Most wheat producers in Kentucky apply nitrogen (N) as a split application. The first N increment is applied when wheat plants begin actively growing (green-up) in late winter, which is typically in mid- February between growth stages Feekes 2 to 3. The second N increment typically occurs in March when wheat is between Feekes 5 to 6. Many producers in Kentucky, especially Western Kentucky, have become accustomed to beginning first N applications in late January when the ground is frozen and the wheat is still dormant. This practice allows them to apply N to large acreages of wheat while avoiding rutting and/or compacting fields with large equipment. In most years, the soil will thaw within a few hours or days following N applications, which allows N to infiltrate the soil profile and reduce runoff potential. In 2014 Kentucky had below average temperatures for January and February (UK Ag Weather Center, 2013) resulting in frozen soil until mid-February throughout much of the state and delayed wheat development two to three weeks. In 2014, some producers made early N applications in January to dormant wheat grown on soil that was frozen to a depth of six to nine inches. This study was conducted to estimate grain yield response and N loss and to determine the yield components contributing to changes in grain yields when N was applied to frozen ground.
Digital Object Identifier
Knott, Carrie Ann; Ritchey, Edwin L.; and Murdock, Lloyd W., "Reductions of Wheat Yield and Yield Components and Nitrogen Loss Following Frozen Soil Nitrogen Applications" (2015). Plant and Soil Sciences Research Report. 1.