Underexplored microbial metabolisms for enhanced nutrient recycling in agricultural soils

Arnab Bhowmik; Mara Cloutier; Emily Ball; Mary Ann Bruns; Arnab Bhowmik; Mara Cloutier; Emily Ball; Mary Ann Bruns

doi:10.3934/microbiol.2017.4.826

AIMS Microbiology

2017, Volume 3, Issue 4: 826-845. doi: 10.3934/microbiol.2017.4.826

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Underexplored microbial metabolisms for enhanced nutrient recycling in agricultural soils

1.
Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, USA
2.
Dual-Title Graduate Program in Biogeochemistry, The Pennsylvania State University, University Park, PA 16802, USA
3.
Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA 16802, USA

Received: 10 July 2017 Accepted: 21 September 2017 Published: 13 October 2017

Worldwide, arable soils have been degraded through erosion and exhaustive cultivation, and substantial proportions of fertilizer nutrients are not taken up by crops. A central challenge in agriculture is to understand how soils and resident microbial communities can be managed to deliver nutrients to crops more efficiently with minimal losses to the environment. Throughout much of the twentieth century, intensive farming has caused substantial loss of organic matter and soil biological function. Today, more farmers recognize the importance of protecting soils and restoring organic matter through reduced tillage, diversified crop rotation, cover cropping, and increased organic amendments. Such management practices are expected to foster soil conditions more similar to those of undisturbed, native plant-soil systems by restoring soil biophysical integrity and re-establishing plant-microbe interactions that retain and recycle nutrients. Soil conditions which could contribute to desirable shifts in microbial metabolic processes include lower redox potentials, more diverse biogeochemical gradients, higher concentrations of labile carbon, and enrichment of carbon dioxide (CO₂) and hydrogen gas (H₂) in soil pores. This paper reviews recent literature on generalized and specific microbial processes that could become more operational once soils are no longer subjected to intensive tillage and organic matter depletion. These processes include heterotrophic assimilation of CO₂; utilization of H₂ as electron donor or reactant; and more diversified nitrogen uptake and dissimilation pathways. Despite knowledge of these processes occurring in laboratory studies, they have received little attention for their potential to affect nutrient and energy flows in soils. This paper explores how soil microbial processes could contribute to in situ nutrient retention, recycling, and crop uptake in agricultural soils managed for improved biological function.
- microbial metabolisms,
- redox potential,
- reduced tillage,
- cover cropping,
- organic amendments,
- efficient biological nutrient cycling,
- greenhouse gas,
- hydrogen consumption,
- atypical nosZ,
- nrfA,
- euknr gene
Citation: Arnab Bhowmik, Mara Cloutier, Emily Ball, Mary Ann Bruns. Underexplored microbial metabolisms for enhanced nutrient recycling in agricultural soils[J]. AIMS Microbiology, 2017, 3(4): 826-845. doi: 10.3934/microbiol.2017.4.826

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Abstract

Worldwide, arable soils have been degraded through erosion and exhaustive cultivation, and substantial proportions of fertilizer nutrients are not taken up by crops. A central challenge in agriculture is to understand how soils and resident microbial communities can be managed to deliver nutrients to crops more efficiently with minimal losses to the environment. Throughout much of the twentieth century, intensive farming has caused substantial loss of organic matter and soil biological function. Today, more farmers recognize the importance of protecting soils and restoring organic matter through reduced tillage, diversified crop rotation, cover cropping, and increased organic amendments. Such management practices are expected to foster soil conditions more similar to those of undisturbed, native plant-soil systems by restoring soil biophysical integrity and re-establishing plant-microbe interactions that retain and recycle nutrients. Soil conditions which could contribute to desirable shifts in microbial metabolic processes include lower redox potentials, more diverse biogeochemical gradients, higher concentrations of labile carbon, and enrichment of carbon dioxide (CO₂) and hydrogen gas (H₂) in soil pores. This paper reviews recent literature on generalized and specific microbial processes that could become more operational once soils are no longer subjected to intensive tillage and organic matter depletion. These processes include heterotrophic assimilation of CO₂; utilization of H₂ as electron donor or reactant; and more diversified nitrogen uptake and dissimilation pathways. Despite knowledge of these processes occurring in laboratory studies, they have received little attention for their potential to affect nutrient and energy flows in soils. This paper explores how soil microbial processes could contribute to in situ nutrient retention, recycling, and crop uptake in agricultural soils managed for improved biological function.

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