Search

Abstract: The atmospheric levels of carbon dioxide (CO2) have been due largely to the burning of fossil fuels, deforestation, cultivation of the grasslands, drainage of the land, and land use changes. This has led to increase in greenhouse gases, created concerns about the potential for long-term climate change and interest in developing methods to sequester some of this atmospheric carbon. In agricultural land areas no-tillage (NT) systems have been proposed, to replace moldboard plow and chisel systems as a way to sequester soil organic carbon (SOC). Numerous estimates have been published of soil organic carbon (SOC) sequestration total and rates as a result of a switch to NT systems. Other researchers have proposed the use of cover crops, synthetic fertilizers, organic fertilizer, manure, liming, agricultural systems and management, agroforestry, forages, compost, crop rotations, and reduced row crop use as ways to sequester SOC. For SOC sequestration to occur as a result of a treatment applied to a land unit, all of the SOC sequestered must have come from atmosphere and be transferred into the soil humus through the unit plants, plant residues and other organic solids. The amount of SOC present in the soil humus at the end of the study has to be greater than the pre-treatment SOC levels in the same land unit and there needs to be a net depletion of atmospheric CO2 as a result. The objectives of this paper are to: (1) determine long-term study SOC levels and trends in agricultural lands, (2) application of the SOC sequestration concept to a specific site, (3) identify appropriate experimental designs for plot area use in determining SOC sequestration, (4) develop a procedure, such as pre-treatment measurements of SOC levels in the plots before treatments are applied, to verify SOC sequestration at a site (5) equivalent soil mass sampling method, (6) compare laboratory methods for quantifying SOC content, and (7) account for the loading of C rich amendments. To unequivocally demonstrate SOC sequestration at a specific site has occurred, a temporal increase must be documented relative to pre-treatment SOC level and linked to a net depletion of atmospheric CO2. [Copyright &y& Elsevier]

The present paper studies the land use change impacts of fuels and biofuels. We test the theoretical hypothesis, which says that changes in fuel prices cause changes in land use both directly and indirectly and that, because of price inter-dependencies, biofuels reinforce the land use change impacts. We apply time-series analytical mechanisms to five major traded agricultural commodities, the cultivated area of agricultural land and crude oil price. Our data consists of yearly observations extending from 1950 to 2007 for the US. The empirical findings confirm that markets for crude oil and cultivated agricultural land are interdependent: an increase in oil price by 1dollar/barrel increases land use between 54,000 and 68,000ha. We also find that the increase of bioenergy sector accelerates land use change in the US, i.e. food commodities are being substituted for bioenergy crops. [Copyright &y& Elsevier]

Abstract: This paper develops a forestland management model for the three states in the South Central United States (Arkansas, Louisiana, and Mississippi). Forest type and land-use shares are estimated to be a function of economic and physical variables. The results suggest that while historically pine plantations in this region have been established largely on old agricultural land, in the future pine plantations are likely to occur on converted hardwood-forest lands. This shift in the supply of land for plantations could have large effects on above-ground carbon storage and other ecosystem services. Subsidies of approximately $12–27 per ha per year would maintain the area of hardwood forests and reduce carbon emissions from the above-ground and product pool carbon stocks over the next 30 years. Across the several scenarios considered, results suggest that maintaining hardwoods could be an efficient carbon sequestration alternative. [Copyright &y& Elsevier]