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Banding Fertilizers in Pecan Orchards

Banding Fertilizers in Pecan Orchards. Michael Smith Department of Horticulture & L.A. Oklahoma State University. Necrotic leaves near shuck split on Pawnee. July leaf P 0.114% and leaf K 0.62%.

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Banding Fertilizers in Pecan Orchards

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  1. Banding Fertilizers in Pecan Orchards Michael Smith Department of Horticulture & L.A. Oklahoma State University

  2. Necrotic leaves near shuck split on Pawnee July leaf P 0.114% and leaf K 0.62%

  3. Nut count, kernel %, kernel grade and return bloom improved with higher leaf P and K concentrations.

  4. Cultivar: PawneeAge:9 years Soil: Dennis silty clay loam Irrigation: subsurface drip Treatments: Control – N only; P – N + P; K – N + K; PK – N + P + K 2009 All trees: March 52 lb/acre N May 88 lb/acre N P: March 131 lb/acre P2O5 K: March 69 lb/acre K2O PK: March P rate + K rate 2010 All trees: March 104 lb/acre N P: March 262 lb/acre P2O5 K: March 138 lb/acre K2O PK: March P rate + K rate 2011 All trees: March 104 lb/acre N P: March 262 lb/a P2O5 K: March 138 lb/acre K2O PK: March P rate + K rate 2012 All trees: March 52 lb/acre N May 75 lb/acre N P: March 131 lb/acre P2O5 K: March 69 lb/acre K2O PK: March P rate + K rate

  5. July leaf P 2011 2012

  6. Drought started in 2010 and has continued to intensify. Trees on survival irrigation ration Surface water irrigation source Non-irrigated 2 miles south

  7. July leaf K 2011 2012

  8. Leaf symptoms Rating 1 Rating 3 Rating 5 Symptoms appear closely linked to P shortage, even in July.

  9. 2011 1-year-old branches with fruit 2010 branch type

  10. 2012 1-yr-old branches with fruit

  11. N & P on ‘Chickasaw’ near Baconton, GA Treatments: March 0 or 50 lb/a N Late July 0 or 100 lb/a N Late July 0 or 150 lb/a P2O5 N source: (NH4)2SO4 P source: Triple super phosphate Reps: 6 single trees

  12. Late July N & P application on next year current season shoots fruiting

  13. P & K in the rest of the field 18-46-0 (DAP), 0-46-0 (TSP), or 0-0-60 banded increases availability of those nutrients. Broadcast applications are generally ineffective. Applied with spinner off Note K band Healthy trees without deficiency symptoms as a result of banding 18-46-0 banded in March

  14. Tommy Bryant applying 18-46-0 in an orchard near Albany, GA

  15. Potassium banding on ‘Desirable’ in GeorgiaWood, Wells & Funderburke, 2010 • ≈25 years-old on Elliott rootstock • Faceville sandy loam soil • 30’ x 60’ spacing • Drip irrigated from 1 line on each side • 0-0-62 applied March in ≈ 6” wide band spanning several emitters. Applied on each side of the tree within the herbicide treated area. • Rates from 0 to 53 lb/tree K2O (0 to 1282 lb/acre K2O; 0 to 2068 lb/acre 0-0-62) • Measurements were at the end of stage 2 fruit drop, i.e. June drop.

  16. Potassium concentration in leaves, retain fruit and aborted fruit of ‘Desirable’ the 1st year following application Retained fruit Aborted fruit 0-0-62 applied in band (lb/acre)

  17. Fruit retention following K banding in March 2006

  18. Yield following March 2006 K banding

  19. Zinc banding of ‘Desirable’ in GeorgiaWood, 2007 • 15’ x 30’ (97 trees/acre) • 4-years-old at beginning of study • Faceville fine sandy loam • Drip irrigated • Buried line 4’ from trunk on each side of tree • Water delivery on surface 3’ apart • 1 gph operated 8 to 12 hours/day • Irrigation lines within herbicide strip • ZnSO4 or ZnO banded 4” x 13’ over drip line • 0 to 9.3 lb Zn/tree (0 to 25 lb ZnSO4; 0 to 12 lb ZnO)

  20. Leaf Zn following a single applicationWood considered 50 ppm as threshold 1st year 2nd year 4th year 3rd year

  21. Summary • Applying phosphorous, potassium and zinc in bands within the wetted area of drip irrigated trees is effective. • Phosphorus and potassium can be applied as a bulk blend. • Do not apply zinc in the same area where phosphorus was applied. • Similar results will probably be obtained when applied within the wetted area of micro-sprinkler or sprinkler irrigated orchards. • Banding about mid-way between the trunk and dripline should be beneficial on non-irrigated orchards, but the effectiveness will probably be reduced.

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