Three essays on water management strategies in response to climate change

Abstract

Due to climate change, the amount of rainfall, and its uneven temporal and spatial distribution, affect water availability. As a result, both households and farmers need to adapt to climate change by taking appropriate actions. This dissertation incorporates insights from scholarship on both adaptation to climate change and innovation adoption. For residents, adopting drought tolerant plants (DTPs) to conserve water use is a potential adaptation to the predicted effects of climate change. Survey responses from 624 households in Missouri are analyzed using a univariate probit model. DTPs adoption is positively correlated with both low and high household incomes, homeownership, living in rural subdivisions, mowing lawns high, time spent on yardwork, pro-environmental attitudes, and concerns about droughts. Policy interventions might include subsidizing the purchase of DTPs, requirements for use of DTPs in new housing developments, and targeted educational efforts. To encourage farmers to conserve water and use water more efficiently, understanding their decision-making on adoption of enhanced irrigation systems and scientific scheduling practices is essential. Using data from the national 2013 Farm and Ranch Irrigation Survey (FRIS) conducted by USDA, this dissertation employs a mixed and multilevel approach to analyze both land- and crop-specific irrigation decisions. Three land-level equations on irrigation share, irrigation application rate, and harvest share are estimated. Results show that irrigation share, application rate and harvest share are associated with variables related to water costs, farm size, irrigation systems, barriers to improvements, information sources, etc. In addition, the adoption decisions are analyzed focusing on corn and soybean farms using multilevel models (MLMs) as they can better deal with the farm-level data embedded in states. Application of MLMs to the analysis of farmers' adoption provides new insights on the proportion of variability in each response accounted for by farm- versus state-level factors. The results suggest that, while adoption is affected by land areas, off-farm surface water, various barriers and information sources, the variability of pressure irrigation adoption is mainly accounted for by factors at the state level, while the adoption of scientific scheduling practices is mainly accounted for by farm-level variation. Controlling for farm-level factors, farmers in areas with drought conditions in 2012, i.e., lower than average rainfall and higher than average temperatures, are more likely to have adopted pressure irrigation systems and scientific scheduling practices by 2013. In addition, sustainability of water resources requires producers to take account of marginal user costs when making production decisions. Adoption of enhanced irrigation systems and higher water cost can achieve potential improvements in irrigation water use efficiency. In a multicrop production system with irrigation, farmers make decisions about land allocated to each crop, irrigation water application, and their decisions, along with growing conditions, determine crop supply. This dissertation also analyses water application to multiple crops at the farm level and the effects of influential factors on irrigation water use efficiency of specific crops. As MLMs permit the incorporation of state-level variables, they are further applied in analyzing the multicrop production decisions and irrigation water use efficiency. The results show higher water price encourages efficient water use. Moreover, adoption of pressure irrigation systems could reduce soybean water use or increase corn yield. Adoption of pressure irrigation increases the economic irrigation water use efficiency on soybean farms. The findings from MLMs show that variables representing deviations from 30 year state average climate conditions in 2012 and 2013 have fairly consistent effects. Climate risks and higher temperatures promote more efficient water use and higher yields. Higher precipitation is correlated with lower water application and higher crop yield. Federal programs and policy should not only target specific barriers and increase the effectiveness of incentives at the farm level, but also address differing priorities in each state. Implications from these analyses should benefit future policy design and improve education programs.