| Abstract: | Relationship between Mn in Oat Plants and Soils The Mn concentration of oat plants in the stage of appearing panicles from agricultural fields were put in relationship to extractable Mn. With soils of sandy texture (clay < 4%, pH 4,7–6,6) a correlation existed between Mn in plants and n-MgCl2 extractable Mn, however, no additional relationship with the easyly reducible Mn. A negative correlation between pH and Mn in plants was traced to the pH dependence of exchangeable Mn. With soils of loess (clay 5–28%, pH 6,6–7,7) a significant correlation existed between Mn in plants and easyly reducible Mn fractions (methods by Schachtschabel: extracting solutions containing Na2SO3, pH 8,0, or Na2SO3 + NaHSO3, pH 5,5), however, only if an interrelationship with the pH of the soil was allowed for. The higher the pH of the soil the lower its level of extractable Mn might be, to reach a certain concentration of Mn in plants. This relationship seems to be caused through a modifying influence of the soil pH on the reducing power of the extracting solutions. |
