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Fertilization Trends: Northern Plains Perspective February 2011 Jason Hanson is a regional agronomist with Winfield Solutions. Based at Webster, N.D., he works with sunflower and other crops throughout the North Dakota and northwest Minnesota production region. The Sunflower: Does some fertilization of upcoming sunflower ground in your area occur in the fall, or has it been almost exclusively spring-applied in recent years? Hanson: From the questions I field, there seems to be more fertility getting put on in the spring. More growers are putting on nitrogen and phosphorus for sure in the spring either as a one-pass or trying to band as much of their needs as they can. The weather cycle seems to be pushing growers toward more spring applications, as it is taking most of the fall just to get the harvest done. How much at-planting and/or sidedressing goes on in sunflower? There is a trend toward more starter or 2x2 applications. First, its more efficient; and second, its just showing more-consistent results. With fertilizer getting into the current price ranges, growers are just trying to use all their assets to maintain costs. A lot of sunflower these days is produced under a minimum-till or no-till system. How has that impacted fertilizer application timing and methodology, as compared to conventional flowers? Equipment has really driven this. As far as the no-till impact, the use of pre-emergence herbicides like the Spartan brands has been important, as is the improved ability (equipment) to place products. That spills over into a lot of interest in products like Agrotain, ESN or NutriSphere N as urea (if used) and no-till issues with surface-applied urea. Regarding nitrogen (soil + applied), is the old rule of 5 Lbs N Per 100 Lbs Yield Goal still a valid one to follow? We conducted a tissue sampling program this past year called NutriSolutions, which is an attempt at getting dealers to do a planned season-long nutrition program. What I saw in my area is that we are doing a very good job of supplying N to sunflower. That nutrient is not an issue. Most to all of it was based off the 5 lbs/100 lbs yield goal, so I think that is very adequate. Do most growers adequately test for and apply phosphorus and potassium as needed, or do these two nutrients tend to get underemphasized? I believe they adequately test for both nutrients. I know there isnt much to any potash put on, and phosphorus is getting applied mainly in starters. There are some deficiencies showing up on tissue samples with P, but a lot more with K especially later in the season. Do you encounter any micronutrient deficiencies in your area? Are there situations where including a micronutrient application would pay? The NutriSolutions tool showed a couple things with respect to secondary and micronutrients. One was that calcium was probably the largest deficient nutrient. Another micro that did not show up but one that some folks pay attention to was boron. It would appear that sunflower doesnt have an issue with extracting boron from North Dakota soils. But zinc did show up as somewhat low or deficient, suggesting that maybe theres more work to be done looking at zinc either in a starter or foliar application. From my experience this past year, it would appear that timing would play a huge part in making micronutrient applications effective. Most treatments that we put on were later in the season, and the effectiveness just wasnt there. Id also say that any spring that gives us cool, wet conditions would be where we have the best chance of seeing a response. Nutrient Levels 2010: A Central North Dakota Sampling This past year, Winfield Solutions, through its NutriSolutions program, tissue sampled 72 sunflower fields in central North Dakota. Samples were taken at three plant growth stages: (1) two- to four-leaf; (2) four- to 10-leaf; (3) immature bud stage. The general levels of select macro, secondary and micronutrients present in the analyzed samples were as follows: Nitrogen Excessive 54 samples Adequate 18 samples Low none Deficient none Phosphorus Excessive 33 samples Adequate 28 samples Low 3 samples Deficient 8 samples Potassium Excessive 8 samples Adequate 35 samples Low 7 samples Deficient 22 samples Calcium Excessive none Adequate 21 samples Low 18 samples Deficient 33 samples Sulfur Excessive 11 samples Adequate 45 samples Low 6 samples Deficient 10 samples Boron Excessive 50 samples Adequate 16 samples Low none Deficient 6 samples Zinc Excessive none Adequate 46 samples Low 12 samples Deficient 14 samples Manganese Excessive 15 samples Adequate 56 samples Low none Deficient 1 sample - Don Lilleboe
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