This paper uses a multinomial endogenous treatment effects model and data from a sample of over 800 households and 3,000 plots to assess the determinants and impacts of adoption of sustainable agricultural practices (SAPs) on maize yields and household incomes in rural Zambia. Results show that adoption decisions are driven by household and plot level characteristics and that the adoption of a combination of SAPs raises both maize yields and incomes of smallholder farmers. Adoption of improved maize alone has greater impacts on maize yields, but given the high cost of inorganic fertiliser that limits the profitability of adoption of improved maize, greater household incomes are associated rather with a package involving SAPs such as maize-legume rotation and residue retention.

Agronomic research on crop response to nitrogen fertilizer suggests that a plateau function may be appropriate, but the plateau varies across fields and years. Available models that treat the plateau as a stochastic variable are not readily extendable to handle field or year random effects as seems to be appropriate based on the agronomic data. This article develops a method of estimating a response function with a stochastic plateau that can capture random effects. The method is then used to determine economically optimal levels of nitrogen fertilizer for wheat (Triticum aestivum). Copyright 2008, Oxford University Press.

In Africa, state-sponsored cash transfer programs now reach nearly 50 million people. Do these programs raise long-term living standards? We examine this question using experimental data from two unconditional cash transfer programs implemented by the Zambian Government. We find far-reaching effects of the programs both on food security and consumption as well as on a range of productive outcomes. After three years, household spending is on average 67 percent larger than the value of the transfer received, implying a sizeable multiplier effect, which works through increased non-farm activity and agricultural production.

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