Editing IPCC:AR6/SRCCL/Chapter-5 (section)

==== 5.6.4.3 Conservation agriculture ====

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Conservation agriculture (CA) is based on the principles of minimum soil disturbance and permanent soil cover, combined with appropriate crop rotation (Jat et al. 2014 <sup>[[#fn:r1115|1115]]</sup> ; FAO 2011e <sup>[[#fn:r1116|1116]]</sup> ). CA has been shown to respond with positive benefits to smallholder farmers under both economic and environmental pressures (Sapkota et al. 2017a, 2015 <sup>[[#fn:r1117|1117]]</sup> ). This agricultural production system uses a body of soil and residues management practices that control erosion (Blanco Sepúlveda <sup>[[#fn:r1118|1118]]</sup> and Aguilar Carrillo 2016) and at the same time improve soil quality, by increasing organic matter content and improving porosity, structural stability, infiltration and water retention (Sapkota et al. 2017a, 2015 <sup>[[#fn:r1119|1119]]</sup> and Govaerts et al. 2009).

Intensive agriculture during the second half of the 20th century led to soil degradation and loss of natural resources and contributed to climate change. Sustainable soil management practices can address both food security and climate change challenges faced by these agricultural systems. For example, sequestration of soil organic carbon (SOC) is an important strategy to improve soil quality and to mitigation of climate change (Lal 2004 <sup>[[#fn:r1120|1120]]</sup> ). CA has been reported to increase farm productivity by reducing costs of production (Aryal et al. 2015 <sup>[[#fn:r1121|1121]]</sup> ; Sapkota et al. 2015 <sup>[[#fn:r1122|1122]]</sup> ; Indoria et al. 2017 <sup>[[#fn:r1123|1123]]</sup> ) as well as to reduce GHG emission (Pratibha et al. 2016 <sup>[[#fn:r1124|1124]]</sup> ).

Conservation agriculture brings favourable changes in soil properties that affect the delivery of nature’s contribution to people (NCPs) or ecosystem services, including climate regulation through carbon sequestration and GHG emissions (Palm et al. 2013 <sup>[[#fn:r1125|1125]]</sup> ; Sapkota et al. 2017a <sup>[[#fn:r1126|1126]]</sup> ). However, by analysing datasets for soil carbon in the tropics, Powlson et al. (2014, 2016) argued that the rate of SOC increase and resulting GHG mitigation in CA systems, from zero-tillage in particular, has been overstated (Chapter 2).

However, there is unanimous agreement that the gain in SOC and its contribution to GHG mitigation by CA in any given soil is largely determined by the quantity of organic matter returned to the soil (Giller et al. 2009 <sup>[[#fn:r1127|1127]]</sup> ; Virto et al. 2011 <sup>[[#fn:r1128|1128]]</sup> ; Sapkota et al. 2017b <sup>[[#fn:r1129|1129]]</sup> ). Thus, a careful analysis of the production system is necessary to minimise the trade-offs among the multiple use of residues, especially where residues remain an integral part of livestock feeding (Sapkota et al. 2017b <sup>[[#fn:r1130|1130]]</sup> ). Similarly, replacing mono-cropping systems with more diversified cropping systems and agroforestry, as well as afforestation and deforestation, can buffer temperatures as well as increase carbon storage (Mbow et al. 2014a <sup>[[#fn:r1131|1131]]</sup> ; Bioversity International 2016 <sup>[[#fn:r1132|1132]]</sup> ), and provide diversified and healthy diets in the face of climate change.

Adoption of conservation agriculture in Africa has been low despite more than three decades of implementation (Giller et al. 2009 <sup>[[#fn:r1133|1133]]</sup> ), although there is promising uptake recently in east and southern Africa. This calls for a better understanding of the social and institutional aspects around CA adoption. Brown et al. (2017a) <sup>[[#fn:r1134|1134]]</sup> found that institutional and community constraints hampered the use of financial, physical, human and informational resources to implement CA programmes.

Gender plays an important role at the intra-household level in regard to decision-making and distributing benefits. Conservation agriculture interventions have implications for labour requirements, labour allocation, and investment decisions, all of which impact the roles of men and women (Farnworth et al. 2016 <sup>[[#fn:r1135|1135]]</sup> ) (Section 5.1.3). For example, in the Global South, CA generally reduces labour and production costs and generally leads to increased returns to family labour (Aryal et al. 2015 <sup>[[#fn:r1136|1136]]</sup> ) although a gender shift of the labour burden to women have also been described (Giller et al. 2009 <sup>[[#fn:r1137|1137]]</sup> ).

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