Reductions of Wheat Yield and Yield Components and Nitrogen Loss Following Frozen Soil Nitrogen Applications

Carrie Ann Knott, Edwin L. Ritchey, Lloyd W. Murdock
2015
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
more » ... d 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.
doi:10.13023/pssrr.2015.1 fatcat:lzg6xawidvdenprqwfzbw4mnku