Correlation of Plant Tissue Tests of Corn, Deficiency Symptoms, and Soil Analyses on the Jordan Fertility Plots

Abstract

AbstractAlthough soil tests, tissue tests, and visual deficiency symptoms have been used rather extensively by many agronomists for the diagnosis of nutrient deficiencies existing in soils and plants, no comprehensive comparison of the interrelationship of those methods of diagnosis is available. Therefore, it was the purpose of this investigation to determine the correlation and relationship of these diagnostic methods to each other for nitrogen, phosphorus, potassium, and magnesium with corn as a test crop. The Jordan fertility plots served admirably as a source of material for such an investigation since they were established in 1881 and have attained stable fertility levels, depending upon the fertilizer treatment of each plot. Two corn hybrids (Ohio K‐24 and Ohio M‐15) were grown on each of the 36 plots on tier 1 in 1948 and again on tier 2 in 1949.The soils were analyzed for available nutrients according to standard accepted methods. Potassium and nitrogen tissue tests were made according to the descriptions of Richer2 and Kohnke3, respectively. The tissue test for phosphorus, as described by Kohnke3, was modified and a tissue test for magnesium was developed. Visual deficiency symptoms for nitrogen, phosphorus, potassium, and magnesium were evaluated on each plot for each of the two corn hybrids. The deficiency symptoms described by previous workers were found to be a reliable guide for distinguishing the plant nutrient deficiencies of nitrogen, phosphorus, potassium, and magnesium.When soil tests, tissue tests, and deficiency symptoms were compared on tiers 1 (unlimed) and 2 (limed) of the Jordan fertility plots with two corn hybrids (Ohio K‐24 and Ohio M‐15), the following conclusions appeared justified.Nitrogen. — An excellent correlation at the 0.1% level of significance was found between tissue tests and visual deficiency symptoms on tiers 1 and 2; however, no correlation was found between the tissue tests and potential nitrification of the soil or visual deficiency symptoms and potential nitrification of the soil.Phosphorus. — Highly significant correlations were found in all instances, namely, between (1) soil tests and tissue tests, (2) soil tests and deficiency symptoms, and (3) tissue tests and deficiency symptoms.Potassium. — All correlation coefficients were significant at the 0.1% level between exchangeable soil potassium and tissue tests, exchangeable soil potassium and deficiency symptoms, and tissue tests and deficiency symptoms.Magnesium. — The correlation coefficients between exchangeable magnesium and tissue tests on the limed tier were not significant at the 5% level but were significant on the acid tier. Significance at either the 1% or the 0.1% level was found between exchangeable soil magnesium versus deficiency symptoms and tissue tests versus deficiency symptoms.Good correlations were obtained in most instances between soil tests, tissue tests, and deficiency symptoms, but no one test is always conclusive.