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Potassium Nutrition in the Northern Great Plains.

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Presentation on theme: "Potassium Nutrition in the Northern Great Plains."— Presentation transcript:

1 Potassium Nutrition in the Northern Great Plains

2 Photo courtesy of Lyle Cowell, SWP Outline: Potassium (K) Nutrition in the Northern Great Plains Role of K in crop production Soil K and soil test levels Crop uptake of K K deficiencies Crop responses to K Chloride (Cl) response Fertilizer K

3 What Is the Role of K in Plants? K activates enzyme reactions K controls water uptake and transpiration K influences energy production in photosynthesis and respiration K supports photosynthate transport K fosters nitrate-nitrogen (N) uptake and protein synthesis K is required for starch synthesis in seeds

4 Soil Water K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ Trapped K K K K K Soil Minerals (feldspar, mica) Soil Colloid K Unavailable (90 to 98%) Slowly available (1 to 10%) Readily available (0.1 to 2%) Soil K

5 Soil Testing Methods for K Most soil tests for K are based on either an ammonium acetate extraction or a similar extraction In some regions with low CEC soils, K rates are often based on the ratio of K relative to other bases, such as Ca and Mg Ion exchange membranes which measure the soil supply rate of K

6 Median Ammonium Acetate Equivalent Soil Test K Levels, 2005

7 2005 ND SK MB AB MT North American-wide 154 ppm

8 K Deficient Areas on Canadian Prairies May be deficient in K May need K for irrigated crops

9 Potassium Soil Test Rating and Recommendations YieldSoil test K, ppm bu/A Fertilizer K recommendation, lb K 2 O/A Wheat K 2 O recommendations using band application (Agvise Labs) -Soil test recommendations vary among labs. -Most labs use a set of regional crop response data to develop fertilizer recommendations based on a K soil test. An example:

10 What Are the K Requirements of Crops throughout the Season? Photo courtesy of Lyle Cowell

11 K Uptake of Wheat During the Growing Season Jacobsen et al., 1992 (graphic from Korb et al., 2002)

12 Crop Uptake of K K uptake in Crop Yield/A total crop, lb K 2 O/A Wheat40 bu80 (19)* Canola35 bu89 (20) Peas50 bu150 (39) Barley silage4.5 tons132 Alfalfa3 tons180 *K removed in grain in parenthesis.

13 Potassium Deficiency Symptoms in Barley Barley grain yield, bu/A K 2 O rate in lb/A

14 Potassium Budget in the Northern Great Plains Region, North Dakota Montana Manitoba Saskatchewan Alberta K 2 O, million lb F+M-RF-R(M)(F)(R) BalanceRecoverable Manure Fertilizer Applied Crop Removal State or Province

15 K Deficiency Symptoms


17 Plant Tissue K Guidelines for Crops … An Example 3.9 – – – 2.4<1.7Alfalfa – top 6 in. 3.1 – – – 1.5<1.2Wheat – heading 2.5 – – – 1.9<1.4Wheat – boot 3.1 – – – 1.5<1.2Wheat – tillering HighSufficientLowDeficientCrop type -- stage % K in plant tissue Agvise Labs

18 Crop Responses to K While many northern Great Plains soils have abundant K, the region also has areas with very low soil K It is not uncommon to find areas of Saskatchewan and Alberta with soils testing 30 to 50 ppm K/A Crops respond to K application in these low K soils

19 Barley Response to Soil K Levels and Fertilizer K 2 O N and P added to soil test recommendationD. Walker, Lacombe, AB Soil K ppm/A Soil K ppm/A Soil K ppm/A Added K, lbs K 2 O/A added to seed row % Grain Yield Increase

20 Barley, Wheat, and Canola Response to K N and P added to soil test recommendation Henry and Halstead, ppm K/A 33 ppm K/A 30 ppm K/A 50 ppm K/A 36 ppm K/A Canola Wheat Barley Added K (lb K 2 O/A Broadcast + Incorp) Grain yield, bu/A

21 K Benefits Crop Growth and Yield Longevity of Alfalfa Stands K increases carbohydrate in the crown roots of alfalfa during fall growth to increase - Winter hardiness - Early spring re-growth

22 Manitoba - Soil K 116 ppm/A (0 to 6 in.) 100 lb K 2 O/yr No K 100 Year 1Year 2Year 3Year 4Year 5Year 6Year Stand density, % Plant counts in May as % of those the previous September K Helps Reduce Winterkill in Alfalfa

23 Crop Response on High K Soils Yield increases often occur from potash applied on soils not deficient in K. Why? K responses as a result of: - Cold soils in the spring (slow root growth and nutrient uptake) - Dry soils (droughty conditions reduce K diffusion) - Field (landscape) variability - Cl ion (Cl - ) response

