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The Grain Growing Classroom Five Fundamentals to Boost Wheat Yield By 10 Bushels By Tracy Sayler Which is a more obtainable New Year’s resolution – gaining 10 bushels from your next wheat crop or losing 10 pounds from your waistline? Either might be easier said then done, although on paper it comes down to simple equations for both. To lose the spare tire, it’s a matter of fewer calories in, more calories out. And NDSU extension agronomist Joel Ransom says that gaining that extra 10 bushels of wheat per acre comes down to this: Genotype x Management x Environment = Yield. Prepare and manage for increased yield before the growing season, do a good job of protecting yield potential during the growing season, and with cooperation from Mother Nature, the extra $40/ac in yield (assuming a $4/bu selling price) is quite attainable. The benefit to an adequate crop rotation is a given – wheat almost always yields better following a broadleaf crop rather than wheat or another grass. In a past 8-year study at Fargo by NDSU that looked at the effect of previous crop on wheat yields, wheat following sunflower outyielded wheat on wheat by an average of 9 bushels, and wheat after soybeans outyielded wheat-wheat by 14 bushels. Tillage is another irrefutable factor. In North Dakota, about 5 inches of water is needed to produce some kind of a crop, and each additional inch of moisture translates into about 2.5-3 bu/acre more wheat. Considering that each disc or chisel operation results in about a 0.5” moisture loss, the soil moisture (and fuel) savings of no-till add up. Here are five more fundamentals for producing that extra 10 bushels of wheat: 1) Seed varieties with high, stable yield. Select highest yielding varieties using replicated yield trial data for locations near your farm, and use multiple years and multiple locations when available. Select those that are consistently high yielding in a range of environments. If planting several varieties, choose diversity in heading date to spread disease risk and to help with the combining schedule. If planting a single variety, choose a consistent performer. Consider Freyr or Glenn for scab tolerance, says Ransom. Briggs, Howard , Steele-ND, Granger and Knudson are all good choices for yield; Glenn for high protein and test weight; and Briggs for earlier heading. If growing a single variety or with limited wheat area, consider Glenn or Freyr for a good mix of scab tolerance, yield and quality. Yield Performance Eastern ND Locations
Yield Performance Western ND Locations
2) Beat the heat. There will be exceptions when later planted spring wheat will do as well or even better than early planted wheat. But there’s no arguing that heat handicaps yield potential of this cool season crop. The main factor contributing to yield reduction is the potential of higher temperatures during the 4.0 to 5.5 leaf stage. This is the growth stage when the number of spikelets on the head is determined. The number of spikelets per spike decreases whenever the maximum day temperatures are above 63 F during this specific growth stage. If planting is delayed, increase your seeding rate by about 1% for each day planting is delayed up to a maximum rate of 1.6 million seeds/acre.
3) Feed the crop. Job one is knowing how much to feed, and you won’t know that without soil testing. The general nitrogen recommendation is Expected Yield x 2.5 – credits. The credits would be soil test nitrate at the 0-2 ft depth in lb/acre, and N credit expected after certain crops that do not appear on a fall or early spring nitrate soil test. Based on a reasonable yield goal, apply all nitrogen before planting (research in recent years has shown no benefit to split applications if N isn’t limiting). If during early crop development that it appears yield goal will be exceeded, apply additional N using streamer bars, and the earlier the better: a foliar application before the six-leaf stage is recommended to have the greatest chance of improving yield as well as protein. More attention is being given to economic optimum N rates. Cutting back on fertilizer N too much will affect yield and quality of most crops, but generally, yield response to N, and economic return compared to the cost of N, tends to level off at high N rates. Thus, establish reasonable yield goals based on past experiences and historical average yield. Use the historical yield average for a field and current fertilization recommendations to arrive at a base N rate. Then from the recommended total N rate, consider decreasing the rate by about 10% for 30 -cent N, and 15% for 40-cent N. If the decision is made to reduce rates, choose a higher protein variety that has a tendency to make grade no matter the conditions, taking other traits into consideration as well, including disease resistance, lodging, and yield consistency. Keep in mind that to be effective, in-season N needs rain to bring it to the roots. It takes at least ½” of rain to incorporate urea, so avoid application of urea on the surface in no-till fields, and in conventionally-tilled fields, till into the soil within 48 hours, unless it is so dry that granules remain intact. With anhydrous ammonia, keep application depth in mind. NH3 applied at least 4” deep is considered 100% efficient; 2-3” deep, 90% efficient. As well, the closer NH3 is applied to when the plant needs it, the greater the N use efficiency. In some years, there is little difference between a fall and spring application of anhydrous, while in some years, there may be as much as 20% difference. Canadian recommendations consider fall about 90% efficient as N applied in the spring. Add P with the seed: it is important for the wheat plant to have adequate phosphorus near the young root system early in its growth, as well as adequate P available in the entire rooting zone in order to feed the plant through kernel fill. Wheat plants make “decisions” concerning the number of tillers early in growth, and inadequate P will reduce tiller number and therefore reduce potential yield. Effect of AP Phosphate (~9 lbs P), Applied with Seed (8 Site Years)
Effect of N Timing on Wheat Yield in Various Experiments in ND, 2005
Effect of N Rate and Timing on Yield and Stem Numbers, Casselton, 2004
4) Establish a uniform, adequate stand. Use seed lots with at least 85% germination, and avoid seed lots from frost damaged spikes, with low falling numbers and very low protein. Use a seed treatment on wheat following wheat and with a questionable seed lot. Agronomists generally agree that an optimum spring wheat stand ranges between 28 to 32 plants per square foot (1 acre = 43,560 square feet; thus 28 to 32 plants per sq ft is about 1.2 million to nearly 1.4 million plants per acre. Thirty plants per square foot would be about 1.3 million plants per acre). A stand much below 1.2 million plants/ac may reduce yield potential, while a stand much over 1.4 million plants per acre may increase lodging potential. Varieties with strong straw strength can be seeded at higher rates, while varieties with less straw strength may need to be seeded at lower rates. If you plant early into good soil moisture, you can also reduce rates as you will take advantage of tillering. However, increase the seeding rate by 1 to 2 plants per square foot for every week planting is delayed past your early optimum seeding date. Under most conditions the optimum seeding depth is 1.5 to 2”. The objective of seed placement is to place the seed in a zone with ample moisture, but shallow enough that the crop can emerge quickly. 5) Protect yield. The timely control of just one weed can make a huge difference. Take wild oats, for instance. NDSU research shows that time of removal – that is, the point at which wild oats are eliminated as a competitor in the developing wheat crop – is critical. If wild oats emerge at the same time as the crop and are removed at the three-leaf stage, yield loss in wheat ranges from eight to 15%. If the wild oats are left until the five-leaf stage, yield losses rise to 25 to 35%. And if delayed until the flag leaf stage, wheat yields are cut by 65 to 75%. As well, scout for insects and respond to thresholds, and apply fungicides based on the likelihood of diseases. More growers are incorporating elements of precision ag in their efforts to boost yield and produce crops more efficiently: Auto steer, for example, for less skips and overlap of inputs and crop protection products. And GreenSeeker® technology, which is an integrated optical sensing and application system that measures crop status and variably applies the crop’s nitrogen requirements. With the GreenSeeker technology, yield potential for a crop is identified using a vegetative index known as NDVI (normalized difference vegetative index) and an environmental factor. N is then recommended based on yield potential and the responsiveness of the crop to additional nitrogen. Ultimately, the technology enables crop producers to apply the right amount of N at the right place and at the right time thereby optimizing yield and N input expense. There’s videos that explain the GreenSeeker technology online, at
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