The Value of Wheat in a Crop Rotation August 31, 2016
With low winter wheat prices, should crop producers abandon wheat as part of their cropping system? Growers across western Nebraska often say they produce winter wheat so they can grow higher value crops such as dryland corn, sunflowers, or grain sorghum. Does that statement still hold true with corn prices higher than winter wheat prices?
What are the benefits of producing a good winter wheat crop? First, properly managed winter wheat residue is very effective in reducing the E (evaporation) in ET (evapotranspiration). It can reduce evaporation from 35% of the crop water use to 15%. The winter wheat residue is also very effective in breaking up raindrops. Raindrop impact can result in fine soil particles consolidating on the surface to form a thin crust. Soil crusts can reduce infiltration rates up to 75%, resulting in erosion and water loss.
Good winter wheat residue also results in greater soil water. A 60 bu/ac winter wheat crop harvested with a stripper header had 72 inches plus (Figure 1) of soil water or about 9 inches of plant available water by April 12, 2016 at the Henry J. Stumpf International Wheat Center near Grant. In contrast, Wheat Center plots that were cut with a platform header at about 10 inches high and did not have the residue properly spread only had 26 inches of soil water by April 12, 2016, or about 4.3 inches of plant available water (Figure 2). The 4.7-inch difference in soil water in this example is estimated to increase corn or grain sorghum by about 56 bu/ac in years with average precipitation during the growing season for this area. The soil at the Wheat Center changes to sand at about 3 feet, hence the reduced plant-available water.
Even in dry years, it is possible to produce 70 bu/ac corn or grain sorghum if you had a good winter wheat crop the previous year and managed the crop residue properly.
Additional benefits of having winter wheat in a crop rotation are timely utilization of available water, reduced soil erosion, and building organic matter in the soil. Also, a longer rotation including wheat will aid weed suppression and help better manage weeds, insects, and diseases. Including winter wheat also helps distribute labor requirements and, because of crop diversification, reduces risk.
Although the current price of winter wheat does not provide much incentive to grow the crop, the benefits of wheat in a crop rotation, especially in a water-limited environment, are numerous. Producers need to look beyond the price of winter wheat and consider the synergistic and additive value of winter wheat on other crops in their rotation. Without wheat residue to protect the soil moisture for other crops, yields of those higher value crops will fall. Understanding how much support wheat gives to the yields of other crops in a rotation allows us to put a more accurate value on the wheat crop.