A comparison of manganese effects of semanox and manganese sulphate in relation to yield and development of oats

Abstract

The manganese of Semanox (about 54 per cent Mn as MnO) and manganese sulphate (MnSO4.H2O, 32,5 per senc Mn) where studied over a 4-year period in a pot experiment with a Mn-deficient sandy soil with pH (H2O) 7.8. Oats were used as a test crop. The Mn-ferilisers were applied before planting at the beginning of the experiment and incorporated in the soil at rates of 0, 33.75, 67.5, and 337.5 mg of Mn per pot. The first year, at all Mn-rates compared, Semanox proved more effective as a Mn source than Mn sulphate. The second year, only the highest rate of Mn gave a satisfactory yield; the last two years, however, the Mn supply was too low even at the highest rate, wether it was applied in form of Semanox or in form of Mn sulphate. A comparison of Semanox and Mn-sulphate at the highest Mn rate, and for the whole 4-year period, showed no significant yield differences. Semanox incorporated in the soil has also been testet in field trials on Mn-deficient sil loam (pH 6.1-7.1). Test crops have been small grains. Compared with Mn sulphate no significant yield differences were found. In these trials only leaf fertilisation with Mn sulphate gave satisfactory yield responses.