Nutrient Dynamics: Utilizing Biotic-Abiotic Interactions for Improved Management of Agricultural Soils

摘要

Environmental concerns currently trigger the development of more sustainable soil fertility management strategies. It appears that effective sustainable practices are those that enhance natural soil processes, Soil processes include the decompositionof residues and mineralization of organic matter, nitrogen fixation, nitrification, nitrate leaching, denitrification and sulfur reduction. Natural soil processes also include less well-understood interactions, namely, those leading to the dissolution ofminerals by organic acids, as well as rhizospheric and mycorrhizospheric interactions. Plants, associated with aibusculai mycor- ihizal symbionts, supply and distribute carbon and energy, sustaining most of the biotic mechanisms responsible for nutrientrelease from soil, and maintaining organic pools of nutrients. Among these pools, the mi-crobial biomass and fine loots pools, with their very fast tumovei time, are particularly important as they can maintain large amounts of nutrients in very labile form and, therefore, increase soil fertility. Agricultural soil systems are very dynamic and are characterized by large spatial and temporal variations, which are largely driven by plant development. In addition, nutrient dynamics in agricultural soil systems seem particularly influenced fay temperature, moisture, and nitrogen and phosphorus fertilization. Nitrogen losses from soil are reduced in systems where nitrogen release corresponds to plant demand Biological nitrogen fixation is a sound way to input nitrogen in cropping systems Phosphorus losses can be reduced through increased reliance on the arbuscular mycorrhizal symbiosis of crops. Soils are diverse and complex systems, which, furthermore, respond to increasingly unpredictable climatic variations. Optimal agricultural soil management is a moving target and, hence, a challenging goal that will never be totally reached.