Implementing the Conservation Agriculture Concepts in the Irrigated Wheat Based System of North Mexico; A Dynamic Process Towards Sustainable Production

Abstract

In this paper we use the example of the irrigated wheat based systems of North Mexico as a typical example of a step-by-step process to advance the use of Conservation Agriculture based Resource Conserving Technologies towards the final goal of the implementation of Conservation Agriculture. Sonora in northwest Mexico. This region is characterized by a desert climate, mostly sunny and dry with a total rainfall of about 381 mm per year with 253 mm during the summer cycle (May – Oct). The Yaqui Valley is one of the main agricultural production areas encompassing nearly 255,000 ha of irrigated land using primarily gravity irrigation systems fed by canals (over 80% of irrigation water) and deep tube wells (around 20% of irrigation water). Crops planted during the winter cycle are wheat (November-May),safflower (January-June), winter maize (September-February), chickpea (December – April) while during the summer cycle summer maize (May – October), sorghum (March – July), dry beans (March – May) are most common. There have been 3 main shifts in farming system practices during the last decades: (1) In 1981, the majority of the farmers were planting with ‘melgas’ (crops planted in solid stands on the flat with flood irrigation in basins) with only 6% of farmers in the valley planting on raised beds. However by 1996, 90% of the farmers had shifted to planting on raised beds. The great benefits from bed planting are reduced production costs, reduced irrigation water use, enhanced field access which facilitates control of weeds and other pests, and timely and efficient application of nutrients, reduced tillage, and crop residue management. (2) Another remarkable change in farmer practices has been crop residue management. In the 1992/93 cycle, residues were burned by 95% of the farmers. This practice was deeply entrenched. By 2001, however, 96% of the farmers are no longer burning but incorporating the residue. (3) Recently there is growing interest to take the next logical step in making raised bed planting more sustainable by reducing tillage and manage crop residues on the surface by reusing permanent raised beds with only superficial reshaping in the furrows between the raised beds as needed before planting of each succeeding crop, following even distribution of the previous crop residues. Therefore in 1991 the crop management team at CIMMYT started research on permanent beds to offer farmers opportunities to further reduce production cost andincrease sustainability of the system through the positive effects on chemical, physical and biological soil quality.status: publishe