Effects of Nitrogen Fertilization on Manganese Concentration and Yield of Barley and Oats

Abstract

Abstract Response of barley ( Hordeum vulgare L.) and oats ( Avena sativa L.) to band application of N sources with and without Mn and the effects of band vs. broadcast application of fertilizers on the Mn concentration in leaves and yield of barley and oats were studied in the field in 1978, 1979, and 1980 on Lower Klamath Lake where Mn deficiency of oats had been observed in previous years. Experiments were established on a Tulana silt loam variant (medial, nonacid, mesic, Mollic, Andequepts). The pH of the soils ranged from 7.6 to 8.3 and the organic matter content was between 17 and 19%. Nitrogen was applied at 0, 22, or 45 kg N/ha as (NH 4 ) 2 SO 4 , NH 4 Cl, urea, and various urea‐phosphate (UP) formulations. Manganese was applied at 0 or 5.6 kg Mn/ha as MnSO 4 . All treatments received P at 19 kg P/ha as Ca(H 2 PO 4 ) 2 or 25 kg P/ha in the UP fertilizers, and Cu as CuSO 4 at 2.2 kg Cu/ha in 1978 and 5.6 kg Cu/ha in 1979 and 1980. ‘Cayuse’ oats and ‘Steptoe’ barley were planted at 110 kg/ha. Band application with the seed of 22 or 45 kg N/ha as (NH 4 ) 2 SO 4 or NH 4 Cl significantly increased both barley and oat leaf Mn concentrations and yields all 3 yr. Leaf Mn concentrations and yields were not increased by urea fertilization. When Mn was applied with the N fertilizer, leaf Mn concentrations and yields were similar regardless of N source. Broadcast application of fertilizers did not increase leaf Mn concentration or yield. The UP materials were intermediate in effectiveness between urea and (NH 4 ) 2 SO 4 .