Productividad del tepetate con sistemas rotacionales | Productivity of hardened volcanic soil under rotatory systems

Hardened volcanic soils have their origin in horizons that protrude on the surface because of erosion caused by bad management. In Mexico, they occupy an area of more than 300 thousand ha; the area is important in Latin America. At present, these soils are of interest for agricultural production. However, knowledge of annual and accumulated productivity on medium and long-term bases is insufficient. The methodology identified fragipan soil as the tepetate that occupies the largest area and, as a consequence, was selected to evaluate its productive limitations and to prospect alternatives. The five-year experimental design integrated local cultural practices, and local crop patterns with four rotation models, T-A-T-T-A, V-A-T-T-A, Ai-A-A-T-A, and A-A-A-T-A (Ai = intercrop corn-broad bean or bean inoculated with rhizobium, A = intercrop without inoculation, T = wheat, and V = Vetch) and six random blocks with the application of animal manure in three blocks on two occasions and three blocks without application. The accumulated annual production of total biomass and grain tend to increase with the number of years of agricultural use of tepetate. The tendency presents irregularities influenced by yearly climatic characteristics and other limiting factors. The average annual production of grain and total biomass tends to be appreciably superior with the application of animal manure, compared with the control. The four rotation models showed productive potential as well as a positive effect of the application of animal manure, in comparison with the control, for both total biomass production and grain production. The highest accumulated production of biomass area and grain in the rotation system Wheat - Association (corn-bean) - Wheat - Wheat Association (corn-broad bean) was statistically equal to the rotation system Vetch-Association (corn-bean) - Wheat - Wheat - Association (corn-broad bean). The development of the productive ability of the hardened volcanic soils through local rotational models is a technical alternative.