Agriculture's Role in Greenhouse Gas Mitigation

Examines technical, economic, and policy trends. Explores efforts to encourage farmers to adopt new agricultural practices that reduce agricultural greenhouse gas emissions. Reviews biofuel options, and related policy implications

CONTRACTING FOR SOIL CARBON CREDITS: DESIGN AND COSTS OF MEASUREMENT AND MONITORING

Many firms anticipate that a cap on greenhouse gas emissions will eventually be imposed, either through an international agreement like the Kyoto protocol or through domestic policy, and have started to take voluntary actions to reduce their emissions. If agricultural producers participate in the emerging market for tradable C-credits, it must be possible to verify that actions farmers take do increase the amount of C in soils and this increase can be maintained over the length of the contract. In this paper we develop a prototype measurement and monitoring scheme for C-credits sequestered in agricultural soils and estimate its costs for the small grain-producing region of Montana using an econometric-process simulation model. Three key results emerge from the prototype framework. First, the efficiency of measurement and monitoring procedures for agricultural soil C sequestration depends on the price of C credits. Second, we find that at all price levels, costs of measuring and monitoring are largest in areas that exhibit the greatest heterogeneity in carbon values. Third, in a case study application of our prototype measurement and monitoring scheme, we find that if we assume similar error and confidence levels as forestry contracts, the upper estimate of measurement and monitoring costs associated with a contract that pays farmers per tonne of C sequestered is 3% of the value of a C-credit. This cost is small relative to the estimated net value of the contract. Thus we conclude that measurement and monitoring costs are not likely to be large enough to prevent producers from participating in a market for tradable credits.Environmental Economics and Policy,

Characterization and expression analysis of Staphylococcus aureus pathogenicity island 3 - Implications for the evolution of staphylococcal pathogenicity islands

We describe the complete sequence of the 15.9-kb staphylococcal pathogenicity island 3 encoding staphylococcal enterotoxin serotypes B, K, and Q. The island, which meets the generally accepted definition of pathogenicity islands, contains 24 open reading frames potentially encoding proteins of more than 50 amino acids, including an apparently functional integrase. The element is bordered by two 17-bp direct repeats identical to those found flanking staphylococcal pathogenicity island 1. The island has extensive regions of homology to previously described pathogenicity islands, particularly staphylococcal pathogenicity islands 1 and bov. The expression of 22 of the 24 open reading frames contained on staphylococcal pathogenicity island 3 was detected either in vitro during growth in a laboratory medium or serum or in vivo in a rabbit model of toxic shock syndrome using DNA microarrays. The effect of oxygen tension on staphylococcal pathogenicity island 3 gene expression was also examined. By comparison with the known staphylococcal pathogenicity islands in the context of gene expression described here, we propose a model of pathogenicity island origin and evolution involving specialized transduction events and addition, deletion, or recombination of pathogenicity island "modules.

ECONOMICS OF AGRICULTURAL SOIL CARBON SEQUESTRATION IN THE NORTHERN PLAINS

Under the Kyoto protocol of the United Nations Framework Convention on Climate Change the United States is charged with reducing emissions of greenhouse gases to seven percent below their 1990 levels by the period 2008-2012. These reductions could be met from many industries including agriculture. In this paper, an economic simulation model is linked to an ecosystem model to quantify the economic efficiency of policies that might be used to sequester carbon (C) in agricultural soils in the Northern Plains region. Simulations with the Century ecosystem model show that long-term soil C levels associated with a crop/fallow system are less than those for grass alone, but that soil C levels for grass-clover-pasture are greater than for continuously cropped grains. The analysis shows that a CRP-style policy is found to be an inefficient means to increase soil C because the per acre payments to convert crop-land to grass-only draw land from both the crop/fallow system and the continuous cropping system, and costs typically exceed $100 per MT (metric ton) of C. In contrast, payments to adopt continuous cropping were found to produce increases in soil C for between$5 to $70 depending on area and degree of targeting of the payments. The most efficient, lowest cost policy is achieved when payments are targeted to land that was previously in a crop/fallow rotation. In this range, soil C sequestration appears to be competitive with C sequestered from other sources.policy design, economic efficiency, soil carbon, sequestration, valuing soil carbon, Great Plains agriculture, Resource /Energy Economics and Policy, Q2,

ECONOMICS OF AGRICULTURAL SOIL CARBON SEQUESTRATION IN THE NORTHERN GREAT PLAINS

Under the Kyoto protocol of the United Nations Framework Convention on Climate Change the United States is charged with reducing emissions of greenhouse gases to seven percent below their 1990 levels by the period 2008-2012. These reductions could be met from many industries including agriculture. In this paper, an economic simulation model is linked to the CENTURY ecosystem model to quantify the economic efficiency of policies that might be used to sequester carbon (C) in agricultural soils in the Northern Great Plains region. Model outputs are combined to assess the costs of inducing changes in equilibrium levels of soil C through three types of policies. The first is a CRP-style policy that provides producers with per-acre payments for converting crop-land to permanent grass; the second is a policy that provides per-acre payments to all farmers that use continuous cropping, regardless of the land's cropping history; the third is a policy that provides per-acre payments for the use of continuous cropping only on land units that had previously been in a crop/fallow rotation. The analysis shows that a CRP-style policy is found to be an inefficient means to increase soil C resulting in costs that typically exceed $100 per MT (metric ton) of C. In contrast, payments to adopt continuous cropping were found to produce increases in soil C for between$5 to $70/MT depending on the geographic area and degree of targeting of the payments. The most efficient, lowest cost policy is achieved when payments are targeted to land that was previously in a crop/fallow rotation. In this range, soil C sequestration appears to be competitive with C sequestered from other sources.policy design, economic efficiency, soil carbon, sequestration, valuing soil carbon, Great Plains agriculture, Environmental Economics and Policy, Q2,

