Growth and Manganese Uptake by Potatoes as Related to Liming and Acidity of Fertilizer Bands
1970
White, R. P. | Doll, E. C. | Melton, J. R.
The effects of liming and of the acidity of fertilizer bands on the growth and manganese uptake by Norland and Sebago potatoes (Solanum tuberosum L.) were determined on an acid sandy soil in a greenhouse experiment. Four levels of two sources of lime were established and four additional unlimed treatments consisted of: a) no supplements to the fertilizer band, or the addition b) of Al, c) of Mn, or d) of both Al and Mn in the fertilizer band. On all treatments, the equivalent of 1,000 pp2m of a 5-20-20 fertilizer was banded. Changes in soil pH and the pH in the fertilizer bands during the growing period were determined by direct contact pH measurements made through access tubes. Symptoms of Mn toxicity (chlorosis and black specks on the stems and undersides of the leaves followed by death of the lower leaves) were observed on those plants grown on the unlimed soils, and on those containing very high levels of Mn. When the soil was limed to pH 6.5 or above, Mn levels in the plants were markedly decreased and the toxicity symptoms disappeared. Additions of Al to the fertilizer band markedly lowered band pH but had little effect on plant Mn content. Additions of Mn to the band did not affect band pH, and increased plant Mn only slightly. The Norland variety was less tolerant of high Mn levels than was the Sebago variety. The uptake of Mn by the potato plants in this experiment was related to soil pH rather than to the acidity of the fertilizer band.
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