Jarrod O. Miller, Extension Agronomist, jarrod@udel.edu
Proper establishment of small grains will ensure success when springtime temperatures begin to warm. Some practices that help with planting include germination tests, tillage (after corn), and planting during the optimal window (https://sites.udel.edu/weeklycropupdate/?p=12483). When considering planting rates, research at UD have not seen increased yields above 1.5 million seeds per acre (https://sites.udel.edu/agronomy/2020/10/01/2018-2020-wheat-seeding-rate-yields/). This follows many regional recommendations.
Planting rates are important to establish the maximum number of heads in the field, which is assisted by tillering in small grains. Good tillering reduces the need for higher rates, which is influenced by fall weather and soil nitrogen contents. By tracking wheat populations with drone imagery, we observed that lower populations added tillers in the spring but could not complete with proper fall establishment. Still, if stand counts in November don’t match your expected rate, be sure to track the fields through the winter and apply N to give plants the additional ability to add tillers and sustain themselves through freeze damage.
Landscape position (uplands, depressions, etc.) can also contribute significantly to small grain growth, where we have observed better growth in upland depressions that collect winter rainfall (Figure 1c). Just like summer seasons, excessive rainfall will cause the opposite effect (Figure 1b). We have also observed that steeper slopes reduce growth, but do not have any data to support higher or lower seeding rates in those parts of the fields.
Temperature can also influence excessive plant growth. Be sure to scout fields in January and February, as warmer winters may place your field ahead in tillering and growth stages. Make sure to apply spring N based on growth stages, and not calendar dates.
Figure 1: Wheat and barley fields at sidedress in 2019 (a, b), 2020 (c, d), and 2021 (e, f). Darker green represents greater plant growth and ground cover. Brown colors are likely bare soil. Black lines follow slope contours.