By David Karki, Extension Agronomy Field Specialist
Corn and soybeans, two major South Dakota crops are warm-season species that, depending on their growth stage, can suffer significant detrimental effects from untimely snow and cold temperatures. However, another major South Dakota crop — wheat — can markedly benefit from the snow falling through the winter.
Winter wheat seeded in the fall germinates, grows roots, and gets well established before going dormant during the hard winters of the Northern Plains. If exposed consistently to sub-zero temperatures plant tissues can be damaged even permanently. Even though snow that comes with the onset of cool temperatures could be a nuisance for a number of daily activities we carry out, it can actually benefit winter wheat crop to a great deal.
Snow has two distinct benefits on winter wheat: 1) provide insulation for the young plants protecting them from fluctuation in air temperatures, and 2) provide soil moisture in the spring when snow melts. Although genetics play a good role for winter wheat’s ability to tolerate cooler temperatures, not having enough snow cover can impose a risk to any varieties planted, especially when temperatures consistently falls below zero.
Another weather factor that can be damaging to winter wheat crops is the freeze-thaw cycle during the winter. Last year, multiple days in January had above freezing temperatures, which caused permanent damage to some winter wheat fields. Low temperatures following thaw periods can further cause ice accumulation on the soil surface and in some cases even lift the “crown” or the growing point of the plant above soil surface, making it more susceptible to winter kill.
Depending on the overall winter temperatures, 3-6 inches of snow cover can help to a great extent for winter wheat survival. Snow-covered winter wheat fields generally show better crop stand in the spring.
Wheat is a major field crop in South Dakota. In the fall of 2015, more than 1 million acres of winter wheat was planted. Spring wheat, which as the name suggests is seeded in the spring, can also benefit from melted snow as soil moisture is a critical factor in germination and early establishment.
South Dakota is a unique wheat growing state in the U.S. as both types are grown in almost equal proportion. Although snow makes farm chores sometimes difficult, it plays a role in ensuring a healthy winter wheat crop the following season.
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