Assessing the impacts of climate change and tillage practices on stream flow, crop and sediment yields from the Mississippi River Basin

Abstract

This study evaluated climate change impacts on stream flow, crop and sediment yields from three different tillage systems (conventional, reduced 1close to conservation, and reduced 2close to no-till), in the Big Sunflower River Watershed (BSRW) in Mississippi. The Soil and Water Assessment Tool (SWAT) model was applied to the BSRW using observed stream flow and crop yields data. The model was calibrated and validated successfully using monthly stream flow data (2001 to 2011). The model performances showed the regression coefficient (R 2) from 0.72 to 0.82 and Nash Sutcliffe Efficiency Index (NSE) from 0.70 to 0.81 for streamflow; R 2 from 0.40 to 0.50 and NSE from 0.72 to 0.86 for corn yields; and R 2 from 0.43 to 0.59 and NSE from 0.48 to 0.57 for soybeans yields. The Long Ashton Research Station Weather Generator (LARS-WG), was used to generate future climate scenarios. The SRES (Special Report on Emissions Scenarios) A1B, A2, and B1 climate change scenarios of the Intergovernmental Panel on Climate Change (IPCC) were simulated for the mid (2046-2065) and late (2080-2099) century. Model outputs showed slight differences among tillage practices for corn and soybean yields. However, model simulated sediment yield results indicated a large difference among the tillage practices from the corn and soybean crop fields. The simulated future average maximum temperature showed as high as 4.8°C increase in the BSRW. Monthly precipitation patterns will remain unchanged based on simulated future climate scenarios except for an increase in the frequency of extreme rainfall events occurring in the watershed. On average, the effect of climate change and tillage practice together did not show notable changes to the future crop yields. The reduced tillage 2

Land cover impacts on storm flow suspended solid and nutrient concentrations in southwest Ohio streams

“…Urbanized watersheds are characterized by high levels of impervious surfaces (Richards et al., ), aging wastewater pipes (Giovannetti, Massey, Haggard, & Morgan, ), and construction sites (Boggs, Sun, McNulty, & Jones, ), all of which can lead to increased stream suspended solid and nutrient concentrations (Halstead, Kliman, Berheide, Chaucer, & Cock‐Esteb, ; Miller, Schoonover, Williard, & Hwang, ; Paul & Meyer, ). Agricultural land in the Midwest is often tilled and coated with fertilizer, which increases runoff containing high concentrations of suspended solids (Parajuli, Jayakody, Sassenrath, & Ouyang, ; Renwick, Vanni, Zhang, & Patton, ) and nutrients (Baker & Laflen, ; Duda, ; King, Fausey, & Williams, ; Sharpley et al., ).…”

The impact of five long-term contrasting tillage systems on maize productivity parameters

“…In the future, gradual climatic changes and unstable meteorological conditions will have a major impact on changes in crop production (Abraha and Savage 2006). Intensive soil tillage may cause soil erosion, which can destroy productive agricultural lands, and climate change can deepen this problem (Parajuli et al 2016). Consequently, one of the most important objectives of future agricultural technologies will be to stabilize soil properties, highly dependent on tillage intensity.…”

“…This result demonstrated the higher potential for maize productivity under unstable meteorological conditions if global warming continues. However, in humid warm climate conditions, the complex effects of climate change and tillage practices have not had a significant influence on crop yields (Parajuli et al 2016).…”

Application of Climate Assessment Tool (CAT) to estimate climate variability impacts on nutrient loading from local watersheds

“…Hydrological processes and surface water quality are vulnerable to climate change through its impact on evapotranspiration, surface runoff, stream flow, water yield, soil erosion, and nutrient loss. Estimate of hydrological processes and surface water quality is central to water resource management, clean water supply, environmental protection, and ecological restoration (Ouyang et al, 2015;Parajuli et al, 2016). To mitigate future climate variability impacts on hydrological processes and water quality, water resource managers and decision makers must be able to assess potential threats and propose practices to adapt the future climatic conditions.…”