Response of corn (Zea mays L.) to manganese application on Atlantic Coastal Plain soils

Field research was conducted on four Atlantic Coastal Plain soils in the United States to evaluate response of corn (Zea mays L.) plants to Mn application. The soils under study were classified as either Aeric or Typic Ochraquults. Manganese application increased corn grain yields by an average of 1195 kg ha^–1 on the four soils. The average grain yields on the soils were 7955 kg ha^–1 for the control and 9150 kg ha^–1 for the +Mn treatment. A Mitscherlich plant growth model was used to establish relationships between percent maximum grain yield and Mn concentration in the ear leaf at early silk (r=0.87, =0.01) and in the mature grain (r=0.58, =0.01). Based on 90% of maximum yield as the definition of the critical deficiency level, the critical Mn deficiency levels calculated with parameters from the Mitscherlich model were 10.6 mg kg^–1 in the ear leaf and 4.9 mg kg^–1 in the grain.