Appropriate plant nutrient management for sustainable agriculture in Southern Africa

Sustainable agriculture encompasses three facets ecological sustainability, economic sustainability, and socioeconomic sustainability. The three facets of sustainability are interlinked. This article focuses on soil fertility management in relation to these three facets of sustainable agriculture. Appropriate input levels are determined by the nature of the natural resources, especially soil and climate, and benefit to cost ratios. The appropriate type of input for a specific situation is determined by the levels of deficiency of specific nutrients and the type of fertilizer material available. Application of appropriate levels and types or inputs is critically important in many areas that are marginal in regard to climate and/or soil, which perforce have to be cropped in many developing countries. Several factors, such as land tenure systems, infrastructure, input subsidies, price control, etc., strongly influence the inputs made and the sustainability of agriculture. Results from decades of fertilizer experiments by the FAO in various countries and various other case studies are used to illustrate the principles involved. The need for appropriately equipped soil and plant analysis laboratories in developing countries is emphasized.