Potential production and yield gaps

Assuming no limitation by water and nutrients on one hand, and a field free of weeds, pests and diseases on the other, crops attain their potential yield level as defined by their genetic make up and climatic conditions (solar radiation and temperature).

Actual yields, especially in Africa and SE Asia, are substantially lower than potentially attainable. Understanding these ‘yield gaps’ by using crop simulation models based on both plant, soil and climatic factors, will help to formulate measures to step up actual production (apart from socio-economic considerations). African soils in particular have shown to be poor in nutrient content, implying that even in drier parts productivity could be increased by fertilization rather than irrigation. Models also help to understand the impact of climate change on crop production by various soils world wide.

The previous classification indicates to which extend yield gaps can be bridged by applying yield increasing (fertilization or irrigation), or yield protecting measures, as recommended in Africa and some parts of Asia. In some Western countries, where yield gaps become practically closed, further production gains require unconventional techniques, including biotechnology and soilless cultures in greenhouses.

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