Comparison potential yield and actual yield
In the example Spring crop El Kharj the actual yield of a specific existing crop is 25 tonnes and the calculated potential yield of an "ideal" crop is 46 tonnes.
EXAMPLE CALCULATION POTENTIAL YIELD
This is explained by a lower light interception of the specific crop (about 50% less) and a lower efficiency of the foliage utilizing the intercepted light for tuber production than the 'ideal' crop (about 30% lower).
% Soil cover "ideal" crop and existing crop
The actual yield to potential yield ratio is an indication of the technical level of production.
Estimates of the average actual and calculated potential yield in some selected areas
Conclusion:
The ratio of actual yield to calculated potential yield is an indication of the technical level of production.
In most countries in the tropics and sub-tropics it will not be possible to reach the levels of yield which are obtained in the temperate zones, due to the shorter growing season and a lower efficiency per unit of intercepted radiation because of high temperatures.