Effect of Soil and Foliar-applied Manganese on the Micronutrient Content and Yield of Soybeans1
- G. W. Randall,
- E. E. Schulte and
- R. B. Corey2
Manganese deficiency of soybeans (Glycine max (L.) Merr.) will undoubtedly become more prevalent as soybean acreage increases along with strong emphasis on yield maximization. Thus, field experiments were conducted on two soils (Argiaquoll and a Hapludoll) southern Wisconsin to evaluate sources, rates, and methods of application of Mn fertilizers on soybeans. Two sources, MnSO4 and Mn-ethylenediaminetetraacetic acid (MnEDTA), were broadcast, row or foliar-applied various rates to Mn-deficient soils and/or soybeans. Micronutrient concentrations, Mn uptake, and various production parameters were measured.
All rates and application methods of MnSO4 and foliar applications of Mn-EDTA were effective in supplying Mn to the plant. Row applications of MnSO4 were somewhat more efficient than broadcast applications. Manganese applied at rates ranging from 5 to 22 kg Mn/ha as MnSO4 with the starter fertilizer in the row at planting time appeared to be most efficient soil treatments in increasing seed yields. The MnEDTA applied in the row reduced plant weight, leaf Mn, and soybean yields slightly. When Zn was not included in the starter fertilizer, leaf Zn and Cu were increased by the soil-applied MnEDTA treatments. Leaf Fe was not affected by any of the Mn treatments.
Foliar applications of Mn were most effective when applied at the early blossom or early pod set stages or in multiple applications at these stages. Single applications of 2.24 and 4.48 kg Mn/ha as MnSO4 or 0.51 kg Mn/ha as MnEDTA caused some burning of the foliage.
Combined row and foliar methods of application also appeared to relieve Mn deficiency effectively. Small amounts of MnSO4 applied in the row corrected the Mn deficiency early in the season, whereas foliar applications adequately supplied Mn to the plant later in the growing season. This combination resulted in higher yields than with either row or foliar treatments applied alone.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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