Mineral Nutrition for

Vegetable Crops
Liz Maynard, Dept. of Hort and LA, Purdue

January 5, 2017 Illiana Vegetable Growers Symposium

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 70
$$ Fig. 2. Black rot at EcoHio and LIFE
Farms. a. Soil amendment effects.
60
Fertilizer Cost a.
15-50% 50 Foliar
Black Rot
preharvest 40 Sympto
ms (%)
variable costs
30
3 – 10% FT
Gross Returns20 NS
VD
10
VM
0
6/25 7/5 7/15 7/25
Date
Healthy Soil
Physical
– Structure
– Pore Space
– Pore Sizes
Biological
– Arthropods
– Earthworms
– Microbes
Chemical
– pH
– Mineral nutrients
– Other elements and compounds

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Essential Elements for Plants
Macronutrients Micronutrients
Nitrogen N Copper Cu
Phosphorus P Iron Fe
Potassium K Manganese Mn
Molybdenum Mo
Calcium Ca Nickel Ni
Magnesium Mg Zinc Zn
Sulfur S Boron B
Chlorine Cl

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 Inputs:
Fertilizers • Organic Matter
Nitrogen Fixation

NH4+ NO3- soil solution

H2PO42- Ca2+
H+ Ca++
K+
Mg2+ Fe – – Ca++
SO4- K+ –
– H+
H+ –

– – –– –
Ca++
H+ K+ H+
H+
soil organic matter
cation exchange sites

soil minerals
Losses: Leaching • Plant Removal
Erosion • Denitrification E. Maynard
Purdue Univ.
 Soil Test for pH and
Plant Nutrients

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pH 6.0 - 6.8

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 Adapted from Warncke et al. 2004 N (Lb/1000 sq. ft.)
Crop N (lb./1000 sq. ft.) 0 1 2 3 4 5

Beans, snap 0.9 Beans, snap

Peas 0.9 Peas

100 lb. /A
140 lb. /A
Asparagus, established 1.1 Asparagus, established
Radish 1.1 Radish
Sweet potato 1.4 Sweet potato
Cucumber, slicers 1.8 Cucumber, slicers
Pumpkin 1.8 Pumpkin
Squash, hard 1.8 Squash, hard
Squash, summer 1.8 Squash, summer
Zucchini 1.8 Zucchini
Turnip 2.1 Turnip
Muskmelon 2.3 Muskmelon
Watermelon 2.3 Watermelon
Beets, red 2.3 Beets, red
Greens, leafy 2.3 Greens, leafy
Rutabaga 2.3 Rutabaga
Swiss chard 2.3 Swiss chard
Lettuce, leaf 2.3 Lettuce, leaf
Carrots, fresh market 2.3 Carrots, fresh market
Parsley 2.3 Parsley
Parsnip 2.3 Parsnip
Pepper, bell 2.3 Pepper, bell
Eggplant 2.8 Eggplant
Tomato, fresh market 2.8 Tomato, fresh market
Sweet corn 2.8 Sweet corn
Cabbage, Chinese 2.8 Cabbage, Chinese
Pak choi 2.8 Pak choi
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Onion, green 3.0 Onion, green
Broccoli 3.2 Broccoli
Brussels sprouts 3.2 Brussels sprouts
Cabbage, fresh market 3.2 Cabbage, fresh market
Cauliflower 3.2 Cauliflower
Kohlrabi 3.2 Kohlrabi
Lettuce, head 3.2 Lettuce, head
Lettuce, romaine 3.2 Lettuce, romaine
Nitrogen Recommendations for Vegetable Crops

Market garden 3.2 Market garden

Celeriac 3.4 Celeriac
Leek 3.4 Leek
Spinach 3.9 Spinach
Potato 4.1
200 lb. /A

Potato
Onion, dry bulb 4.4 Onion, dry bulb
Celery, fresh market 4.6 Celery, fresh market
 N Credits: Useful for Estimating N Needed from Fertilizer
Previous Crop Nitrogen Credit
lb/A N
Alfalfa, established 40 + % stand
Clover, established 40 + 0.5 % stand
Wheat + Legume 30 + 0.5 % stand
Warncke et al. 2004

