ISHS Acta Horticulturae 4: Symposium on Vegetable Growing under Glass
DIAGNOSING THE NITROGEN AND MINERAL ELEMENT REQUIREMENTS OF GREENHOUSE VEGETABLE CROPS BY MEANS OF FOLIAR ANALYSIS |
| Author: | F.S. Howlett |
| Abstract:
On July 1, 1964, the first foliar analysis service in the United States was established in Ohio to ascertain for the benefit of greenhouse vegetable growers the precise nutrient element status of their current crops. This development was not an isolated incident, but in fact marked the culmination of twenty years of research along this line. The research program carried out at the Ohio Research and Development Center involved tomato, cucumber, Bibb and leaf lettuce as well as thirteen other vegetables growing under field conditions. Since initiation of the program results have greatly exceeded expectations at the time of its formulation. It has been possible as never before to evaluate the role of a given nutrient element or combination of elements in restricting growth and yield. This information is obviously of great importance since so many other factors, such as air temperature, light intensity, water supply, soil aeration and compaction, insect and disease damage, and the like, are often the detrimental factors rather than a deficiency or excess of an essential nutrient element. In 1944 more than thirty-five commercial greenhouses, located in every section of the State participated in an extensive survey designed to ascertain both by means of soil and leaf analyses the nutritional element status then obtaining in the growing plants. A wide range in concentration of the various elements was | |
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