Creating Carbon Offsets in Agriculture through No-Till Cultivation: A Meta-Analysis of Costs and Carbon Benefits

Abstract

Abstract. Carbon terrestrial sinks are often seen as a low-cost alternative to fuel switching and reduced fossil fuel use for lowering atmospheric CO 2 . To determine whether this is true for agriculture, one meta-regression analysis (52 studies, 536 observations) examines the costs of switching from conventional tillage to no-till, while another (51 studies, 374 observations) compares carbon accumulation under the two practices. Costs per ton of carbon uptake are determined by combining the two results. The viability of agricultural carbon sinks is found to vary by region and crop, with no-till representing a low-cost option in some regions (costs of less than $10 per tC), but a high-cost option in others (costs of 100-$400 per tC). A particularly important finding is that no-till cultivation may store no carbon at all if measurements are taken at sufficient depth. In some circumstances no-till cultivation may yield a "triple dividend" of carbon storage, increased returns and reduced soil erosion, but in many others creating carbon offset credits in agricultural soils is not cost effective because reduced tillage practices store little or no carbon.

Industry perspectives on carbon-offset programs in Canada and the United States

“…Cost is not necessarily easy to calculate. Meta-analyses of cost estimates of carbonoffset projects show that calculations can vary by more than an order of magnitude, depending on the factors considered for the calculation (van Kooten et al 2004;Manley et al 2005).…”

Farmers’ Perceptions and Factors Influencing the Adoption of No-Till Conservation Agriculture by Small-Scale Farmers in Zashuke, KwaZulu-Natal Province

“…Some research and development organizations now view the technology as one of the solutions to the adverse effects of climate change [1]. Although the role of no-till as a climate-smart solution is being questioned [1][2][3], the technology still remains one of the solutions to address some of the challenges affecting small-scale farming in Africa [1]. Amongst the major challenges faced by small-scale farmers are soil erosion and the efficiency in which the limited water is used [4][5][6].…”

Biological carbon sequestration and carbon trading re-visited

“…Farmers who adopt zero tillage balance costs (lower yields, higher chemical outlays) against benefits (labor and machinery savings Adapted from Manley et al (2005) due to reduced field operations, and carbon payments if any). Low output and chemical input prices during the 1990s meant that the gain to no-till offsets the financial loss due to lower yields and greater use of chemicals to control weeds.…”

“…As prices and technologies change (e.g., due to incentives promoting biofuels), soil conservation practices could be reversed, thereby releasing carbon stored in soils. It is also not uniformly true that zero tillage sequesters more carbon than conventional tillage (Baker et al 2007;Manley et al 2005), which would lead to extremely (even infinitely) high costs of creating carbon credits. Some cost estimates based on meta-analyses of 52 studies of soil carbon flux and 51 studies of cost differences between conventional and zero tillage are provided in Table 2.…”