RESEARCH ABOUT MANGANESE REGIME FROM AGRICULTURAL ECO-SYSTEMS IMPROVED BY THE SEWAGE SLUDGE

Mn is another element in the category of heavy metals, which in small quantities is useful in feeding the plant, while the excess could induce specific phytotoxic phenomena. For the purpose of observing trends of Mn content of plants were used progressive sludge doses: between 0 and 50 t, ha(-1), with doses of chemical fertilizer: 0, 1/2 and 1/1 of crops specific needs. In general, mobile Mn ranged between 400 and 650 mg, which are relatively high concentrations. Under these conditions the plants have absorbed field Mn2+ ions in specific quantities. The correlations obtained between the contents of Mn and complex doses shows obvious increase in leaves of maize (r=0.832***) and soybean (r=0,530*), inconclusive in wheat (both years), and decreased concentrations of Mn in the three species grains. Such researches might reveal some aspects in relation to nutrition with micronutrients such as Mn, of each plant part.