OPTIMIZING WATER USE EFFICENCY IN HIGH VALUE CROPS

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My research program aims to develop water management systems, that increase crop productivity under limited water supplies, reduce contamination of water resources, and mitigate greenhouse gas emissions. Our findings, over the past six years, have indicated crop reflectance indices most sensitive for detecting water stress in high value vegetable crops in the greenhouse and field. The results were scaled up to larger fields, using Unmanned Aerial Vehicles equipped with multispectral and thermal cameras. However, this was costly, time consuming, highly weather dependant, and difficult to accurately assess crop water stress due to the high spatial heterogeneity of soil and crop parameters. To overcome these limitations, we will take advantage of most recent developments in satellite technology and numerically powerful energy balance algorithms, to precisely estimate crop evapotranspiration (ETc) and crop water stress (CWS) over large irrigated regions. New Nano-satellites can provide crop reflectance data at very high resolution, thrice daily. This enables irrigation applications on a near real-time basis, and is an unprecedented development in satellite mapping of ETc. Furthermore, when ETc and CWS are coupled with soil moisture derived from NASA's SMAP platform, this will yield another unprecedented innovation using both crop and soil parameters to estimate irrigation applications, making for more precise and robust irrigation scheduling. We will test these innovations in large, irrigated vegetable producing regions of Southern Quebec and Ontario, using our recently developed algorithms to delineate irrigation management zones (field blocks with nearly similar soil properties and topography), thus accounting for spatial heterogeneity in large fields. By integrating the power of both geospatial and crop growth modelling, we will determine the most optimum irrigation water applications in each management zone, to maximize crop yields. This is also an unprecedented innovation in crop water productivity modelling and assessment that has hitherto not been explored. The potential for additional water savings through buried drip and regulated deficit irrigation will be investigated using the HYDRUS model. Anticipated outcomes are: advanced techniques for measuring crop water stress and soil moisture using recent innovations in satellite monitoring; algorithms to support site-specific irrigation management at regional scales, and; irrigation management practices which maximize crop yields while simultaneously conserving scarce water resources. The research benefits, which are of global importance, include a more economically competitive vegetable production sector, higher water use efficiency in agriculture, conservation of limited water supplies, and new remotely sensed products for soil and water management. The results will be highly beneficial to irrigation advisors and water resource planners in the federal and provincial governments.