NDSU Soil Fertility Recommendation Updates A to Z

Transcription

1 NDSU Soil Fertility Recommendation Updates A to Z 22 nd Soil and Soil Water Workshop January 17, 2017, Fargo, ND David Franzen, PhD Professor Soil Science NDSU Extension Soil Specialist Fargo, ND

2 Outline- Main changes- No yield-based nutrient rate formulas (except for one) Greater science depth in narratives Potassium for several crops based on clay chemistry Most circulars are web-only publications

3 Outline (continued) The crops- Alfalfa Alsike, Birdsfoot trefoil, red clover, sweet clover Barley Buckwheat Canola Corn Dry bean Flax Forage grasses (in SF-882 only) Millet (in SF-882 only) Oats (in SF-882 only) Pea (Field pea) Lentil, Chickpea Potato Spring wheat/durum Sugar beet Winter wheat Zucchini

4 Yield and N rate are independent between fields. First indicated from work with active-optical sensors at Oklahoma State University Implied in the Return to N economic production functions used by NDSU and other mid-west states beginning in 2005

5 Sawyer and Nafziger, Return to N model- Integrates yield response to N with economics of the application. Recommendations are not necessarily linked to a yield goal. Assumes the grower is going for as much yield as economically practical. Categories known to affect yield are treated separately.

6 Yield, lbs per acre 4500 Eastern ND Sunflower Yield, y = x x R² = Total Known Available N, lbs per acre

7 Why is the aggregated relationship of yield and available N so diffuse, when the relationships within sites are so highly related?

8 Yield Example-Combining all sites with actual yield at N rate looks like this Total known available N

9 Yield When it really looks like this- Total known available N

10 To get a better idea of what the data look like without showing all the curves is to Normalize the data- putting it all in the same scale For example- A sunflower site with high yield 4,000 lb/acre, divide all yields by 4,000, and we end up with values from 0 to 1 A sunflower site with high yield 1,800 lb/acre, divide all yields by 1,800, and we end up with values from 0 to 1 A sunflower site with high yield 2,500 lb/acre, divide all yields by 2,500, and we end up with values from 0 to 1

11 Normalized Yield Normalizing yields at all sites ends up looking like this Total known available N

12 Normalized Yield If N rate and Yield were related between sites, the graphs would look like this after they were normalized Total known available N

13 Normalized Yield Within Site Wheat Yield, bushels per acre Western ND Conventional Till wheat sites raw yields y = x x r² = Total Known Available N, pounds per acre Western ND Conventional Till wheat sites, normalized yields y = -2E-05x x r² = Total Known Available N, pounds per acre

14 Normalized Wheat Yields Within Sites Wheat Yield, bushels per acre Western ND No-Till wheat sites raw yields y = x x r² = Total Known Available N, pounds per acre Western ND No-Till wheat sites normalized yields y = -1E-05x x r² = Total Known Available N, pounds per acre

15 Corn Yield Normalized Within Site Corn Yield, bushels per acre Eastern ND high-clay, Conventional Till, corn sites raw yields y = x x r² = Total Known Available N, pounds per acre Eastern ND high-clay, Conventional Till, corn sites normalized yields y = -6E-06x x r² = Total Known Available N, pounds per acre

16 Normalized Corn Yield Within Site Corn Yield, bushels per acre Eastern ND no-till, corn sites raw yields y = x x r² = Total Known Available N, pounds per acre Eastern ND no-till, corn sites normalized yields y = -5E-05x x r² = Total Known Available N, pounds per acre

17 Sunflower Yield Normalized Within Site Sunflower Yield, pounds per acre y = x x r² = Total Known Available N, pounds per acre Western ND no-till, sunflower sites raw yields Western ND no-till, sunflower sites normalized yields y = -5E-06x x r² = Total Known Available N, pounds per acre

