Water Quality Co-Effects of Greenhouse Gas Mitigation in U.S. Agriculture

Abstract

This study develops first-order estimates of water quality co-effects of terrestrial greenhouse gas (GHG) emission offset strategies in U.S. agriculture by linking a national level agricultural sector model (ASMGHG) to a national level water quality model (NWPCAM). The simulated policy scenario considers GHG mitigation incentive payments of $25 and $50 per tonne, carbon equivalent to landowners for reducing emissions or enhancing the sequestration of GHG through agricultural and land-use practices. ASMGHG projects that these GHG price incentives could induce widespread conversion of agricultural to forested lands, along with alteration of tillage practices, crop mix on land remaining in agriculture, and livestock management. This study focuses on changes in cropland use and management. The results indicate that through agricultural cropland about 60 to 70 million tonnes of carbon equivalent (MMTCE) emissions can be mitigated annually in the U.S. These responses also lead to a 2% increase in aggregate national water quality, with substantial variation across regions. Such GHG mitigation activities are found to reduce annual nitrogen loadings into the Gulf of Mexico by up to one half of the reduction goals established by the national Watershed Nutrient Task Force for addressing the hypoxia problem.

Estimating the Impacts of Climate Change and Potential Adaptation Strategies on Cereal Grains in the United States

“…For simplicity, Fisher price and production index numbers were used to capture the multi commodity price and production changes in the nation and the PNW states. We also downscaled the results to the county level for graphic displays utilizing the approach developed in Attwood et al (2000) and Pattanayak et al (2005).…”

Trading Water for Carbon with Biological Carbon Sequestration

“…Afforestation and reforestation in southwestern Australia therefore have the dual environmental benefits of carbon sequestration and increased water use, reducing recharge, lowering water tables, and reversing dryland salinization associated with agriculture (25). Widespread conversion of croplands to forest in the central U.S. farm belt may also improve regional water quality as nutrient, pesticide, and erosion runoff from crop production is reduced (26).…”

An Assessment of Direct on-Farm Energy Use for High Value Grain Crops Grown under Different Farming Practices in Australia

“…Overall, grain growers are increasingly moving from conventional tillage systems to reduced or zero tillage systems because: (1) continuing cultivation systems result in a loss of soil carbon, and about 75% of Australian agricultural lands have less than 1% soil organic carbon [29]. For example, over a 60 year period, cereal cropping soils of Northern New South Wales and Southern Queensland have lost over 40 t C/ha (146.7 t CO 2 e) and 4 t N/ha [30]; (2) the loss of soil carbon adversely affects soil fertility, the soil water holding capacity and plant-available water capacity [31]; and (3) continuous cultivation systems leave soils vulnerable to water and wind erosion, increasing agricultural runoff, degrading soil productivity and releasing GHG by disturbing soils and burning fossil fuels for farm machinery [32,33].…”