Table 3.

Summary of the external effects associated with seven CSA practices.

	Soil erosion	On-farm biodiversity	Carbon sequestration5	Soil biodiversity	Social impact
Minimum tillage	Strengthen the soil structure which resists soil erosion6,7	Enhances dramatic build-up of soil organism number of different plants per unit area	Increases the concentration of soil organic carbon (SOC) and N within aggregate in the upper 5–8 cm depth	Enhances the fertility of soil through decaying organic matter	No social impact
Improved genetic varieties	Herbicide-tolerant crops do not need tilling thereby less disturbance to the topsoil	There are few or no-toxic effects on non-target organisms in the soil	Improved crop such as the herbicide-tolerant preserve soil and reduces carbon into the atmosphere	Enhances the soil fertility in that the improved crops have a faster degradation and shorter persistence of plant residues	Minimal effect on labour usage
Improved livestock housing	Decreases loss of soil	Trees tend to be harvested thereby reducing plant biodiversity	Overtime produces long-lived nutrient hotspots.	Enhances the fertility of soil through manure derived from kraaling	Has a positive social impact in that it is labour demanding
Mixed cropping	Reduces soil erosion	Enhances the number of different plants per unit area	Enhances the sequestration of soil carbon through using crop residue as mulch	Enhances the fertility of soil through decaying crop residues	Has a positive social impact
Integrated nutrient management	Decreases loss of soil	Enhances the number of different organism per unit area	Enhances the sequestration of soil carbon via using crop residues as mulch	Enhances the fertility of soil through decaying organic matter	Has a positive social impact
Crop rotation	Decreases loss of soil	Increases the number of different plants per unit area	Enhances the sequestration of soil carbon	Enhances the fertility of soil through decaying organic matter	Has a positive social impact
Supplementary feeding	Reduce grazing pressure and therefore ensure ground cover is maintained	has a positive effect in that it supports the re-introduction of crop species	Reduces the GHG emissions	Enhances the fertility of soil through decaying organic matter	Has a positive social impact

Sources: (Bhatt and Khera, 2006; Carpenter, 2011; Claassen, 2013; Duiker and Myers, 2005; Lal, 2004; Lal et al., 2007; Minten et al., 2009; Miura et al., 2008; Orchard et al., 2017; Riginos et al., 2012; Zurbrügg et al., 2010).