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

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

Consequences of climate change on food-energy-water systems in arid regions without agricultural adaptation, analyzed using FEWCalc and DSSAT

Effects of a changing climate on agricultural system productivity are poorly understood, and likely to be met with as yet undefined agricultural adaptations by farmers and associated business and governmental entities. The continued vitality of agricultural systems depends on economic conditions that support farmers’ livelihoods. Exploring the long-term effects of adaptations requires modeling agricultural and economic conditions to engage stakeholders upon whom the burden of any adaptation will rest. Here, we use a new freeware model FEWCalc (Food-Energy-Water Calculator) to project farm incomes based on climate, crop selection, irrigation practices, water availability, and economic adaptation of adding renewable energy production. Thus, FEWCalc addresses United Nations Global Sustainability Goals No Hunger and Affordable and Clean Energy. Here, future climate scenario impacts on crop production and farm incomes are simulated when current agricultural practices continue so that no agricultural adaptations are enabled. The model Decision Support System for Agrotechnology Transfer (DSSAT) with added arid-region dynamics is used to simulate agricultural dynamics. Demonstrations at a site in the midwest USA with 2008–2017 historical data and two 2018–2098 RCP climate scenarios provide an initial quantification of increased agricultural challenges under climate change, such as reduced crop yields and increased financial losses. Results show how this finding is largely driven by increasing temperatures and changed distribution of precipitation throughout the year. Without effective technological advances and operational and policy changes, the simulations show how rural areas could increasingly depend economically on local renewable energy, while agricultural production from arid regions declines by 50% or more

Relating agriculture, energy, and water decisions to farm incomes and climate projections using two freeware programs, FEWCalc and DSSAT

Context: The larger scale perspective of Integrated Assessment (IA) and smaller scale perspective of Impacts, Adaptation, and Vulnerability (IAV) need to be bridged to design long-term solutions to agricultural problems that threaten agricultural production, rural economic viability, and global food supplies. FEWCalc (Food-Energy-Water Calculator) is a new freeware, agent-based model with the novel ability to project farm incomes based on crop selection, irrigation practices, groundwater availability, renewable energy investment, and historical and projected environmental conditions. FEWCalc is used to analyze the interrelated food, energy, water, and climate systems of Finney County, Kansas to evaluate consequences of choices currently available to farmers and resource managers. Objective: This article aims to evaluate local farmer choices of crops and renewable energy investment in the face of water resource limitations and global climate change. Metrics of the analysis include agricultural and renewable-energy production, farm income, and water availability and quality. The intended audience includes farmers, resource managers, and scientists focusing on food, energy, and water systems. Methods: Data derived from publicly available sources are used to support user-specified FEWCalc input values. DSSAT (Decision Support System for Agrotechnology Transfer) with added arid-region dynamics is used to obtain simulated crop production and irrigation water demand for FEWCalc. Here, FEWCalc is used to simulate agricultural and energy production and farm income based on continuation of recent ranges of crop prices, farm expenses, and crop insurance; continuation of recent renewable-energy economics and government incentives; one of four climate scenarios, including General Circulation Model projections for Representative Concentration Pathway 8.5; and groundwater-supported irrigation and its limitations. Results and Conclusions: A 50-year (2018-2067) climate and groundwater availability projection process indicates possible trends of future crop yield, water utility, and farm income. The simulation during more wet years produces high crop production and slower depletion of groundwater, as expected. However, surprisingly, the simulations suggest that only the Drier Future scenario is commercially profitable, and this is because of reduced expenses for dryland farming. Although simulated income losses due to low crop production are ameliorated by the energy sector income and crop insurance, the simulation under climate change still produces the worst annual total income. Significance: FEWCalc addresses scientific, communication, and educational gaps between global- and local-scale FEW research communities and local stakeholders, affected by food, energy, water systems and their interactions by relating near-term choices to near- and long-term consequences. This analysis is needed to craft a more advantageous future