All crops can be sensitive to heat stress, especially during the flowering stage. Even short periods of heat stress during flowering and grain fill can cause substantial yield losses.
Flowering, one of the most important stages in a crop’s life cycle, often happens during the hottest days of summer. As the plant is shifting the bulk of its energy production to flowering, it must also contend with stress brought on by high temperatures. The resulting water loss at the peak of evapotranspiration forces stomata to close, jeopardizing nutrients and water uptake.
In canola, heat stress can cause a condition called “heat blast aka pod abortion,” characterized by a higher than usual number of aborted flowers, causing blanks on the stem, and flowers with shortened stamens, which do not produce pods. In cereals, heat stress causes poor grain filling.
During periods of heat stress, it is especially important to pay attention to boron (B). Boron is a micronutrient that is critical to the growth of pollen tubes and the germination of pollen grains and fertilization, helping to ensure good grain fill and yield. Boron is immobile in the plant and cannot be stripped from leaves to meet the increasing demand by the flowers.
Although a plant’s boron requirements are relatively low compared to other micronutrients, it’s important to maintain an adequate level throughout the crop’s life cycle, supplementing as necessary during the reproductive stage, when plants have an increased need for B.
Providing a readily available supply of boron at flowering time can optimize pollination for better seed fertilization and development, reducing plant-stress and protecting yield. Applied during the flowering stage, a liquid foliar fertilizer with a high analysis of boron can help to promote pollen formation and fertilization and relieve heat blast.
Formulated to reduce the point of deliquescence for improved uptake during hot, dry conditions, Super B (10% B) and KB78 (8% B) both provide boric acid, the most available form of boron. KB78 also contains potassium (7% K) to mitigate K deficiency, a common occurrence during hot weather.
Talk to your retailer or OMEX sales representative for more information on helping your crops beat the heat with stress-relieving boron.