DIAGNOSING THE NITROGEN AND MINERAL ELEMENT REQUIREMENTS OF GREENHOUSE VEGETABLE CROPS BY MEANS OF FOLIAR ANALYSIS
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