Soybeans 30

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N Credits: Useful for Estimating N Needed from Fertilizer
Cover Crops
• Need to know dry weight of cover crop/A and percent N
Managing Cover Crops Profitably: BUILDING SOIL FERTILITY AND TILTH
WITH COVER CROPS
www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition

Soil Organic Matter

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Presidedress Nitrate Test (PSNT)
Useful for estimating nitrogen supply during the growing season
Sample soil shortly before rapid crop growth and sidedressing or
topdressing
Dry sample quickly or freeze and send to soil analysis lab
Guidelines from the Northeast:
Sweet corn no sidedressing needed if NO3-N > 20-25 ppm in top 12 inches
Pumpkin, winter squash, cabbage, peppers: no sidedressing needed if NO3-
N > 25-30 ppm in top 12 inches
Reference: Using the Pre-Sidedress Soil Nitrate Test to Improve Nitrogen Management in Vegetable
Cropping Systems. Spargo, Mangan, and Howell, 2013. https://soiltest.umass.edu/fact-
sheets/using-pre-sidedress-soil-nitrate-test-improve-nitrogen-management-vegetable-cropping14
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Phosphorus (P)
Build-up: Amount based Soil Test P* Phosphorus
on soil test plus the (ppm) Application
maintenance amount < 35 Build-up
Maintenance: Amount
35 - 80 Maintenance
removed by harvested
portion of crop > 80 None needed
*Bray-Kurtz P1 extraction.

Warncke et al. 2004

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Adapted from Warncke et al. 2004

0
1
2
3
4
5

0.5
1.5
2.5
3.5
4.5
Watermelon
Rhubarb
Radish
Tomato, fresh market
Tomato, processing

P2O5 Removed (lb/ton)

Broccoli
Cucumber, slicers
Pumpkin
Swiss chard
Turnip
Pepper, banana
Pepper, bell
Pepper, hot
Cabbage, fresh market
Eggplant
Zucchini
Carrots, fresh market
Celery, fresh market
Greens, leafy
Lettuce, leaf
Muskmelon
Beets, red
Squash, hard
Squash, summer
Beans, snap
Sweet potato
Cauliflower
Onion, dry bulb
Onion, green
Potato
Spinach
P2O5 Removed in Harvested Vegetables (lb/ton)

Garlic
Market garden
Sweet corn
Brussels sprouts
Parsnip
Asparagus, established
0.25

Peas
Lb. / 100 lb.
Potassium (K) Soil K Potassium
Build-up: Amount based (ppm) Application
on soil test plus the
maintenance amount Cation Exchange
Capacity (meq/100g)
Maintenance: Amount
removed by harvested 4 16
portion of crop <85 <115 Build-up
85-135 115-165 Maintenance
>135 >165 None needed

Warncke et al. 2004

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 Adapted from Warncke et al. 2004

0
2
4
6
8
10
12
14
Watermelon
Cucumber, slicers
Turnip
Onion, dry bulb
Onion, green

K2O Removed (lb/ton)

Eggplant
Radish
Pepper, banana
Pepper, bell
Pepper, hot
Garlic
Market garden
Sweet corn
Greens, leafy
Zucchini
Squash, hard
Squash, summer
Cauliflower
Pumpkin
Cabbage, fresh market
Carrots, fresh market
Rhubarb
Tomato, fresh market
Tomato, processing
Beets, red
Lettuce, leaf
Parsnip
Swiss chard
Brussels sprouts
Asparagus, established
K2O Removed in Harvested Vegetables (lb/ton)

