2. The Effect of Soil Type and Fertilization on the Composition of the Expressed Sap of Plants1

Abstract

Greenhouse samples of barley, sugar beets, field beans, and red clover, and field samples of celery, cabbage, sugar beets, wheat, and rye have been studied as to the content of certain mineral nutrients in the expressed juice. Field samples generally contain more of these nutrients than greenhouse samples. The percentage of each nutrient in the juice of the leaves is usually greater than in that of the stems, but in rainy weather potassium may be leached from the leaves to a greater extent than from the stems. Applications of the various mineral nutrients to the soil as fertilizer generally result in increased concentrations of those elements in the juice of the crop. If one element is decidedly a limiting factor, the slow growth of the plant appears to permit the accumulation of high concentrations of other elements. Under these conditions, applications of the limiting element to the soil as fertilizer are likely to decrease the concentrations of the other elements in the plant.