<mark>Ethiopia, and around 40 percent in Nigeria use inorganic fertilizer, which may be more widespread than common assumptions about smallholder agriculture posit.</mark> Significant proportions of farmers use agro-chemicals too, with over 30 percent of households in Ethiopia and Nigeria using some on their plots. Other studies using the same data find high rates of chemical use in storage of harvested farm output in the set of eastern and southern African LSMS-ISA countries (Kaminski and Christiaensen 2014), suggesting that the statistics we report represent lower bounds on total chemical use by farmers across agricultural operations. Because the use of pesticides, herbicides, and fungicides is perhaps more widespread than is widely recognized and because chemicals banned in other countries due to their toxicity are being used in SSA (Williamson et al. 2008), this descriptive finding in particular seems to invite further research to explore the prospective environmental and human health effects, as well as the productivity benefits, of non-trivial agro-chemicals use in African agriculture.

# **_2. The incidence of irrigation and mechanization remains quite small._**

While agro-chemical and inorganic fertilizer use appear greater, in some cases, than has been widely acknowledged to date, the prevalence of irrigation and tractor use is negligible, just as the conventional wisdom and macro-level statistics suggest. AQUASTAT/FAO and World Bank estimates report that less than 1 percent of land under cultivation in these countries is irrigated. The household level data we analyze suggest that 1-3 percent of land cultivated by smallholders is under irrigation, and that no more than 10 percent of households have any form of water control on agricultural plots. Of course, because the LSMS-ISA household data do not include large scale commercial farms run as firms rather than as households, these figures are likely somewhat downwardly biased as estimates of overall agricultural production in these countries. But given the modest extent of corporate farming in SSA, the core narrative of minimal levels of irrigation holds up in the most recent data. Tractor ownership is similarly miniscule, as also expressed by FAOSTAT, although actual utilization of tractors and oxen in the countries for which we observe this information (Ethiopia, Niger, Nigeria) is not as insignificant as simple ownership statistics suggest, implying that community level rental or sharing schemes help to facilitate mechanization.

# **_3. Considerable variation exists within countries in the prevalence of input use and of input use intensity conditional on input use._**

Within-country input use patterns vary strikingly, a fact necessarily masked by macro-level statistics of the sort that commonly inform discussions of African agriculture. The LSMS-ISA survey data allow us to disaggregate input use patterns to reveal a great deal of heterogeneity across sub-national regions, agro-ecological zones, and underlying soil types, as well as according to the characteristics of individual households and plots. For example, input use rates vary dramatically within large nations like Ethiopia and Nigeria where, in some regions, less than 10 percent of farmers use inorganic or organic fertilizers while well in excess of 70 percent do so elsewhere in the same country. It remains to be established whether such variation corresponds with differences in the profitability of input use. Analysis of the marginal costs and benefits of using modern inputs – infeasible in the descriptive, cross-sectional work undertaken here – would help determine whether this variation corresponds with efficient allocation of 50