Peas
Broccoli
Muskmelon
Beans, snap
Celery, fresh market
Spinach
Potato
0.70

Sweet potato
Lb. / 100 lb.
Pumpkins MW Veg Prod Guide 2017 (ID-56) p. 104
Nitrogen:
– Preplant: 50
– Sidedress: 30-40
Total: 80-90 lb./A

Sidedressing N not needed if soil

organic matter is greater than 3%
and following a legume

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Pumpkins
Phosphorus
– 0 to 150 lb /A P2O5
depending on soil test Soil Test P Expected Yield (tons/A)
(ppm) 15 25
For this example: Recommended Lb. P2O5/A
36 lb./A P2O5 25 118 136
45 - 80 18 36
90 0 0

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Pumpkins
Potassium
Soil K Expected Yield (tons/A)
– 0 to 200 lb /A K2O
depending on soil test (ppm) 15 25
CEC-> 4 12 4 12
For this example: Recommended Lb. K2O/A
170 lb./A K2O
40 156 206 224 274
115 102 102 170 170
135 0 102 0 170
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Pumpkins. Option 1.
Preplant: Urea: 45-0-0 (N-P2O5-K2O)
– 36 lb./A N from 80 lb. urea (45-0-0) 36 lb./A divided by 0.45 = 80 lb./A
– 14 lb./A N and DAP: 18-46-0
– 36 lb. P2O5 from 78 lb. DAP banded 2x2 14 lb./A divided by 0.18 = 78 lb./A
– 170 lb./A K2O from 283 lb. KCl (0-0-60) 36 lb./A divided by 0.46 = 78 lb./A
Sidedress: KCl: 0-0-60
– 30 lb./A N from 10 gallons 28% UAN 170 lb./A divided by 0.60 = 283 lb./A
Formulas:
1. Lbs. nutrient per A divided by % nutrient in the UAN: 28-0-0, 10.65 lb./gal
fertilizer (written as a decimal, e.g. 10% = 0.10) = 30 lb./A divided by 0.28 = 107 lb.A
Lbs. fertilizer per A UAN
2. Lbs. fertilizer per A times % nutrient in the fertilizer 107 lb./10.65 lb./gal = 10 gal
(written as a decimal) = Lbs. nutrient per A

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Tomatoes MW Veg Prod Guide 2017 (ID-56) p. 125-126
Nitrogen:
– Preplant: 30
– Transplant starter:
– Sidedress: 60-80
Total: 100-120 lb./A

Reduce by credits from legumes

and soil organic matter greater than
3%

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Tomatoes
Phosphorus
– 0 to 240 lb /A P2O5
depending on soil test Soil Test P Expected Yield (tons/A)

For this example:

(ppm) 20 30
24 lb./A P2O5 Lb. P2O5/A
25 116 124
45 - 80 16 24
90 0 0

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Warncke et al. 2004 40
Tomatoes
Potassium
Soil K Expected Yield (tons/A)
– 0 to 300 lb /A K2O
depending on soil test (ppm) 20 30
CEC-> 4 12 4 12
For this example: Lb. K2O/A
210 lb./A K2O
40 194 244 264 300
115 140 140 210 210
135 0 140 0 210
Warncke et al. 2004
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 Acres or Linear Bed Feet?
Acres Linear Bed Feet (LBF)
175 ft. X 90 ft. = Beds on 5-ft
15,750 ft2 centers
175 ft. X 18
beds =
175 ft.

175 ft.
15,750 ft2/
43,560 ft2/A = 3,150 LBF
0.36 A

90 ft. 90 ft.

