Enhancing Sustainable Nutrient and Irrigation Management for Potatoes

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 at minimizing leaching losses below the root zone. Water transport through the soil profile within and below the crop root zone plays an important role in determining the nutrient transport, uptake, and possibly leaching below the crop root zone. Minimizing leaching losses is important to avoid wastage of nutrients and decrease or prevent nutrient contamination 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 root zone. Depth-integrated soil-water contents were calculated for the rooting depth and below the rooting depth during potato (Solanum tuberosum) growing season, and evaluated against the irrigation setpoints to monitor: (i) adequate soil-water content within the root zone to avoid any negative affects of crop water stress; and (ii) optimal irrigation scheduling to avoid water leaching below the root zone. 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 us 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 – CSPotato), 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.