18 Normalized Yield Sunflower Yield, pounds per acre Eastern ND Conventional Till, sunflower sites raw yields y = x x R² = Total Known Available N, pounds per acre Eastern ND Conventional Till sunflower sites normalized yields y = -4E-06x x R² = Total Known Available N, pounds per acre

19 The increased r 2 of the relationship between yield and available N with normalizing yield within site is only possible if the cloud of data in the original aggregated yield/ available N regression was really a series of reasonably parallel quadratic curves that lay on top of each other depending on the productivity of the site. These data and those of others analyzing similar modern data indicate that use of yield-based N rate formulas should cease, and people should recognize that a profitable N rate in a lower yield environment is similar to the N rate in a higher yield environment.

20 Low yield environmentusually drier (sometimes excessive wetness) Lower N use efficiency and crop uptake Less N mineralization High yield environment- Moisture near ideal- not too wet or too dry Higher N use efficiency and crop uptake Greater N mineralization Net result is that rate to produce economic max yield is similar in both environments.

21 All new fertilizer recommendation values will not be based on a yield-based formula. The recommendations will be relative yield-based. Wherever possible, regional and soil differences that result in a different relationship between nutrient and yield will be incorporated into the recommendations.

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26 There is a new phone app for Android phones for the 3 N calculators. Go to app store and search for North Dakota Crop Nitrogen Calculator and follow the instructions. It s free to download. We also have an app for Androids and Iphones- Go to the Iphone or Android app store and look up North Dakota Crop Nitrogen Calculator, then follow instructions.

27 Yield-Goal RIP

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29 Alfalfa SF-1863 Highlights S/I ratio >3.5, 200 ppm S/I ratio <3.5, 150 ppm Removal rates of K2O only for soils at, near or below critical level. Removal rates of P2O5 recommended. S encouraged.

30 Barley SF-723 Highlights Separate recommendations for malting and feed, western region and eastern region No yield-based formulas No-till credits for N rates

31 Buckwheat SF-724 Highlights No yield-based formulas P credit for subsequent crops provided

32 Canola SF-1122 Highlights No yield-based formulas Recommendations for western and eastern North Dakota S nutrition stressed

33 Clovers- SF 1865 Highlights- Soil ph > 6 Inoculation Removal rates of P2O5 recommended Critical level of K 150 ppm

34 Dry Beans- SF 720 Highlights- No yield-based formulas Except- high yielding irrigated (example-4,000 lb potential navies) Probably less than 1,000 acres total in North Dakota in any given year. The only Exception to yield-based formulas

35 Flax - SF 717 Highlights- No yield-based formulas No P recommended

36 Field pea, Lentil, Chickpea - SF 725 Highlights- Specific ph ranges for each crop Inoculation P recommendations no yield-based formulas Differences noted in response of crops to P and K

37 Potato- SF 715 Highlights- Recommendations not yield based Recommendations are cultivar/cultivar-type-based Recommendations consider harvest timing Potassium recommendations are based on clay-chemistry Joint publication with significant input from Carl Rosen, U of MN and Andy Robinson, NDSU

38 Potato- SF 715 Highlights- Recommendations not yield based Recommendations are cultivar/cultivar-type-based Recommendations consider harvest timing Potassium recommendations are based on clay-chemistry Joint publication with significant input from Carl Rosen, U of MN and Andy Robinson, NDSU

39 Spring wheat/durum - SF 712 Highlights- Recommendations not yield based Yield categories high, medium, low due to economic considerations P/K recommendations are not yield-based K recommendations increased to 150 ppm in S/I ratio >3.5 soils 100 ppm of S/I < 3.5

40 Winter wheat - SF 1448 Highlights- Recommendations not yield based N rates reduced in Langdon area K recommendations increased to 150 ppm in S/I ratio >3.5 soils 100 ppm of S/I < 3.5

41 Zucchini (just kidding, sort of) Highlights- Put on plenty of fertilizer Watch out for stem borers

42 Most of the revision are already available on line. The remaining revisions should be posted within 30 days.