K Nutrition in the NGP
Transcript of K Nutrition in the NGP
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Potassium Nutrition in theNorthern Great Plains
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Photo courtesy of Lyle Cowell, SWP
Outline: Potassium (K)Nutrition in the NorthernGreat 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
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What Is the Role of Kin Plants?
K activates enzyme reactions K controls water uptake and transpiration
K influences energy production in photosynthesis andrespiration
K supports photosynthate transport K fosters nitrate-nitrogen (N) uptake and protein
synthesis
K is required for starch synthesis in seeds
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Soil Water
K+
K+K+
K+
K+ K+ K+K+
K+ K+ K+K+Trapped K
K
K K
K
Soil Minerals(feldspar, mica)
SoilColloid
Soil Colloid
Soil Colloid
K
Unavailable (90 to 98%)
Slowly available (1 to 10%)
Readily
available
(0.1 to
2%)
Soil K
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Soil Testing Methodsfor K
Most soil tests for K are based on either an ammoniumacetate extraction or a similar extraction
In some regions with low CEC soils, K rates are oftenbased on the ratio of K relative to other bases, such as
Ca and Mg Ion exchange membranes which measure the soilsupply rate of K
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Median Ammonium AcetateEquivalent Soil Test K Levels,2005
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Median Ammonium AcetateEquivalent Soil Test KLevels, 2005
2005
ND
SK MBAB
MT
207
259 265
201
254
North American-wide
154 ppm
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K Deficient Areas onCanadian Prairies
May be deficient in K
May need K for irrigated crops
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Potassium Soil Test Ratingand Recommendations
Yield Soil test K, ppm
bu/A 0-40 41-80 81-120 121-160 161-200 201-250 251-750 +750
Fertilizer K recommendation, lb K2O/A
30 35 30 20 10 10 10 10 0
40 50 40 30 15 10 10 10 0
50 65 50 35 20 10 10 10 0
60 75 60 40 25 10 10 10 0
70 90 70 50 30 10 10 10 0
Wheat K2O 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:
Wh t A th K
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What Are the KRequirements of Cropsthroughout the Season?
Photo courtesy of Lyle Cowell
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K Uptake of Wheat Duringthe Growing Season
Jacobsen et al., 1992 (graphic from Korb et al., 2002)
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Crop Uptake of K
K uptake in
Crop Yield/A total crop, lb K2O/A
Wheat 40 bu 80 (19)*
Canola 35 bu 89 (20)Peas 50 bu 150 (39)
Barley silage 4.5 tons 132
Alfalfa 3 tons 180
*K removed in grain in parenthesis.
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Potassium DeficiencySymptoms in Barley
11
38
49
58
0 60 120 2400
10
20
30
40
50
60
Barley
grainyield
,bu/A
K2O rate in lb/A
i d i h
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Potassium Budget in theNorthern Great PlainsRegion, 2000-2001
-544-5571352609North Dakota
-301-310942352Montana
-195-2404592332Manitoba
-538-5814359640Saskatchewan
-343-479136128607Alberta
--------------------- K2O, million lb ---------------------
F+M-RF-R(M)(F)(R)
BalanceRecoverable
Manure
Fertilizer
Applied
Crop
Removal
State or
Province
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K Deficiency Symptoms
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K Deficiency Symptoms
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Plant Tissue K Guidelines forCrops An Example
3.9 4.72.5 3.81.8 2.4
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Crop Responses to K
While many northern Great Plains soils have abundantK, 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
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Barley Response to Soil KLevels and Fertilizer K2O
N and P added to soil test recommendation D. Walker, Lacombe, AB
Soil K 50-75 ppm/A
Soil K 75-100 ppm/A
Soil K 25-50 ppm/A
010
20
30
4050
60
70
80
0 12 24
Added K, lbs K2O/A added to seed row
%
Gra
inYield
Incre
ase
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Barley, Wheat, and CanolaResponse to K
N and P added to soil test recommendation Henry and Halstead, 1968
72 ppm K/A
33 ppm K/A
30 ppm K/A
50 ppm K/A
36 ppm K/A
Canola
Wheat
Barley
010
20
30
40
50
60
70
0 100 200 400
Added K (lb K 2O/A Broadcast + Incorp)
Grainyield,
bu/A
K Benefits Crop Growth and
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K Benefits Crop Growth andYield Longevity of AlfalfaStands
K increases carbohydrate in the crown roots ofalfalfa during fall growth to increase
- Winter hardiness
- Early spring re-growth
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Manitoba - Soil K 116 ppm/A (0 to 6 in.)