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 Fertilizer Rates per
Linear Bed Foot
Bed Fertilizer Rate (lb/A)
Spacing LBF/A 30 60 90 120 150 180 210
(ft.) Fertilizer Rate (lb./LBF)
3 14,520 0.0021 0.0041 0.0062 0.0083 0.0103 0.0124 0.0145
4 10,890 0.0028 0.0055 0.0083 0.0110 0.0138 0.0165 0.0193
5 8,712 0.0034 0.0069 0.0103 0.0138 0.0172 0.0207 0.0241
6 7,260 0.0041 0.0083 0.0124 0.0165 0.0207 0.0248 0.0289
8 5,445 0.0055 0.0110 0.0165 0.0220 0.0275 0.0331 0.0386
See pp. 16-17 of 2017 ID-56
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Tomatoes – Option 2. 1000 LBF Calculations for starter fertilizer
Nitrogen: Recommended rate is 48 fl.oz. 10-34-0 in 50
– Preplant: 3.4 lb N from 7.6 lb. urea. gal. solution, use 8 oz. per plant.
Broadcast or work into bed during formation. 1. How much 10-34-0 is needed?
– Transplant starter: 0.27 lb. N from 30 fl.oz. 10-34-0 Assume 500 plants X 8 fl.oz. solution per plant
– Fertigate: 8.0 lb. N = 31 gal. of solution needed for 1000 LBF
• 5.0 lb. N from Calcium nitrate, 32.4 lb. For 31 gal. of solution, use 31/48 =
30 fl.oz. 10-34-0.
–3.2 lb. CN per week for 10 weeks
• 3.0 lb. N from Potassium nitrate, 21.2 lb.
2. How much N and P2O5 is in the solution?
–2.1 lb. KN per week for 10 weeks 1 gallon 10-34-0 weighs 11.65 lb.
Total: 11.7 lb./1000 LBF 30 fl.oz. of 10-34-0 weighs (30/128)X11.65 =
Cost: $2.27 + $16.77 + $15.58= $34.62 2.7 lb.
10-34-0 is 10% N by weight and 34% P2O5
(does not include starter)
2.7 lb X 0.10 = 0.27 lb. N
2.7 lb. X 0.34 = 0.93 lb. P2O5
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Tomatoes – Option 2., cont. 1000 LBF
Phosphorus:
– Starter: 0.93 lb. P2O5 from 30 fl.oz. 10-34-0
Total: 0.93 lb./1000 LBF
Cost: $0.61
Potassium: N-P-K Total cost:
– Preplant: 9.75 lb K2O from 16.3 lb. potassium chloride $40.07
(0-0-60). Broadcast or work into bed during formation.
– Fertigate: 9.75 lb K2O from 21.2 lb. potassium nitrate
• 2.1 lb. KN per week for 10 weeks
Total: 19.5 lb./1000 LBF
Cost: $4.84 + $15.58 (already included in N cost)

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Tomatoes – Option 3. 1000 LBF
Nitrogen: If soil is high in
– Preplant: organic matter
• 4.4 lb. N from hairy vetch/rye cover crop, killed early May and there is a
• 3.4 lb. N from 48.6 lb. 13-0-0 organic fertilizer (assume 7% history of adding
available) organic soil
0.8 lb. N from 4 bushels (140 lb) compost 3-2-2 (assume
0.6% available)
amendments,
– Sidedress: 2.9 lb. N if needed 13-0-0 may not be
• from 41 lb. 13-0-0 needed
Total: 11.5 lb./1000 LBF
Cost for 13-0-0: $58
Prices for 13-0-0 from price paid in 2013 for bagged product.
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Tomatoes – Option 3., cont. 1000 LBF
Phosphorus:
– Preplant: 2.8 lb. from 4 bushels (140 lb.) compost (3-2-2)
Total: 2.8 lb./1000 LBF
Cost: ??
Potassium: Cost of bagged N and
K2O: $73 - $98
– Preplant:
• 2.8 lb K2O from 4 bushels (140 lb.) compost (3-2-2) Plus: cover crop seed,
compost
• 16.7 lb K2O from 33 lb. potassium sulfate (0-0-52)
Total: 19.5 lb./1000 LBF
Cost for potassium sulfate: $15 - $40
Prices for K S from wholesale supplier web site and price quote in 2014.
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Efficient Fertilizer Use
Close to time of crop use
In root zone of crop

