Tobacco as an indicator plant in studying nutritional deficiencies of soils under greenhouse conditions
1929
Morgan, M.F.
Tobacco (Turkish) has been used with very successful results as an indicator plant to show the fertilizer response of soils under greenhouse conditions. A deficiency in available supply of a nutrient element is evidenced by significant yield reduction and physiological characteristics of tobacco grown on soils unfertilized with that particular element. No correlation between response and total amounts of nitrogen, phosphorus, or potassium was observed on any of the 24 different soil types under investigation, but a good correlation existed between phosphorus response and amounts of soil phosphorus soluble in 0.01 N sulfuric acid as determined by the coereleomolybdate method. Potassium availability was apparently reduced by liming under the conditions of these experiments. Lime had no beneficial effect except on soils at pH values below 4.8 pH. On soils below 4.2 pH abnormal plants were produced, and the injurious effects of this degree of acidity may be associated with toxicity of soluble aluminum or manganese, or both. Data given in this paper are incidental to the discussion and final conclusions should not be attempted until the investigations are concluded.
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