Title: Techniques to Enhancing Sustainable Nutrient and Irrigation Management for Potatoes Author
Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 15, 2010
Publication Date: June 1, 2010
Citation: Alva, A.K. 2010. Techniques to Enhancing Sustainable Nutrient and Irrigation Management for Potatoes. Journal of Crop Improvement. 24:281-297. Interpretive Summary: Optimal irrigation management is critical for developing nutrient best management practices aimed to minimize leaching loss of nutrients below the rootzone. Two essential components of optimal irrigation management are: (i) maintaining adequate soil water within the rootzone to avoid/minimize the negative effects of soil water stress on plant growth and production, and (ii) minimize leaching losses of water below the rootzone in an effort to minimize potential contamination of groundwater by agricultural practices and nutrients. The application of capacitance probes have demonstrated a convenient technique for real-time automated soil water content within and below the rootzone. Set points can then be developed as the upper and lower limits of soil water content within the rootzone, so that adequate soil water content is maintained to minimize any negative effects of soil water stress on plant growth and production, while minimizing leaching losses below the rootzone. Furthermore, a potato crop simulation model was validated for the growing conditions in the Northwest. This model can be used as an aid for decision support in order to optimize nutrient uptake and minimize nutrient losses.
Technical Abstract: Two aspects of nutrient and irrigation best management practices (BMP) in relation to sustainable agricultural production systems described in this paper are: (i) application of crop simulation model for decision support system; and (ii) real-time, automated measurement of soil water content to aid in optimal irrigation scheduling aimed to minimize leaching losses below the rootzone. Water transport through the soil profile within and below the crop rootzone plays an important role in determining the nutrient transport, uptake, and possibly leaching below the crop rootzone. Minimizing the latter component is important to avoid wastage of nutrients, thus crop production input, as well as avoiding potential negative impacts on quality of surficial groundwater. Capacitance probes were used in this study for real-time, automated measurement of soil water content at various depths in the soil, i.e. within and below the rootzone. Depth integrated soil water contents were calculated for the rooting depth and below the rooting depth during potato growing season, and evaluated against the irrigation setpoints to monitor: (i) maintaining adequate soil water content within the rootzone to avoid any negative affects of crop water stress; and (ii) fine-tune irrigation scheduling to avoid water leaching into below the rootzone. In team research, a potato crop simulation model was improved by upgrading various model parameters. The upgraded potato simulation model (CSPotato) was integrated with a multi-year, multi-crop simulation model, CROPSYST VB. This enabled to improve overall model capabilities for the assessment of N dynamics, prediction of plant growth, and yield in potato-based cropping systems. In the integrated model, CROPSYST VB simulates the soil-water-plant-atmosphere system for a crop rotation, as well as the water and nitrogen budgets. When the crop in the rotation is potato, CSPotato simulates potato growth and development and plant C and N balances. We have demonstrated that this integrated model successfully predicted plant biomass accumulation, leaf area index, and tuber yield of potato under different nitrogen and irrigation management conditions.