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Foliar Fertilization

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Example Foliar Fertilization Rates from Product Labels
Nutrients Applied % of Tomato Crop Uptake†
Product Rate* Sprays* N P 2O 5 K 2O N P 2O 5 K 2O
N-P2O5-K2O lb/A no. lb/A
18-18-18 5-10 3-5 2.7-9 2.7-9 2.7-9 1.5 - 5 5.6 -19 0.8 - 3

20-5-5 3-10 5-10 3-20 0.75-5 0.75-5 1.6 - 11 1.6 - 10 0.2 - 1.5

4-41-27 5-10 3-5 0.6-2 6-20 4-13 0.3 - 1 12 - 42 1.2 - 3.8

*Rate and number of sprays suggested by product label. This is not a Purdue recommendation.
†Tomato uptake estimated at N: 182 lb/A; P2O5 48 lb/A, K2O 337 lb/A, for yield 30 tons/A. Lorenz and

Maynard 1980.Purdue University is an equal access/equal opportunity institution. 59

Foliar Fertilization When Root Uptake is Prevented –
Primary and Secondary Nutrients
Nutrient Lb/A Source

N 4 - 5 Urea, UAN, A N, A S, Ca N

K 1 - 4 K sulfate

Ca 1 -2 Ca nitrate, Ca chloride

Mg 1- 2 Mg sulfate

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Foliar Fertilization
Micronutrients
– Responsive crops
– Identified deficiency
– Soil application not practical or effective

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Foliar Fertilization - Micronutrients
Element Lb/A Source Highly Responsive Crops
Sodium
Beet, Broccoli, Carrot, Cauliflower, Celery,
B 0.1 - 0.3 borate, boric Parsnip, Rutabaga, Tomato, Turnip
acid
Bean, Cuke, Garlic, Greens, Lettuce,
Mn 1-2 Mn sulfate Onion, Pea, Potato, Pumpkin, Radish,
Spinach, Squash, Sweet corn
Zn 1/2 Zn sulfate Bean, Onion, Spinach, Sweet corn
Chelated elements may also be used; follow label instructions.
Reference: Nutrient Recommendations for Vegetable Crops in
Michigan, E2934. Warncke, Dahl and Zansdtra, 2004. 62
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Monitoring and Adjusting a Plan
In Season
– Soil nitrate test
– Plant tissue sampling
– On-farm plant or soil testing
After or Between Season
– Soil test
– End of season soil nitrate?

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Recordkeeping
Soil test results
Lime: type and tons/A
Fertilizers:
– Type, analysis, lbs./A
– Application method
Other soil amendments
– Type, nutrient content, lbs./A
Cover crops:
– Species, seeding rates, plant and termination
dates, termination method

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 Resources
Midwest Vegetable Production Guide for 2017 (ID-56) mwveguide.org/
Purdue Education Store edustore.purdue.edu Soil Sampling for P, K, and Lime AY-281-W
Nutrient Recommendations for Vegetable Crops in Michigan (E2934)
msue.anr.msu.edu/resources/nutrient_recommendations_for_vegetable_crops_in_michigan
_e2934
Managing Cover Crops Profitably: BUILDING SOIL FERTILITY AND TILTH WITH COVER CROPS
www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition
Using the Pre-Sidedress Soil Nitrate Test to Improve Nitrogen Management in Vegetable
Cropping Systems. https://soiltest.umass.edu/fact-sheets/using-pre-sidedress-soil-nitrate-
test-improve-nitrogen-management-vegetable-cropping
Indiana Nutrient Management/Soil Health https://inagnutrients-public.sharepoint.com

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Liz Maynard
219-548-3674
emaynard@purdue.edu
Clinical Engagement Assistant Professor and
Vegetable Extension Specialist
Dept. of Horticulture and Landscape Architecture
Purdue University
PO Box 1759
Valparaiso, IN 46384

66 Purdue University is an equal access/equal opportunity institution.