Responses of plants to additions of manganese to some Oregon soils
1945
Marsh, A.W. | Powers, W.L.
The soils studied in this paper that showed a need for manganese occupy a small proportion of the total cultivated land in Oregon. Those soils that need manganese are not widespread and the deficiencies that do exist are not acute as crops grown on them do not show severe disease or deficiency symptoms. Manganese has induced certain increases in yield and quality of crops from some peat soils which make its use desirable under intensive cultivation. These are the basic peats and a coarse acid peat alternately submerged and desiccated. Acid peats and mineral soils are not likely to respond. The peat soils, except Braillier peat, have a rather high manganese fixation capacity so that relatively large applications could be made without toxic effects. On the basis of yields obtained and the amount remaining available in the soil it would be more feasible to make moderate applications yearly. In the plant leaves analyzed the manganese level varied from 40 to nearly 700 p.p.m., in the other plant parts from 20 to 170 p.p.m. An indication is provided of response to manganese when the leaf content is less than 100 p.p.m. No distinct disease symptoms appeared at the 40 p.p.m. level though it was thought to be near the borderline. Gilbert, et al. (6) found that the manganese requirement of oats and spinach was 20 to 60 p.p.m. In the soil active manganese varied from 12 to 1,326 p.p.m. These extremes probably are in the range of deficiency and toxicity. The degree of responses did not associate well with any definite level probably because of other factors in the soil. Soils containing an excess of active manganese with all its physicochemical and physiologic reactions may be found in some of the residual hill lands.
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