Fertilizers

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Fertilizers
For Soils 201 March 28th and 29th Phil Roberts
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Essential Plant Nutrients(Review from Week 1)

• C.B. Hopkins Café, Co.
• Closed Monday Morning and Night
• See You (Cu) Zoon, The Mg.
• See Table 1.1
• C,H,O N, P, K, Ca, Mg, S Fe, Zn, Mn, B, Cu
• Cl, Co, Mo, Ni

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The Big 3
N lab from week 9 P ATP the energy
currency, DNA, RNA K inorganic, non-toxic,
from minerals
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Fertilizer Grade

• 46-0-0 16-16-16 20-20-0
• 3 numbers on all commercial fertilizers
• Total Nitrogen NitrateAmmonium
• Available Phosphate Content P2O5
• Soluble Potash Content K2O
• P and K expressed in Oxide Forms

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How Much N,P, K in a Fertilizer?
Nitrogen is strait foreword The others
Arent. Atomic Weights P 31 K 39 O 16
2P in P2O5 so. (231) / (231 516)
44 2K in K20 so. (239) / (239 16) 83
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How Much N,P, K in a Fertilizer?
A bag of 20 20 20 fertilizer contains 20
Total Nitrogen 20 0.44 8.8 Elemental P 20
0.83 16.6 Elemental K
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How Much N,P, K in a Fertilizer?
Your Turn. What is the Elemental content of N,
P and K in a bag of 25 50 29 fertilizer ?
What is the weight of each element in a 40 lb.
Bag?
Part 1 25, (50.44), (29.83) 25-22-24
Part 2 40 lbs (25, 22, 24) 10 lbs N
8.8 lbs P 9.6 lbs K
Question What is the other 29 (11.6 lbs) ?
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Cost Calculations
Scotts Turf Builder 28-3-3 14.5lbs 11 Miracle-
Gro 15-30-15 5lbs 8 ACE Green Turf Winterizer
Weed And Feed 24-3-12 48lbs 35
Which fertilizer has the most N per Which
fertilizer has the most P per Which fertilizer
has the most K per
Scotts
Miracle-Gro
ACE
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Synthetic Fertilizers
Green Revolution Dramatic Increase in use since
1960s Most in inorganic forms salts
Problem with Salt Burn Problems with leaching
and eutrophication Fertigation
Plate 62
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Synthetic Fertilizers
Table 14.9 Page 494 Anhydrous Ammonia
83-0-0 liquid Urea-Ammonium-Nitrate
30-0-0 liquid Ammonium Nitrate
33-0-0 explosive Triple superphosphate
0-20-0 Diammonium phosphate 20-20-0 Potassium
Chloride 0-0-50 Potassium Nitrate 13 0 36
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Organic Fertilizers
Higher Water Contents Slower Availability
Involve microbial degradation Residual
Contributions over multiple growing
seasons Nitrogen Phosphorus Balance Higher N
demand Equivalent N and P content in most
organic fertilizers
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Organic Fertilizers

• Table 14.6 Page 486
• Blood Meal 13 1 - 1
• Bone Meal 4 15 0
• Dairy Cattle Manure 2.4 - 0.7 - 2.1
• Horse Manure 1.4 - 0.4 - 1.0
• Poultry Manure 4.4 2.1 2.6
• Sewage Sludge 4.5 2.0 0.3

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Application Methods
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Timing of Applications
Consider the following Nutrient
Mobility Environmentally Sensitive
Periods Field Limitations Physiological
Limitations
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The Future
GPS and Precision Agriculture (fig. 14.22 pg
507) GIS soil map, soil tests, fertilizer use
history, yield history, nutrient application
rates Equipment soil probes, variable rate
fertilizer aplicator/seeder yield monitoring
harvester.