INCREASING VEGETABLE CROP PRODUCTIVITY

The purpose of vegetable production is to produce as high a yield of marketable product as is possible within the current economic constraints. Over the years excellent research has been undertaken on such important factors as crop physiology, crop establishment, plant spacing, nutrition, irrigation, timing of harvest, pest and disease control and various aspects of plant breeding. All of these factors (and others ) can have a major impact on productivity, but commonly they are regarded independently rather than as an interacting system. In fact irrespective of whether we are growing in the field or in a greenhouse we are converting solar energy into chemical energy of an acceptable form, which is pleasant to consume and of nutritional value. Quality (in its widest sense) is a most important criterion. To produce heavy yields of high quality vegetables at the appropriate time for the market demands a high level of knowledge, of all those factors which influence productivity, and because all these factors interact, then the poor performance of a single factor can cause significant reduction in yield. Similarly getting these factors right (or nearly so) can result in huge yield increases. It is the role of the vegetable scientist to determine the relative importance of these different factors, and what level of control we can exert on them, and what is outside our control. We will then be in a better position to not only influence yield, but also of equal importance) be aware of our limitations in controlling yield in the natural environment. In the final analysis we must always remember that yield is a function of genotype and environment.