Characterizing the release, dynamics and plant availability of phosphorus from recovered struvites

点击翻译按钮获取中文摘要

Current cultivars of crops such as canola require high phosphorus (P) rates to realize their high yield potential. Because of its interaction with soil components, P has very low mobility in most agricultural soils, which necessitates its placement near the zone of root proliferation, i.e., in the seed row, to enhance uptake. However, canola is sensitive to moderately high concentrations of fertilizer nutrients in the soil solution, with the result that placement of high rates of soluble P fertilizers in the seed row can seriously damage or kill seedlings, thereby reducing yield. Placement of seed and all fertilizer in the seed row in one pass is a common practice on the Canadian Prairies; however, for canola, most of that fertilizer has to be placed in a side band or mid-row band to avoid seed damage and seedling mortality. The low mobility of P restricts the accessibility of band-applied P to developing plant roots. Preliminary results from our pot studies suggest that the low solubility, hence low salt index of struvite may allow (i) seed row placement of high P rates without causing seedling toxicity and (ii) application of lower P rates to produce the same yield as higher rates of conventional P fertilizers. Different forms of struvite are increasingly becoming available due to the growing emphasis on replenishing the non-renewable resource (P) and minimizing the adverse environmental impacts of excess P loss to the environment, hence eutrophication of surface water bodies. Despite recent evidence of struvite benefits in crop production, processes and mechanisms controlling struvite P availability in soils and uptake by plants are not well-understood. Such knowledge is needed to formulate strategies for optimizing crop yield and quality and minimizing the build up of excess P in soils, which can be transported to surface water quality and cause eutrophication. My research will employ laboratory, greenhouse, and field techniques to elucidate the processes controlling plant availability and mobility of recovered struvite P in different soils, along with the environmental variables governing the kinetics of P availability. Results will help increase the rates that can be safely applied to meet crop demand and optimize yields without risking seedling toxicity to sensitive crops such as canola. In addition to benefiting farmers, hence Canada's agroeconomy, and minimizing environmental loss of P, thereby protecting Canada's surface water resources, my research program will train HQP in a wide range of research techniques, from modeling P availability, transport and fate processes, as well as state-of-the-art instrumental techniques for characterizing P forms in the soil, to utilization of modeling and analytical results to improve yields in crop fields. My HQP will benefit from interaction with collaborators from the public and private sectors.