Simulating and Analyzing Use of Water and Renewable Energy in Agricultural Areas Using FEWCalc and DSSAT

Abstract

As much of farmland in the middle USA is located in arid and semi-arid regions, agricultural practices depend primarily on irrigation. Widely prevalent large-scale groundwater extraction for agriculture began in the 1950s with the introduction of center pivot irrigation, each of which requires about 800 gallons/min, or 4,360 m3/day. Groundwater supported irrigation was dependable for decades, but now many areas of the High Plains aquifer is at risk for over-extraction, and farming is facing difficult circumstances. On the positive side, Kansas recently became the fifth leading producer of wind energy, with solar power production growing in recent years. However, opportunities to use this locally produced energy to improve prospects for the farming community face scientific and engineering challenges and, communities are not aware of many potentially promising alternatives. Food-Energy-Water Calculator (FEWCalc) is a freeware interactive computer program designed to inform farmers about economic and water resource consequences of land-use alternatives in the face of climate variability and long-term change. FEWCalc integrates the agricultural model, Decision Support System for Agrotechnology Transfer (DSSAT), and Agent-Based Modeling (ABM), and is novel in its attention to farm economy, groundwater quantity and surface water quality, and its ability to realistically account for arid climates. FEWCalc is demonstrated and tested using data from Garden City, Kansas, USA. It allows users to define model parameters such as the acreage planted in four crops (corn, wheat, soybeans, and grain sorghum); the number of solar panels and wind turbines, and their financial variabilities; and one of four 50-year projected scenarios. FEWCalc results show high variability of net farm income due to price uncertainty and weather conditions. FEWCalc outputs also present how water supplies threaten farm incomes and indicate that renewable energy development has the potential to support farm systems and provides economic opportunities to balance farming difficulties. Results from Scenario 1 (Repeat Historical) are repeated based on conditions from a 10-year base period (2008-2017) in sequence. For Scenario 2 (Wetter Future), FEWCalc can maintain irrigation operations for the entire 60-year simulation. Scenario 3 (Drier Future) resorts to dryland farming more quickly than other scenarios, but it produces the highest average annual net income. Scenario 4 (Climate Change) indicates increased challenges such as reduced crop yields and increased financial losses under climate change. This finding addresses the challenges of the future and provides a tool for research and education. The existing human interaction capabilities of FEWCalc would be improved by adding human decision-making characteristics such as avoidance of risk, maximizing profit, and evolution of policies and governmental institutions.