The cropping potential of South Africa: land evaluation results obtained during the last 50 years

摘要

Reliable detailed information regarding the crop production potential of a country is necessary for the planning and execution of the proactive activities needed to avoid future food shortages due to increases in population and/or adverse climatic conditions. The land-type survey of the Republic of South Africa at a scale of 1:250 000 provides a sound basic framework for the assessment of cropping potential because the delineation criteria incorporate the three natural resource factors that determinecropping potential, namely climate, topography and soil. Assessing cropping potential at regional scales, resulted in estimates of arable area between 16.4 and 28.6 million ha. It is clear from these results that a more detailed countrywide assessment at a much larger scale is essential to provide reliable information. The procedure already demonstrated for an area of 2.7 million ha in the eastern Highveld of South Africa is recommended for this work. Modern soil survey techniques can facilitate this enormous task. Detailed assessment of the potential of the 15 million ha occupied by subsistence farmers needs to receive the highest priority. The ecotope is a suitable land unit for assessment of cropping potential. Information derived from ecotope delineation has potential to be useful in agriculture and forestry.