Reducing Orchard Fertilizer Costs

Lenny Wells

UGA Horticulture

Fertilizer Costs

• Ammonium Nitrate (33% N) 2007/08 = $457/ton

» ($103.86/Acre based on 150 lbs N/A)

• Phosphorous (44% P205)» $12.80/Acre (40 lbs/A)

• Potash (51%K) 2007/08 = 475/ton (51%K)

» ($28.50/acre based on 60 lbs K/acre)

• Zinc $17.50/Acre (50 lbs/Acre)• Total: $162.66/Acre

Are we using too much N?

• Yield and leaf N of Mature ‘Stuart’ trees in good condition did not respond to N at rates of 0-120 lbs/A until 6 years later (Worley 1974).

• Pecan Orchards cycle nutrients

Why is Organic Matter Important?

• Higher inputs required with lower organic matter• Increased Water-Holding Capacity• Nitrate provided to plants via mineralization as soil organisms

decompose organic matter• Neg. charged humus holds K, Ca, Mg, preventing loss• Provides natural chelates that keep Zn and Cu in forms plants

can use• Reduced compaction, better water-holding capacity, reduced

erosion• Slows down (Buffers) changes in pH• For every 1% increase in organic matter , 10 lbs N

released• Crop yield increased 12% for every 1% increase in

organic matter

N Credit for Legumes

• General N Recommendation for Pecans 10 Lbs N/ 100 lbs expected crop

• Crimson Clover Year 1 = Replaces 30 lbs N/Acre

On Year = 150 lbs N-30 lbs N = 120 lbs N/AcreOff YEAR= 75 lbs – 30 lbs = 45 lbs N/Acre

After 3 Years = Replaces 75-150 lbs N/AcreOn Year = 150 lbs N – 100 lbs N = 50 lbs N/AcreOff Year = No additional N required

Effect of Clover on Organic Matter and N

Sample Site Nitrate-N Organic Matter

4” Sod 3.78 1.34

8” Sod 4.18 1.66

4” Sod+Clover 13.95 2.32

8” Sod + Clover

10.75 2.90

Orangeburg Loamy Sand

Poultry Litter Costs

• Total Synthetic Cost N,P,K,Zn = 162.66• 1 ton litter = $35-$50

1 appl.: $50/Acre for 39 lbs N, 48 lbs P, +K, +Zn 2 appl.: $100/Acre for 78 lbs N, 96 lbs P, +K, +Zn

• Not much difference if N is only benefit

(@ $50/ton)

Nitrogen Costs(Assuming 150 lbs N for ON year)

Broadcast Ammonium Nitrate

Clover + Ammon. Nitrate

Clover + Litter

On Year $103.86/Acre $34.27/Acre $50-$75/Acre

Off Year $51.83/Acre $0/Acre $0/Acre

If only N needed If N,P,K,Zn needed

Band Applications

• Apply fertilizer over the drip emitter line• More efficient/reduced fertilizer cost

• Determine area of application!

Which makes more sense?(100 acre orchard on 60 X60)

Broadcast Ammonium Nitrate

Clover + Ammon. Nitrate

Clover + Litter

Clover+ Band Appl.

On Year(150 lbs N/Acre)

$103.86/Acre $34.27/Acre $50-$75/Acre

$9.20/Acre

Off Year(75 lbs N/Acre)

$51.83/Acre $0/Acre $0/Acre $0/Acre

Boron Recommendations

• Can increase fruit retention and kernel percentage• 3 pre-pollination applications of B beginning

before catkins are mature• No benefit to making more than 3 applications

Nickel

• Improves Mouse-ear Symptoms• Effects of Nickel on N metabolism in pecan:

Can influence the efficiency of early spring N conversion and transport within the pecan tree (Bai et al. 2007).

• 2 applications: Early to mid April and again 2-4 weeks later

Weed Control and Clover

15 Days After Treatment

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Wild Geranium

Weed Control and Clover21 Days After Treatment

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Wild Geranium

• Sandea (Halosulfuron-methyl) Excellent on wild turnips (pre and post-emergence) Good activity on wild geranium Good control of rye-grass Potential Problems:

Cost = $15/acre @ 0.5 oz/acre Delayed clover development; possible effect on seed viability

• Basagran Cost = $16/acre @ 2 pints/acre Problems: For use only on Non-Bearing Pecans

Wild turnip must be treated up to a weed height of 3”

Best results on geranium will be achieved when weeds are small

Heavier the Infestation, earlier the treatment

Yet To Be Determined:

• 2,4-DB-amine used for the control of many annual and perennial

broad-leaved weeds in alfalfa, peanuts, soybeans Labeled for clover

• Timing and rates

Uses 5% Glyphosate solution (1.25 gal./25 gal water) + 4% 2,4-D amine

Controls difficult weeds like:hophornbeam copperleaf, grasses, and arrowleaf sida

Cost per acre varies with weed density