Studies in Soil Manganese: II.: Extractable Manganese and Plant Uptake1
- I. H. Salcedo,
- B. G. Ellis and
- R. E. Lucas2
Results from a greenhouse pot experiment with 12 Michigan and Indiana soils of different characteristics were used to evaluate effectiveness of six extractants in predicting Mn uptake by soybean (Glycine max., cv. Hark) plants. Three levels of Mn as MnSO4 were added to each soil. Correlation between extractable Mn and uptake of Mn by plants decreased in the following order: 0.1N H3PO4 > steam/1N NH4OAc > 1.5M NH4H2PO4 > 0.1N HCl > 1N NH4OAc > 0.005M DTPA. Inclusion of pH and (Ca+Mg)/K ratio in prediction equations for each soil test increased percentages of variation in uptake data explained by the tests. Of the soil characteristics, Mn oxide fractions explained 66% of the variation in Mn uptake; inclusion of pH, bases ratio and total Mn in the equation accounted for 82% of this variation. Critical levels of extractable Mn in these soils were 12 ppm for 0.1N H3PO4 and 14 ppm for steam/1N NH4OAc or 1.5M NH4H2PO4.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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