100 lb K2O/yrNo K100
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7
0
20
40
60
80
S
tandd
ensity ,%
Plant counts in May as % of those the previous September
K Helps Reduce Winterkillin Alfalfa
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Crop Response onHigh K Soils
Yield increases often occur from potash applied on soilsnot 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
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Barley Response to Starter Kand Seeding Date
Dubbs, Montana State Univ.Soil K levels - High
April 6 May 6 June 3
7 bu
6 bu
3 bu
0
10
20
30
40
50
60
B
arley
Yield
(b
u/A)
Check
20 K2O
Crop Response to Added K
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Crop Response to Added Kin High K Soils in Montana(264 Sites)
36 Expts.
48 Expts.
33 Expts
97 Expts.
0 20 40 60 80
Winter Wheat
Spring Wheat
Feed Barley
Malt Barley (irr.)
Alfalfa
Corn Silage
Potatoes (irr.)
10 Expts.
22Expts.
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 (1967-1979)Skogley & Haby 1981
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Barley, oats, and rape 1968-74
Crop Response to Added K inAlberta (548 sites)
Exch. K Total Responsive Average
ppm/A sites sites,% Resp., cwt/A
0 - 50 37 70 6.1
51 - 100 132 73 4.8
101 - 150 115 55 2.5
151 - 200 100 52 2.4
201 - 300 99 46 2.7
301 - 400 37 43 2.4
> 400 28 21 1.9
Lopetinsky 1977
Frequency Distribution
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Frequency Distributionof Soil K on a 220 x 220 ft.Grid at Mundare, AB
Penny et al., 1996
Mean = 135 ppm
Mode = 108 ppm
05
10
15
20
25
30
35
Frequ
ency
(%)
59-101 101-
143
143-
185
185-
227
227-
269
269-
311
Soil K (ppm)
hl id i l
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Chloride---An EssentialPlant Nutrient
The deficiency of Cl in the soil can account for cropresponses to KCl application.
Earliest report of Cl crop response ... table salt (NaCl)in mid 1800s
Recognized as an essential micronutrient since the1950s
Research in the late 1970s revealed insufficient levelsin many areas
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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 thegrain 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
Ph i l i l L f S t
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Physiological Leaf Spot onKestrel Winter Wheat
No ChlorideNo Chloride ChlorideChloride
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Chloride May ImproveCrop Yields
~ 200 university trials in KS, MN, MT, ND, SD, MB,and SK have evaluated Cl response in wheat andbarley
Included non-responsive and high Cl sites
Significant yield response in 48% of trials Average yield response of 5 bu/A
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Yield Boost from ChlorideDepends on Wheat Variety
-6
-4
-2
0
2
4
6
8
1012
Yieldrespo
ns
e,
bu/A
Barrie Cora Grandin Karma Kyle
1996 1997 1998
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Fertilizer K Management
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Once in the soil,
all fertilizersources are thesame form as
found in the soil(K+). This is theform taken up by
plants.
K+
KClKCl KK22SOSO44
Wh t H t
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What Happens toFertilizer 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 SlowlyAvailable K
Unavailable K
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Fertilizer K Sources
Source Analysis
Potassium chloride, KCl 0-0-60 (62)
Potassium sulfate, K2SO
40-0-50 - 17
Potassium nitrate, KNO3
13-0-44
Potassium-magnesium sulfate,
K2SO
4
.2MgSO4
0-0-22-22-11
Potassium thiosulfate, K2S
2O
30-0-25-17
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Fertilizer K Placement
l Cl
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Barley Response to KClPlacement and Rate
N and P added to soil test recommendation SIP Soil Fertility Rpt, 1968
Broadcast
Side band
Seed row
0
5
10
15
20
25
30
0 15 30 60 90 120 150 180 240
lb K2O/A
GrainYieldI n
creas
e(bu/A)
Safe Rates of Seed Ro K
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Safe Rates of Seed Row Kapplication (Saskatchewan)
Seed row application of K2O should not exceed
(1 in. spread, 6 to 7 in. rows): Cereals 50 lb K2O/A
Canola 20 lb K2O/A
Dry pea 15 lb K2O/A Combined P2O5 and K2O in the seed row should also not
exceed the recommended safe rates for K2O alone
Source: Saskatchewan Agriculture and Food
Potassium Does Not Cause
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Potassium Does Not CauseRoots 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 (%)
0 20 40 60 80 100Proportio
nofrootsobserv
edinKsolution
(%)
0
20
40
60
80
100 Corn 17 days old
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Be Sure and
Use SoilTesting toMonitor Soil K
Supplies
Summary
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SummaryK Nutrition in the NorthernGreat 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
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International Plant Nutrition Institute655 Engineering Drive, Suite 110Norcross, GA 30092-2604Phone: 770-447-0335; Fax: 770-448-0439
www.ipni.net