No-tillage lessens soil CO<sub>2</sub> emissions the most under arid and sandy soil conditions: results from a meta-analysis

Abstract

Abstract. The management of agroecosystems plays a crucial role in the global carbon cycle with soil tillage leading to known organic carbon redistributions within soils and changes in soil CO 2 emissions. Yet, discrepancies exist on the impact of tillage on soil CO 2 emissions and on the main soil and environmental controls. A meta-analysis was conducted using 46 peer-reviewed publications totaling 174 paired observations comparing CO 2 emissions over entire seasons or years from tilled and untilled soils across different climates, crop types and soil conditions with the objective of quantifying tillage impact on CO 2 emissions and assessing the main controls. On average, tilled soils emitted 21 % more CO 2 than untilled soils, which corresponded to a significant difference at P <0.05. The difference increased to 29 % in sandy soils from arid climates with low soil organic carbon content (SOC C < 1 %) and low soil moisture, but tillage had no impact on CO 2 fluxes in clayey soils with high background SOC C (> 3 %). Finally, nitrogen fertilization and crop residue management had little effect on the CO 2 responses of soils to no-tillage. These results suggest no-tillage is an effective mitigation measure of carbon dioxide losses from dry land soils. They emphasize the importance of including information on soil factors such as texture, aggregate stability and organic carbon content in global models of the carbon cycle.

Responses of soil carbon sequestration to climate‐smart agriculture practices: A meta‐analysis

“…Conservation tillage merely reduces soil disturbance and normally does not add extra materials to soils. For example, NT increased SOC by 7% in the 0-3 cm soil layer (Abdalla et al, 2016) and by 3% at the 40 cm depth . Biochar is a carbon-rich material with a charged surface, organic functional groups, and a porous structure, which can potentially increase soil aggregation and cation exchange capacity (Jien & Wang, 2013).…”

“…Although these CSA management practices have been widely used to enhance soil health (e.g., Denef, Zotarelli, Boddey, & Six, 2007;Fungo et al, 2017;Thomsen & Christensen, 2004;Weng et al, 2017), their effects on SOC sequestration are variable and highly dependent on experiment designs and site-specific conditions such as climate and soil properties (Abdalla, Chivenge, Ciais, & Chaplot, 2016;Liu et al, 2016;Paustian et al, 2016;Poeplau & Don, 2015). The potential to sequester soil carbon varies greatly among CSA practices, which has not been well addressed.…”

“…The potential to sequester soil carbon varies greatly among CSA practices, which has not been well addressed. Also, most prior quantitative research focused on the effects of a single CSA practice on SOC (e.g., Abdalla et al, 2016;Liu et al, 2016;Poeplau & Don, 2015), very few studies estimated the combined effects of diverse CSA and conventional management practices. Also, most prior quantitative research focused on the effects of a single CSA practice on SOC (e.g., Abdalla et al, 2016;Liu et al, 2016;Poeplau & Don, 2015), very few studies estimated the combined effects of diverse CSA and conventional management practices.…”

Sustainable production of sweet sorghum for biofuel production through conservation agriculture in South Africa

“…Unlike N 2 O, CA, RT, and NT reduced CO 2 emissions from the soil compared with CT (Abdalla et al, 2013(Abdalla et al, , 2016Chatskikh et al, 2008;Jia et al, 2016). Abdalla et al (2016) using a meta-analysis study reported that NT treatments had 21% less CO 2 emissions compared with CT treatments. Jia et al (2016) found that CO 2 emissions were higher by about 7.8% under CT treatment using moldboard plow than under NT.…”

“…Extensive research on soil GHG has hitherto focused on tillage practice and fertilization (Abdalla, Chivenge, Ciais, & Chaplot, 2016;Bauer, Frederick, Novak, & Hunt, 2006;Jia et al, 2016;Six et al, 2004;Ussiri & Lal, 2009), but GHG emissions involves a complex interaction of many factors. According to Bilandžija, Zgorelec, and Kisić (2016), focusing on one or two factors may lead to different results across studies.…”