Cultivating Maize with Mucuna in the Los Tuxtlas Region of South-eastern Veracruz, Mexico

Summary

Los Tuxtlas, a region of volcanic hills in southern Mexico, has high rainfall (1200–2500 and up to 4000 mm per annum) but soil fertility has decreased 70–75% in the past 40 years. Maize (Zea mays L.) is the subsistence crop in the region and is typically cultivated in sole-cropped conditions, with or without a short fallow, and with residue burning. Yields of summer maize (planted in June and averaging 1.2 t ha⁻¹) and the relatively less important winter maize (planted in October–November and averaging 0.5 t ha⁻¹) are low, seemingly mostly caused by poor soil fertility. Two Mexican non-governmental organizations, Proyecto Sierra de Santa Marta and Desarrollo Comunitario de Los Tuxtlas (Community Development of Los Tuxtlas), introduced Mucuna pruriens (L.) DC. to the region’s farmers as a means of improving soil fertility. This introduction was achieved by conducting campaigns through farmer extension workers (promotores) and adaptive on-farm research (1992–2000). Typically, Mucuna was intercropped between summer maize rows in August (40–70 days after summer maize planting). It was then either slashed in late October and winter maize planted in the dead mulch (summer-winter maize system) or it was left to continue growing and no winter maize planting took place (summer maize system). Before the following summer maize harvest, all crop residues, including those of Mucuna, were typically burned. Research efforts (and some of traditional use) in the region also focused on a rotational system where Mucuna was sole-cropped during summer and was followed by winter maize. On-farm assessments revealed that Mucuna could grow well in the region (particularly if grown during the high rainfall summer season as in the rotational system) and exert a strong, positive impact on winter maize yield (particularly in the rotational system). Allocating the main maize cropping season, summer, to Mucuna (as is done in the rotational system) is questionable. Positive impacts on summer maize yield are either not found or are inconsistent.

Cost-benefit studies reveal that maize production systems with and without Mucuna have an extremely low profitability because of low maize prices and yields, and the lack of multiple uses and consequently of markets for Mucuna seed. While some studies on farmer perceptions of the Mucuna technology have been conducted, no formal adoption studies have been made in the region. Mucuna use seemingly varies by community and has greatly fluctuated in response to the various extension efforts. The future of Mucuna in the region depends on a number of factors, not least of them the general economic policies of Mexico. Development and policy, as well as a research agenda, are outlined for improved adoption and positive impact of the Mucuna technology in the region.

Rockefeller Foundation-funded Post-doctoral Fellow