Resumo

DELGADO, Rodolfo  e  SALAS, Ana Mireya. Considerations for the development of an integral evaluation and management system of soil fertility and fertilizer applications for sustainable agriculture in venezuela. Agronomía Trop. [online]. 2006, vol.56, n.3, pp.289-323. ISSN 0002-192X.

The development of a sustainable agriculture would require integral mechanisms to evaluate and to manage soil fertility, and to recommend mineral or organic fertilizer rates in accordance with environmental, economical, and harvest quality requirements as well as with farmer capabilities. In this paper we proposed a strategy to develop an integral system, based on 1) fate of nutrients, and other important elements, in the soil-water-crop-atmosphere system (i.e. C-CO₂), 2) most important bio-physical characteristics of the soil and climate, at homogeneous units of land, 3) effect of management practices on specific soil properties, 4) farmer expectations in relation to yield quantity and quality, 5) technical and economical capabilities of the farmer, 6) nutritional requirements and crop growth characteristics of specific varieties or hybrids, 7) characteristics of traditional and alternative nutrient sources, 8) acceptable limits of emissions of gasses and nutrients to the atmosphere and water, and disposal of agricultural bio-products. In this proposal we suggest the use of mechanisms able to integrate the main processes of the soil-cropclimate system to simulate crop growth, soil properties related to soil fertility and soil quality, and the fate of nutrients in the system, in addition of allowing the prediction of nutrient availability in the soil profile. Also, the proposed integral mechanism could be useful to teach and to study sustainability issues and soil processes associate with soil fertility, and to detect research needs.

Palavras-chave : Soil fertility; sustainability; fertilization; nutrient cycling.