Submitted to: Western Australia No-Till Farmers Association Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: 8/21/2012
Publication Date: 9/4/2012
Citation: Kremer, R.J. 2012. Soil health, plant-microbial interactions and relationships with herbicides. Western Australia No-Till Farmers Association Newsletter. p. 17-18. Interpretive Summary:
Technical Abstract: Soil biological properties critical for successful crop production include microbial diversity and soil carbon content and quality. Soil microbial diversity, or soil biodiversity, may be the most valuable property of any ecosystem because greater diversity provides a greater range of pathways for primary production and ecological processes (i.e., nutrient cycling). Vigorously growing plants contribute to microbial diversity by releasing photosynthetically-fixed carbon through roots (rhizodeposition) to stimulate growth and activity of rhizosphere microorganisms and enhance beneficial relationships including biological nitrogen fixation and mycorrhizal symbioses. Management practices that support a variety of plants and/or incorporation of organic amendments such as manures increase microbial diversity, often reflected in improved nutrient availability and decreased pest pressure. A complete soil management program that maintains availability of both macro- and micronutrients is necessary to sustain physiological activity in plants and soil microorganisms due to their essential roles in enzyme activities that drive all biological processes. Soil organic matter contributes to soil physical and chemical properties by promoting stable aggregation, providing exchange sites for plant nutrients and adsorption of synthetic chemicals. The active carbon fraction of soil organic matter serves as an energy source and substrate for the microbial community to carry out important biological processes. Assessment of soil health, the capacity of soil to function as a vital living system to sustain plant and animal growth and environmental quality, is most appropriate for evaluating the effectiveness and sustainability of soil and crop management systems. Soil health is assessed by measuring soil health indicators, selected on the basis of soil properties, agronomic management goals, and environmental protection. A suite of indicators including aggregate stability, soil organic C fractions, and soil enzyme activities can detect early responses of soil to management practices. Thus, a better understanding of soil health in a crop production system will contribute to estimates of economic and environmental benefits and aid in management decisions for these systems. Results from previous studies on agroecosystems will be presented to illustrate soil health assessment for evaluating management impacts on soil biological function, crop productivity, herbicide interactions with microbial processes and nutrient availability, and environmental quality. Based on results to date, sustainably-managed crops aid in enhancing soil microbial diversity and activity and soil organic matter quality thereby improving soil health, which is essential for sufficient soil and crop productivity and maintenance of environmental quality.