Agriculture

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351 KiB

Open AccessArticle

Grasslands and Croplands Have Different Microbial Biomass Carbon Levels per Unit of Soil Organic Carbon

by Terence P. McGonigle and William G. Turner

Agriculture 2017, 7(7), 57; https://doi.org/10.3390/agriculture7070057 - 10 Jul 2017

Cited by 19 | Viewed by 8281

Abstract

Primarily using cropped systems, previous studies have reported a positive linear relationship between microbial biomass carbon (MBC) and soil organic carbon (SOC). We conducted a meta-analysis to explore this relationship separately for grasslands and croplands using available literature. Studies were limited to those [...] Read more.

Primarily using cropped systems, previous studies have reported a positive linear relationship between microbial biomass carbon (MBC) and soil organic carbon (SOC). We conducted a meta-analysis to explore this relationship separately for grasslands and croplands using available literature. Studies were limited to those using fumigation–extraction for MBC for field samples. Trials were noted separately where records were distinct in space or time. Grasslands were naturally occurring, restored, or seeded. Cropping systems were typical of the temperate zone. MBC had a positive linear response to increasing SOC that was significant in both grasslands (p < 0.001; r² = 0.76) and croplands (p < 0.001; r² = 0.48). However, MBC increased 2.5-fold more steeply per unit of increasing SOC for grassland soils, as compared to the corresponding response in cropland soils. Expressing MBC as a proportion of SOC across the regression overall, slopes corresponded to 2.7% for grasslands and 1.1% for croplands. The slope of the linear relationship for grasslands was significantly (p = 0.0013) steeper than for croplands. The difference between the two systems is possibly caused by a greater proportion of SOC in grasslands being active rather than passive, relative to that in croplands, with that active fraction promoting the formation of MBC. Full article

(This article belongs to the Special Issue Dynamics of Root–Soil–Microbial Interactions)

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429 KiB

Open AccessArticle

Enhanced Plant Performance in Cicer arietinum L. Due to the Addition of a Combination of Plant Growth-Promoting Bacteria

by María Pérez-Fernández and Valentine Alexander

Agriculture 2017, 7(5), 40; https://doi.org/10.3390/agriculture7050040 - 02 May 2017

Cited by 11 | Viewed by 5411

Abstract

Current agriculture is based on external fertilizers that jeopardize soil fertility. Alternative fertilization systems might come from the use of soil-borne bacteria with plant growth enhancing ability. Here, six bacterial strains that produce varying concentrations of indole acetic acid (IAA) were tested individually [...] Read more.

Current agriculture is based on external fertilizers that jeopardize soil fertility. Alternative fertilization systems might come from the use of soil-borne bacteria with plant growth enhancing ability. Here, six bacterial strains that produce varying concentrations of indole acetic acid (IAA) were tested individually and in consortia for plant growth promotion and fitness-related traits of Cicer arietinum. The nitrogen fixer Mesorhizobium ciceri consistently increased biomass production and N content. In the absence of this strain, IAA Psedomonas putida and Bacillus megaterium hindered plant growth and fitness-related traits. The application of mixes of the three strains always resulted in better plant performance when M. ciceri was present. Mixes that included a P. putida strain that produced low levels of IAA appeared more likely to promote plant growth than mixes that included P. putida strains that produced high levels of IAA or mixes that included B. megaterium. The low levels of IAA produced by the selected strains, compared to the high IAA-producing strains had a significantly greater positive effect on plant biomass accumulation, flower, pod, and seed production, and total plant nitrogen and nitrogen concentrations in seeds. Full article

(This article belongs to the Special Issue Dynamics of Root–Soil–Microbial Interactions)

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Review

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595 KiB

Open AccessReview

Advances in Eco-Efficient Agriculture: The Plant-Soil Mycobiome

by Marcela Claudia Pagano, Eduardo J. Azevedo Correa, Neimar F. Duarte, Bakhytzhan Yelikbayev, Anthonia O’Donovan and Vijai Kumar Gupta

Agriculture 2017, 7(2), 14; https://doi.org/10.3390/agriculture7020014 - 15 Feb 2017

Cited by 24 | Viewed by 10340

Abstract

In order to achieve a desirable ecological and sustainable agriculture a thorough understanding of the plant-soil mycobiome is imperative. Commercial industrial agriculture alters greenhouse gas emissions, promotes loss of plant and soil biodiversity, increases pollution by raising atmospheric CO₂, and releases [...] Read more.

In order to achieve a desirable ecological and sustainable agriculture a thorough understanding of the plant-soil mycobiome is imperative. Commercial industrial agriculture alters greenhouse gas emissions, promotes loss of plant and soil biodiversity, increases pollution by raising atmospheric CO₂, and releases pesticides, thus affecting both terrestrial and aquatic ecosystems. Diversified farming systems, including perennial cultivated pastures, are among worldwide strategies that aim to reduce terrestrial greenhouse gas emissions and deal with threats to global sustainability. Additionally, stimulation of soil microbes and appropriate soil management can influence soil interactions as well as the rates of organic matter decomposition and the release of gases. Agricultural soil microbial communities play a central role in ecosystem processes and are affected by biocontrol agents, biofertilizers, and exposure to pesticides, the extent to which is yet to be fully elucidated. Intercropping different plant species is beneficial, as this can increase carbon fixation by plants, transferring carbon to the soil, especially via mycorrhizas, thus modifying interplant interactions. This review focuses on agro-ecosystems, showing the latest advances in the plant-soil interface (the mycobiome) for an eco-efficient agricultural production. Full article

(This article belongs to the Special Issue Dynamics of Root–Soil–Microbial Interactions)

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