7 located in just 9 countries,<sup>9</sup> a fair share of it forested with limited transport infrastructure, and thus not easily accessible, and/or plagued by recurring violence. Africa’s rural population lives highly clustered in more accessible areas with high agricultural potential, in both land abundant and land constrained settings, with limited potential for land expansion (Jayne, Chamberlin and Headey 2014). Over time this will increase pressure for a growing group of smallholders to remain commercially viable and practice sustainable intensification, especially given that the median farm size is declining, in both land abundant and land scarce countries, and given that, beyond a more continuous cultivation of land, agricultural intensification (through use of improved seed, fertilizer, agro-chemicals and water control, as well as mechanization) has remained lower than expected so far in light of population pressures and market access conditions (Binswanger and Savastano 2016).

This challenge is compounded by the generally poor and degrading quality of Africa’s soils. An estimated two-thirds of African land is already degraded, directly affecting about 65 percent of the population (UNECA 2007), a growing body of empirical evidence links low soil fertility to persistent rural poverty (Barrett and Bevis 2015), and poor soils are also less responsive to inorganic fertilizer (Marenya and Barrett 2009, Tittonell and Giller 2013). It also raises the importance of the distribution of especially fertile land and the insecurity of land rights in a number of countries in southern and eastern Africa as well as the imperfect functioning of Africa’s land markets, with the rise of medium and large scale farmers posing additional challenges for smallholder farm expansion (Jayne, Chamberlin and Headey 2014). Together, these constraints limit access to credit, investment in soil fertility and labor mobility (Deininger and Jin 2006; Pender and Fafchamps 2006; Dillon and Voena 2015).

Nonetheless, the best available evidence from SSA still indicates a strong inverse relationship between farm size and crop yields (Barrett, Bellemare and Hou 2010; Carletto, Savastano and Zezza 2013; Larson _et al._ 2014; Bevis and Barrett 2016). While this is not evidence of intrinsic superiority of smaller farms per se—it may well be the endogenous outcome of the various factor market imperfections or behavioral phenomena that generate these patterns<sup>10</sup> --the historical evidence from Asia (Ravallion and Chen, 2007), and more recently also from densely populated African countries such as Ethiopia and Rwanda (World Bank, 2015a,b), shows that increasing smallholder productivity can induce rapid poverty reduction, at least in the initial stages. Studying land rental markets in six African countries, Deininger, Savastano and Xia (2016) also find that, despite significant inefficiencies, land rentals are already occurring, transferring land to land-poor and labor-rich producers. Proper land certification is in some cases also having positive impacts for smallholders, inducing them to maintain soils, make productive investments, and enhance land productivity (Holden _et al._ 2008).

Second, **_<u>water resources</u>_** are sharply limiting in most of the region. The aggregate abundance of water in the equatorial region, from Sierra Leone to Uganda, where countries average between 20 - 100,000 m<sup>3</sup> of renewable freshwater resource per capita per annum, stands in sharp contrast to the 70 percent of SSA countries that receive on average an order of magnitude less (World Bank World Development Indicators). Indeed, FAO data classify 43 percent of the SSA land mass as semi-arid to hyper-arid. Even within the arid states, rain and water resources tend to be concentrated, leaving some subregions particularly arid and hence vulnerable to climate shocks. Climate change poses a serious threat. Western, central and southern Africa may experience a decline in their annual average rainfall by 4 to 5 percent as a direct consequence of climate change (Hoerling et al. 2006). Across SSA an estimated 60 percent of all land is at risk of desertification (Benson et al. 1997).

Improved water and land management can help stem or even reverse those patterns. The most recent household survey data from across the continent show that less than 5 percent of farming households have

> 9 Democratic Republic of Congo, Angola, Congo, Zambia, Cameroon, Mozambique, Central African Republic, Gabon, Sudan.

> 10 Foster and Rosenzweig (2011) suggest that, in India, once one values labor properly, small farms are typically less, not more productive than farms of five or more acres. Some recent cross-country evidence further suggests that policies meant to limit farm sizes may lead to productivity reducing misallocation of land (Adamopoulus and Restuccia 2014).