Carbon Sequestration by Tillage, Rotation, and Nitrogen Fertilization in a Mediterranean Vertisol

Abstract

Our objective was to determine the effect of tillage system, crop rotation, and N fertilization on soil organic carbon (SOC) storage in the 0‐ to 90‐cm profile in a long‐term (20‐yr) experiment established in 1986 on a rainfed Mediterranean Vertisol in southern Spain. The treatments studied were: conventional tillage (CT) vs. no‐tillage (NT); five crop rotations: wheat (Triticum aestivum L.)–chickpea (Cicer arietinum L.) (WC), wheat–sunflower (Helianthus annuus L.) (WS), wheat–bare fallow (WF), wheat–faba‐bean (Vicia faba L.) (WFB), and continuous wheat (WW); and N fertilizer applied at four rates (0, 50, 100, and 150 kg N ha−1). The SOC content of soil samples was determined in 1995, 1997, 2000, 2003, and 2006 for four different soil layers (0–15, 15–30, 30–60, and 60–90 cm). The application of N fertilizer did not influence SOC sequestration. The other treatments showed a gradual increase of total SOC content over time, although there were no differences between some consecutive years. The SOC accumulation was higher for 30‐ to 60‐ and 60‐ to 90‐cm depths than other depths due to characteristic cracks of Vertisol. Over the 20 yr of the study, WW and WFB sequestered 21 and 15 Mg C ha−1 more under NT than under CT, respectively. The other crop rotations did not show any difference in C sequestration between NT and CT. Under CT, WS sequestered more SOC than other rotations, while under NT, WW and WFB sequestered more SOC. In general, the crop rotation intensification and NT had a positive effect over time on SOC sequestration in this rainfed Mediterranean Vertisol.

Fertilization increases paddy soil organic carbon density

“…85, 8.18, −0.32, 11.68, 13.01, 16.24, and 18.24 Mg/ha, with average SOC sequestration rates of 0.23, 0.33, −0.01, 0.47, 0.52, 0.65, and 0.73 Mg/(ha·a) in the PK, NP, NK, NPK, 7F:3M, 5F:5M, and 3F:7M treatments, respectively. This was within the range of increase of from <0 to >8 Mg/(ha·a), with an average of 0.33 Mg/(ha·a) found in other studies (Franzluebbers, 2005;West and Six, 2007;López-Bellido et al, 2010).…”

“…et al, 2003;Rasool et al, 2007;Sainju et al, 2008;Pan et al, 2009;Bhattacharyya et al, 2010). The increase in SOC density values ranged from <0 to >8 Mg/(ha·a), with an average of 0.33 Mg/(ha·a) (Franzluebbers, 2005;West and Six, 2007;López-Bellido et al, 2010).…”

“…Compared to no fertilization, some studies suggested that SOC content increases under inorganic fertilization, especially for inorganic nitrogen (N) fertilizers (Majumder et al, 2007;Reid, 2008;Tong et al, 2009;Batlle-Bayer et al, 2010). López-Bellido et al (2010) and Luo et al (2010) suggested that the SOC content does not change, and others suggested that the SOC content decreases (Manna et al, 2006;Khan et al, 2007;Li and Zhang, 2007). Inorganic N fertilizers improve the crop residues in the soil, and thus improve the SOC.…”

Grain legume decline and potential recovery in European agriculture: a review

“…In Mediterranean production systems, reduced tillage with grain legumes has shown especially positive economic effects due to increased water retention that often enhance crop yields (e.g. Lopez-Bellido et al 2010;Sánchez-Girón et al 2004;Soldevilla-Martinez et al 2013). …”

The Impact of Treatment of Organic Manures on Future Soil Carbon Sequestration Under Different Tillage Systems in Pakistan

“…Fertilizer applications can affect SOM content, but reports of impacts are contradictory. Some studies suggest that inorganic N fertilizer increases SOC over unfertilized plots (Batlle-Bayer et al, 2010), whereas others show that SOC either does not change (López-Bellido et al 2010) or decreases with fertilizer application (Li and Zhang, 2007).…”