ECONOMICS OF SEQUESTERING CARBON IN THE U.S. AGRICULTURAL SECTOR

Atmospheric concentrations of greenhouse gases can be reduced by withdrawing carbon from the atmosphere and sequestering it in soils and biomass. This report analyzes the performance of alternative incentive designs and payment levels if farmers were paid to adopt land uses and management practices that raise soil carbon levels. At payment levels below $10 per metric ton for permanently sequestered carbon, analysis suggests landowners would find it more cost effective to adopt changes in rotations and tillage practices. At higher payment levels, afforestation dominates sequestration activities, mostly through conversion of pastureland. Across payment levels, the economic potential to sequester carbon is much lower than the technical potential reported in soil science studies. The most cost-effective payment design adjusts payment levels to account both for the length of time farmers are willing to commit to sequestration activities and for net sequestration. A 50-percent cost-share for cropland conversion to forestry or grasslands would increase sequestration at low carbon payment levels but not at high payment levels.Carbon sequestration, greenhouse gas mitigation, afforestation, conservation tillage, no-till, incentive design, leakage, carbon stock, permanence, Environmental Economics and Policy,

Modelling Grass Productivity in the Brazilian Amazon

The Amazon Basin covers an area of 7 million km2, and the central part is almost entirely located within Brazilian territory. This region has the highest rates of deforestation in the world, and the total area deforested now exceeds 600,000 km2. Cattle pasture represents the largest single use (about 70%) of this once-forested land in most of the Brazilian Basin, with an estimated area of 20 million hectares. Our main objective was to simulate grass productivity in different forest to pasture chronosequences within the Brazilian Amazon

Unifying soil organic matter formation and persistence frameworks: the MEMS model

Soil organic matter (SOM) dynamics in ecosystem-scale biogeochemical models have traditionally been simulated as immeasurable fluxes between conceptually defined pools. This greatly limits how empirical data can be used to improve model performance and reduce the uncertainty associated with their predictions of carbon (C) cycling. Recent advances in our understanding of the biogeochemical processes that govern SOM formation and persistence demand a new mathematical model with a structure built around key mechanisms and biogeochemically relevant pools. Here, we present one approach that aims to address this need. Our new model (MEMS v1.0) is developed from the Microbial Efficiency-Matrix Stabilization framework, which emphasizes the importance of linking the chemistry of organic matter inputs with efficiency of microbial processing and ultimately with the soil mineral matrix, when studying SOM formation and stabilization. Building on this framework, MEMS v1.0 is also capable of simulating the concept of C saturation and represents decomposition processes and mechanisms of physico-chemical stabilization to define SOM formation into four primary fractions. After describing the model in detail, we optimize four key parameters identified through a variance-based sensitivity analysis. Optimization employed soil fractionation data from 154 sites with diverse environmental conditions, directly equating mineral-associated organic matter and particulate organic matter fractions with corresponding model pools. Finally, model performance was evaluated using total topsoil (0–20&thinsp;cm) C data from 8192 forest and grassland sites across Europe. Despite the relative simplicity of the model, it was able to accurately capture general trends in soil C stocks across extensive gradients of temperature, precipitation, annual C inputs and soil texture. The novel approach that MEMS v1.0 takes to simulate SOM dynamics has the potential to improve our forecasts of how soils respond to management and environmental perturbation. Ensuring these forecasts are accurate is key to effectively informing policy that can address the sustainability of ecosystem services and help mitigate climate change.</p

Incorporation of crop phenology in Simple Biosphere Model (SiBcrop) to improve land-atmosphere carbon exchanges from croplands

Croplands are man-made ecosystems that have high net primary productivity during the growing season of crops, thus impacting carbon and other exchanges with the atmosphere. These exchanges play a major role in nutrient cycling and climate change related issues. An accurate representation of crop phenology and physiology is important in land-atmosphere carbon models being used to predict these exchanges. To better estimate time-varying exchanges of carbon, water, and energy of croplands using the Simple Biosphere (SiB) model, we developed crop-specific phenology models and coupled them to SiB. The coupled SiB-phenology model (SiBcrop) replaces remotely-sensed NDVI information, on which SiB originally relied for deriving Leaf Area Index (LAI) and the fraction of Photosynthetically Active Radiation (fPAR) for estimating carbon dynamics. The use of the new phenology scheme within SiB substantially improved the prediction of LAI and carbon fluxes for maize, soybean, and wheat crops, as compared with the observed data at several AmeriFlux eddy covariance flux tower sites in the US mid continent region. SiBcrop better predicted the onset and end of the growing season, harvest, interannual variability associated with crop rotation, day time carbon uptake (especially for maize) and day to day variability in carbon exchange. Biomass predicted by SiBcrop had good agreement with the observed biomass at field sites. In the future, we will predict fine resolution regional scale carbon and other exchanges by coupling SiBcrop with RAMS (the Regional Atmospheric Modeling System)