Convergence of agricultural intensification and climate change in the Midwestern United States: implications for soil and water conservation

Abstract

Abstract. Society faces substantial challenges to expand food production while adapting to climatic changes and ensuring ecosystem services are maintained. A convergence of these issues is occurring in the Midwestern United States, i.e. the 'cornbelt' region that provides substantial grain supplies to world markets but is also well known for its contribution to hypoxic conditions in the Gulf of Mexico due to agricultural nutrient losses. This review examines anticipated trends in climate and possible consequences for grain production and soil resource management in this region. The historic climate of this region has been ideal for large-scale agriculture, and its soils are among the world's most productive. Yet under current trends, degradation of the soil resource threatens our capacity to ensure a stable food supply and a clean environment in the face of a changing climate. A set of strategies and practices can be implemented to meet these challenges by maintaining and improving hydrologic and plant-growth functions of soil, which will improve outcomes for aquatic ecosystems and for the agricultural sector. Soil management ensures our long-term capacity to provide a reliable food supply, and mitigates pressures to expand agricultural practices into marginal croplands that would lead to further environmental degradation.

Weather whiplash in agricultural regions drives deterioration of water quality

“…As weather whiplash increases in this region (Fig. 3), it is likely that land managers will respond to wetter springs by applying more N fertilizer (Hatfield et al 2013). Without future changes in land management, the nascent water quality improvements in the region (Murphy et al 2013) may quickly dissipate due to unforeseen interactions between climate and agriculture.…”

“…Furthermore, climate change will likely result in a stronger weather whiplash with frequent summer droughts coupled to increasingly wet springs (Fig. 3) (Hatfield et al 2013). Increased weather whiplash will bring about increased spring stream nitrate concentrations and associated challenges in managing surface waters for drinking water quality (Fig.…”

“…2b). The 2012 U.S. drought was among the most severe, extensive and costly for the UMRB (Peterson et al 2013), which includes four of the top states for maize and soy production (Illinois, Iowa, Indiana and Missouri), the U.S.'s two most valuable agricultural commodities (Hatfield et al 2013). These four UMRB states contribute 48% of N loading to the Mississippi River (Alexander et al 2008).…”

“…Climate change is predicted to increase the frequency and severity of growing-season drought (Dai 2012;Hatfield et al 2013) and produce more extreme precipitation in the spring (Kunkel et al 1999;Hatfield et al 2013) (defined as [ 30 mm in 24 h). Drought reduces agricultural crop yield (e.g., a 24% reduction of the U.S. maize harvest in 2012, Al-Kaisi et al 2013) and enriches soil nitrate concentrations (Balkcom et al 2003).…”

Impact of weather and climate scenarios on conservation assessment outcomes

“…In addition to annual climate trends, seasonal changes in climate are of particular relevance for crop production systems (Hatfield et al 2013) where agricultural producers themselves become drivers in the rainfall-runoff-erosion system as they adjust crop types, planting dates, and management in response to their perception of climate change (O'Neal et al 2005).…”