity of soil respiration frequently use measurements of respiration taken at a constant incubation temperature in soil that has also been pre-incubated at a constant temperature. &amp;#160;However, such constant temperature incubations do not represent the field situation, where soils undergo diurnal oscillations in temperate under the influence of changing air temperature. We investigated the effects of constant and diurnally oscillating temperatures on soil respiration, organic matter and soil microbial community composition. A Grassland soil from the UK was either incubated at a constant temperature of 5, 10 or 15 &amp;#186;C , or diurnally oscillated between 5 and 15 &amp;#186;C (increasing or decreasing at 2.5 &amp;#186;C for 3 hour intervals within each 24 hours). Soil CO&lt;sub&gt;2&lt;/sub&gt; flux was measured by temporarily moving incubated soils from each of the abovementioned treatments to 5, 10 or 15 &amp;#186;C, such that soils incubated at each temperature had CO&lt;sub&gt;2&lt;/sub&gt; flux measured at every temperature. Our approach used incubation and measurement temperatures as factors to explore the influence of incubation temperature on the respiration at the measured temperature and to determine temperature sensitivity of CO&lt;sub&gt;2&lt;/sub&gt; flux for each incubation treatment. We hypothesised that a higher measurement temperature would result in greater CO&lt;sub&gt;2&lt;/sub&gt; flux and that, irrespective of measurement temperature, CO&lt;sub&gt;2&lt;/sub&gt; emitted from the 5 to 15 &amp;#186;C oscillating incubation would be similar to that from the 10 &amp;#186;C incubation. The results showed that both incubation and measurement temperatures influence soil respiration differently. Soil respiration measured at 15 &amp;#186;C was greater than that of 5 and 10 &amp;#186;C, irrespective of the incubation temperature. Incubating soil at a temperature oscillating between 5 and 15 oC resulted in greater CO&lt;sub&gt;2&lt;/sub&gt; flux than constant incubations at 10 &amp;#186;C or 5 &amp;#186;C, but was statistically similar to 15 &amp;#186;C. This may be because extracellular depolymerisation is the rate limiting step in soil respiration and the time spent at 15 &amp;#186;C in the oscillating treatment was sufficient to depolymerise enough polysaccharides to maximise intracellular respiration. The greater CO&lt;sub&gt;2&lt;/sub&gt; release in soils incubated at 15 &amp;#186;C or oscillating between 5 and 15 &amp;#186;C coincided with depletion of the soil organic carbon and a shift in the phospholipid fatty acid profile of the soil microbial community, consistent with thermal adaptation to higher temperatures. Dissolved organic carbon and C/N ratio significantly decreased in soils incubated at 15 &amp;#186;C or oscillating between 5 and 15 &amp;#186;C with attendant increase in the ratios of Gram negative to positive bacteria and cis/trans ratio, and decreased Fungi/Bacteria ratio. Our results suggest that daily maximum temperatures are more important than daily minimum or average temperatures when considering the response of soils to warming.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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