The Challenges of Soil Microbial Community Management.

Agricultural practices and philosophies vary widely with regard to the role of microbial communities in crop production systems.  At one end of the spectrum, the emphasis is placed on fertilizer applications to “feed the crop” and soil microbial functions are considered as minor or detrimental to crop nutrient availability.  Microbial functions, especially certain nitrogen transformations, are inhibited due to the reliance on inorganic fertilizers and concerns for nitrogen loss.  On the other end of the spectrum, the emphasis is placed on “feeding the soil” with a primary focus on building soil organic matter.  Microbial functions are considered as key to crop nutrient availability due to a reliance on the decomposition of organic fertilizers.  Neither of these examples really represent microbial community management strategies.  By that, I mean there is no monitoring of different microbial community functions throughout the cropping cycle and there are no specific management practices developed to favor changes in microbial activities to coincide with the crop’s nutritional needs and developmental stages.  The lack of microbial community management strategies for any farming system is due to the substantial challenges in developing such systems.  Determinations must be made on what organisms are involved; what measurements are relevant; how, when and where are these measurements taken; how do they relate to crop growth and health; do they have wide application across different cropping systems and practices; and what are the educational, practical and economic considerations to encourage adoption by producers?  Our symposium speakers were selected to provide an overview of agricultural production systems and discuss microbial community management considerations.  It is our hope and anticipation that you as consultants, researchers, educators and students will be encouraged to further develop microbial management systems into adoptable and adaptable practices to improve the environmental and economic sustainability of agricultural production systems.