24 Barley Response to Starter K and Seeding Date Dubbs, Montana State Univ.Soil K levels - High April 6May 6 June 3 7 bu 6 bu 3 bu Barley Yield (bu/A) Check 20 K2O

25 Crop Response to Added K in High K Soils in Montana (264 Sites) 36 Expts. 48 Expts. 33 Expts 97 Expts Winter Wheat Spring Wheat Feed Barley Malt Barley (irr.) Alfalfa Corn Silage Potatoes (irr.) 10 Expts. 22 Expts. 18 Expts. 5.5 bu/A 4.8 bu/A 3.9 bu/A 9.2 bu/A 0.35 t/A 2.8 t/A 25 cwt/A Frequency of response, % Each crop represents 2 to 8 cropping years Soils testing > 600 ppm ( ) Skogley & Haby 1981

26 Barley, oats, and rape – Crop Response to Added K in Alberta (548 sites) Exch. KTotalResponsiveAverage ppm/Asitessites,%Resp., cwt/A > Lopetinsky 1977

27 Frequency Distribution of Soil K on a 220 x 220 ft. Grid at Mundare, AB Penny et al., 1996 Mean = 135 ppm Mode = 108 ppm Frequency (%) Soil K (ppm)

28 Chloride---An Essential Plant Nutrient The deficiency of Cl in the soil can account for crop responses to KCl application. Earliest report of Cl crop response... table salt (NaCl) in mid 1800s Recognized as an essential micronutrient since the 1950s Research in the late 1970s revealed insufficient levels in many areas

29 Chloride has been shown to have an effect on: –Root rot and foliar diseases in cereal crops –Seed weight at harvest, especially barley, by extending the grain filling period –Reducing physiological leaf spot in cereal crops on fields where soil Cl is less than 10 lb/A (24 in. depth) –Increasing crop yields Crop Responses to Chloride

30 Physiological Leaf Spot on Kestrel Winter Wheat No Chloride Chloride

31 Chloride May Improve Crop Yields ~ 200 university trials in KS, MN, MT, ND, SD, MB, and SK have evaluated Cl response in wheat and barley –Included non-responsive and high Cl sites Significant yield response in 48% of trials Average yield response of 5 bu/A

32 Yield Boost from Chloride Depends on Wheat Variety

33 Fertilizer K Management

34 Once in the soil, all fertilizer sources are the same form as found in the soil (K + ). This is the form taken up by plants. K+K+ KCl K 2 SO 4

35 What Happens to Fertilizer K in the Soil? Absorbed by crop in year 1: –20 to 60% of applied K –Highest recovery on low K soils Slowly available K (future years): –Bulk of remaining K in most soil types –Future supply of K Available K Slowly Available K Unavailable K

36 Fertilizer K Sources SourceAnalysis Potassium chloride, KCl (62) Potassium sulfate, K 2 SO Potassium nitrate, KNO Potassium-magnesium sulfate, K 2 SO 4. 2MgSO Potassium thiosulfate, K 2 S 2 O

37 Fertilizer K Placement

38 Barley Response to KCl Placement and Rate N and P added to soil test recommendation SIP Soil Fertility Rpt, 1968 Broadcast Side band Seed row lb K 2 O/A Grain Yield Increase (bu/A)

39 Safe Rates of Seed Row K application (Saskatchewan) Seed row application of K 2 O should not exceed (1 in. spread, 6 to 7 in. rows): –Cereals – 50 lb K 2 O/A –Canola – 20 lb K 2 O/A –Dry pea – 15 lb K 2 O/A Combined P 2 O 5 and K 2 O in the seed row should also not exceed the recommended safe rates for K 2 O alone Source: Saskatchewan Agriculture and Food

40 Potassium Does Not Cause Roots to Proliferate Split-root experiment Percent of the total root system on the side with K was the same as that on the side without K Effects of K on root growth may not be localized as is found with P Classen and Barber, 1977 Proportion of roots expected for no K effect (%) Proportion of roots observed in K solution (%) Corn 17 days old

41 Be Sure and Use Soil Testing to Monitor Soil K Supplies

42 Summary— K Nutrition in the Northern Great Plains K nutrition is critical to crop production Most northern Great Plains soils are high in K, allowing for a net removal of soil K each year Crops take up as much K as N during growth, with only a small proportion removed in grain Where deficient, crop response to K is greatest for barley, followed by wheat and canola Crop responses to muriate of potash (KCl) can be a Cl response

43 International Plant Nutrition Institute 655 Engineering Drive, Suite 110 Norcross, GA Phone: ; Fax: Reference #06111

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