Consider wheat in irrigated crop rotation
March 1, 2010
More farmers in the irrigated North Platte Valley ought to consider fitting winter wheat into their crop rotation, says Drew Lyon, Dryland Cropping Systems Specialist at the University of Nebraska Panhandle Research and Extension Center.
The vast majority of winter wheat acres in the Panhandle and elsewhere in Nebraska are grown under dryland, also known as rain-fed, conditions. Irrigation is not used to supplement precipitation.
Lyon said there was almost no irrigated winter wheat in the North Platte Valley when he arrived at the Panhandle Center in 1990. Today it is more common. Lyon listed several reasons that winter wheat fits well in an irrigated crop rotation.
There are several agronomic advantages.
The period when winter wheat needs the most water – the flowering and early grain-fill stage – coincides with the time of year when western Nebraska normally receives the most rain, May and June. So winter wheat will usually produce a crop when irrigation is limited. Most of the groundwater-irrigated land in the Panhandle will be subject to allocations of 14 to 16 inches of water for at least the next several years.
Winter wheat also can adapt to varying amounts of precipitation.
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“It has the ability to adjust to what Mother Nature provides,” Lyon said. Wheat has a lot of ways to make grain, and will provide at least half a crop even in the worst years. It also works well in rotation with other crops, Lyon says, because its peak water need falls earlier than most summer crops now grown in irrigated rotations.
During the growing season, winter wheat is very competitive with warm-season weeds. By the time these weeds come on, winter wheat already has developed enough of a canopy to block sunlight from reaching the weeds.
Introducing wheat into more-traditional irrigated crop rotations is advantageous with farmers’ existing schedules and workloads, Lyon says.
Winter wheat can spread the workload for producers of irrigated row crops. It is planted in September, following dry bean harvest.
Winter wheat also will fit into double-crop and relay-crop rotation systems. Under irrigated conditions, a forage crop can be planted following wheat harvest in July, enabling a farmer to produce two crops in one year.
Converting the traditional three-year crop rotation (dry beans-sugarbeets-corn) into a four-year rotation by adding winter wheat also has advantages. Because sugarbeets are susceptible to soil-borne disease, it’s good to allow an additional year between one sugarbeet crop and the next.
Residue management is another advantage. Winter wheat produces a good amount of useful and resilient crop residue. Many farmers have begun harvesting wheat with stripper headers on combines, which remove only the heads and leave behind the entire plant. This stubble has a higher silhouette factor than that of other crops, better protecting the soil from wind erosion. During the winter, it is effective in trapping snow and thus increasing soil moisture.
For producers considering adding wheat to their irrigated rotation, late July or early August is the time to think about which variety is best, Lyon said. UNL offers on-line resources to help in decision-making, including the wheat section at cropwatch.unl.edu. One of the on-line tools there is the Virtual Wheat Variety Tour.