While this past Thursday’s snow made for a bit of a rough drive, it was very welcome and not just for farmers and ranchers. This snow, combined with the rain from the past week, was important and not just as moisture for winter wheat, winter canola, and next spring’s planting. What are the additional benefits of this moisture that many forget about?
• Root and growing point cells with adequate water are better able to withstand cold temperatures than cells under dry soil conditions. Proper turgor pressure is vital in protecting plant cells from the effects of cold. Winter kill is often worse for winter wheat when cold is combined with dry soil conditions. Desiccation combined with cold typically does much more damage than cold alone.
• Moist soil retains more heat than dry soil. Water has a higher heat capacity than the mineral and organic components of soil. While it takes longer to warm moist soil, it also cools more slowly and the daily temperature fluctuations are less. This provides a more stable and warmer soil environment to protect overwintering plants. Wider swings in soil temperature are potentially more damaging to plants than a more constant or slowly increasing or decreasing temperature.
• Snow cover does indeed act like a blanket and serves to insulate overwintering plant roots and growing points. This snow barrier serves to keep heat in the soil. And it can also serve to protect the above ground vegetative parts of plants over winter.
• Rainfall on plants that then freezes on above ground parts serves to help insulate the plant from below freezing temperatures. Also as the liquid water freezes it gives off a bit of heat to protect tender plant parts.
• Soil moisture in late winter/early spring helps fall planted crops like canola and wheat, as well as perennial grasses and alfalfa get off to a good start. In the case of wheat and canola it can help these crops outgrow damage from larvae such as army and cut worm. Plants in dry soils grow less vigorously and since they are stressed they are more susceptible to climate extremes and pest pressures.
• The application of herbicides on overwintering crops is more effective when the weeds are in good condition and able to actively take in and metabolize the herbicide.
• Producers who have limed need soil moisture to have the chemical reaction that ameliorates acidity and raises pH to proceed. While we may not be thrilled with the snow, it is vital to crops and other plants in many ways beyond what we first think of.