The extreme drought of last fall, coupled with a couple of very cold temperature plunges in December and January has raised concerns about the possibility of winterkill and poor wheat stands this spring. Crop specialists from universities and from Syngenta recommend wheat growers scout fields for signs of winterkill over the coming weeks and assess stands to identify potential damage.
"Drought is one stress that will be compounded with another stress – for example, the low temperatures. Drought and limited snow cover typically increase the possibility of winterkill in wheat," said Joel Ransom, extension agronomist at North Dakota State University.
"Four inches of snow is an amazing insulator; where the surrounding temperature may be minus 40 degrees Fahrenheit, crown temperatures with four inches of snow cover never go below 20 degrees Fahrenheit," said Jochum Wiersma, extension agronomist at University of Minnesota. "With limited snow cover and the fluctuation between mild to very cold temperatures, the chances for winterkill increase."
Fluctuations in temperature
Kansas growers saw wide swings in temperature, especially in late December and January, followed by an extraordinarily mild February and a colder March – but with significant protective snow cover. That makes it even more important to scout early and identify any problems from winterkill to snow mold, barley yellow dwarf virus, salt damage, frost injury or even Pythium.
Pythium, for example, will not kill plants outright, but rather colonize roots and cause uneven crop growth throughout the field. Winterkill tends to encompass and destroy larger, more general areas of the field and impacts plants that are left unprotected by snow cover.
Kansas wheat has already broken dormancy and is beginning to grow rapidly, making problem areas of the field obvious.
Syngenta experts recommend planting varieties with strong winter hardiness traits and using a seed treatment program will help protect plants from as many adverse effects as possible, including using a fungicide such as its Vibrance brand to provide early protection against the stress from disease as well as providing good stand strength to help the crop survive the cold months.
In addition to variety selection and seed treatments, growers can also employ other cultural practices to help increase wheat yields. Using a no-till or reduced tillage production system can be beneficial as standing stubble helps catch snow and insulate the crop, ensuring protection from low temperatures.