Evaluation of Narrow-Row Corn Forage in Field-Scale Studies
2002
Cox, William J. | Cherney, Debbie J. R.
Some dairy producers in the northeastern USA grow corn (Zea mays L.) in narrow rows at high plant densities and N fertility. We evaluated first-year, second-year, and continuous corn in field-scale studies at 0.76- and 0.38-m row spacings at recommended densities (≈85000 plants ha⁻¹) and N fertility (≈165 kg ha⁻¹) and at 0.38-m spacing at high densities (≈100000 plants ha⁻¹) and N fertility (≈225 kg ha⁻¹) in 1998, 1999, and 2000 to determine if narrow-row corn forage requires high densities and N fertility for optimum yield and quality. Narrow-row corn at high vs. recommended densities and N fertility had similar soil NO₃–N concentrations in the upper 0.3-m depth and whole-plant N concentrations at the sixth leaf stage of corn (V6) as well as similar ear-leaf N concentrations at silking in eight of the nine site-year comparisons. All treatments were above critical concentrations for soil NO₃–N concentrations (>25 mg kg⁻¹), whole-plant N concentrations (>35 g kg⁻¹), and ear-leaf N concentrations (>25 g kg⁻¹, except in the cool 2000 season). Consequently, narrow-row corn at high vs. recommended densities and N fertility had similar dry matter yield and quality in eight site-year comparisons. Furthermore, narrow-row corn at high vs. recommended densities and N fertility had greater residual soil NO₃–N concentrations in three site-year comparisons. We recommended that dairy producers in the northeastern USA grow narrow-row corn forage at recommended plant densities and N fertility.
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