# **4. Observed input use and provisioning patterns**

In this section, we investigate input use at various levels – national, regional, household, and plot – as viewed through agro-ecological, market, and demographic lenses. Our choices of disaggregating variables are motivated by patterns reported in the existing literature, by commonly held conceptions about input use, and by the covariates available across surveys. We then investigate some of the joint-input use decisions given known complementarities and a limited set of input provisioning statistics.

# **_4.1. National level input use_**

# <u>Fertilizer</u>

Table 7 describes overall national fertilizer use statistics, including both organic and inorganic fertilizer applications. For inorganic fertilizer, we attempt not only to aggregate total fertilizer use, but also to separate out the main nutrients. In order to extract a nutrient value, in some cases, assumptions are made about the exact type of fertilizer described in the questionnaires (see Appendix 2). Application rates are cleaned on the high end by winsorizing at the 99th percentile. In some countries, we observe unreasonably extreme values in inorganic fertilizer use below the 99th percentile, and therefore apply additional curtailing by replacing total inorganic fertilizer application rates over 700 kg/ha, nitrogen application rates above 200 kg/ha, and phosphorous application rates above 100 kg/ha with those values.<sup>8</sup> For organic fertilizer application rates described in the text, we apply no corrections beyond winsorizing at the 99th percentile.

Subtle differences in how fertilizer application rates were collected may contribute to some differences in observed rates across countries (for more on this issue, see Appendix 2). For example, in Malawi and Tanzania, only up to two types of fertilizer could be reported for a given plot.<sup>9</sup> To the extent that farmers use more than two types, our estimates will therefore be downwardly biased in those two countries. In Nigeria, fertilizer application at the plot level was split into three categories: saved, free, and from commercial sources. In this case, we expect some respondents may have double-counted fertilizer on the same plot where fertilizer was partially free and commercially purchased, leading to over-estimates of actual application rates.

Table 7 shows that around 35 percent of all households in our sample used inorganic fertilizer on their plots in the included main season, with tremendous heterogeneity use across the six countries. Uganda has, by far, the fewest number of inorganic fertilizer users with Malawi at the other extreme. Application rates are high in Malawi and Nigeria, both with government input subsidy programs, and Ethiopia, where the government sets (and subsidizes) fertilizer prices but does not consider it a subsidy program (Rashid et al. 2013). Among fertilizer users, farming households in Tanzania, another country with a government fertilizer subsidy, apply at average rates very similar to Ethiopian households. Of the six countries, the application rates we compile

> 8 This represents an upper-bound limit associated with inorganic fertilizer use in the United States under irrigated corn conditions.

> 9 This is not an issue in Ethiopia where only DAP and UREA are currently available for purchase.

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