It is quite clear (Beeson, 1941) that factors other than the availability of a nutrient influence the concentration of that nutrient in the plant. If the concentration in the plant of a given nutrient is to be used as a measure of the availability of that nutrient in the soil, then the other factors affecting the concentration must be evaluated so that correction factors can be established or else a method of sampling must be evolved in which the influence of the factors is negligible. Previous work by several authors indicates that sampling error can be reduced if the morphologically same tissue is sampled each time. The author, (1944) found that an extract of the spinach petioles more clearly mirrored the change in availability of a particular nutrient than did an extract of the blades or roots. However, Brown (1943) found a wide difference in the concentration of nitrate nitrogen and soluble phosphorus between young and old petioles of sugar beets harvested the same day from the same plants. The present work is an effort to evaluate the effect of the age of the plant, the age of the petiole at a given harvest date and also whether the dry weight base is a more desirable base than the fresh weight base.
Proceedings of the Iowa Academy of Science
©1945 Iowa Academy of Science, Inc.
Harrington, James F.
"The Trend of Soluble Nitrate, Phosphate and Potassium Concentrate in the Development of the Spinach Petiole,"
Proceedings of the Iowa Academy of Science, 52(1), 121-126.
Available at: https://scholarworks.uni.edu/pias/vol52/iss1/16