Case study sitesThe authors selected three case study regions in contrastingagro-ecologies: the (semi-)arid State of San Luis Potosi in north-central Mexico; the temperate highlands in the central State ofMexico; and the (sub-) humid tropical lowlands in the south-eastern State of Chiapas (see Fig. 1). Field research took place in12 communities (four communities in each of the three regions)(Table 1). There are socio-economic differences between theregions even though all have mixed (crop–livestock) systems. Ruralpoverty tends to be least in the State of Mexico, which benefits fromits central location and proximity to the capital. Rural marginal-ization tends to be higher in San Luis Potosi and even higher inChiapas.The surveyed municipalities in the State of Mexico are predom-inantly agricultural (74% of land), versus less than a third in thetwo other study regions (Table 2). In contrast, the San Luis Potosisurvey region has a third of its area classified as desert vegetation.The Chiapas region is relatively similarly divided into agriculturalland, forest, fallow and grassland. The topography in both the Stateof Mexico and Chiapas survey regions primarily comprises valleyswith hills – albeit in a highland and lowland setting, respectively.The population density in the surveyed municipalities of the Stateof Mexico is markedly higher than in the two other study regions,associated with an equally marked divergence in terms of farm-ers’ average landholdings (only 1.5 ha in the State of Mexico regionversus 9–10 ha in the other regions).Maize occupies a fifth of the cultivated surface in the San LuisPotosi survey region compared to more than 50% in the two otherregions. Maize production is primarily rain-fed, although a fifth ofthe maize area in the State of Mexico survey region was irrigated. InChiapas, there are relatively high livestock densities per unit areacultivated, 2.5–3 times those for the two other regions. However,the relatively limited maize area share in the San Luis Potosi surveyregion implies it overtakes Chiapas in terms of livestock densitiesper unit maize area. The three study regions also have elements incommon, including a longstanding tradition of maize cultivationand stover use as cattle feed. The mixed systems also face prob-lems of soil degradation and low profitability and often competingdemands for maize stover.