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Michigan State University (2012)

Maize Production in Zambia and Regional Marketing : Input Productivity and Output Price Transmission

Burke, William

Titre : Maize Production in Zambia and Regional Marketing : Input Productivity and Output Price Transmission.

Auteur : Burke, William

Université de soutenance : Michigan State University (MSU)

Grade : DOCTOR OF PHILOSOPHY 2012

Résumé
Chapter 1 is an analysis of the determinants of maize yield response to fertilizer applications using longitudinal data collected in 2004 and 2008 from 7,127 smallholder maize fields. The Instrumented Pooled Correlated Random Effects estimator is employed to control for several statistical considerations often overlooked in the social science literature on smallholder production. The model is specified such that response rates to fertilizer application are conditional on certain farmer practices and the agro-ecological conditions under which maize is grown. Findings indicate top dressing is more effective than basal fertilizer on Zambian soils with average response rates of 4.2 kg/kg and 3.0 kg/kg respectively. This however masks a wide range of variability in fertilizer’s effectiveness. Top dressing response rates, for example, can be nearly 50% lower on coarse, sandy soils and on plowed fields where the majority of the topsoil is disturbed. Basal fertilizer is vulnerable to nutrient "lockup" in the acidic soils that prevail throughout Zambia. Average marginal yield response to basal fertilizer is just 2.1 kg/kg on the highly acidic soils where 51% of our sample fields are located. On semi-neutral soils, response rates can more than triple up to 7.6 kg/kg on average. Unfortunately, only 2% of our sample (and a similar proportion of all Zambian maize fields) are in areas where semi-neutral soils prevail. Given transportation costs and average products, this study demonstrates that fertilizer use is unprofitable for most Zambian farmers at commercial prices, which has important implications for the long-run viability of subsidy programs.

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Page publiée le 15 avril 2013, mise à jour le 28 août 2017