Holden Research and Consulting Cool Season Vegetables and Strawberry Response to Phosphates – Research and Observations over the last Ten Years David Holden
Holden Research and Consulting
Holden Research and Consulting Introduction • My Experience – Over 700 trials in the past ten years in nutrient and pest management for fruit, nut, and vegetable production. – Over 35 trials in the past ten years with phosphate based fertilizers on vegetables, strawberries, grapes, and trees.
Holden Research and Consulting Introduction • All phosphate trials were conducted in the coastal counties of Monterey, San Luis Obispo, Santa Barbara, and Ventura • Both ortho and poly – phosphates were involved. • Sometimes “organic acid” additives were involved, along with phosphorus “protecting” products.
Holden Research and Consulting University Recommendations University of California, ANR Publication 8098, Nutrient Management In Cool Season Vegetables
Holden Research and Consulting What are the Issues with Phosphorus Availability • pH • Temperature • Cation inhibition – Calcium – Zinc – Etc.
Holden Research and Consulting How Soil pH affects P 2 O 5
Holden Research and Consulting Cool Soils • Cool soils may induce phosphorus deficiency • With cool soils you have slower root growth and development • Less opportunity for roots to come in contact with the phosphorus they need at this time • Limiting phosphorus in cool seasons exacerbates the ability for cool season vegetables to grow.
Holden Research and Consulting Cation Inhibition • Calcium and zinc cations (and others) have an affinity for PO 4 , phosphate anion. • They form calcium and zinc phosphate precipitates which are now hard to resolubilize for root uptake. • But this also helps reduce leaching of PO 4 from the soil solution.
Holden Research and Consulting Plant Phosphorus Utilization • Forms nucleic acids (DNA and RNA) • Used in the making of the chemical energy molecules of ATP and ADP. • Through this transfer of chemical energy it is utilized in new growth and reproduction. • Note that dry leaf analysis of P 2 O 5 in young leaves is always higher than that found in older leaves.
Holden Research and Consulting Symptoms of Phosphorus Deficiency • Slow growth, stunted plants • Purplish coloration on foliage of some plants (older leaves first) • Dark green coloration • Delayed maturity • Poor fruit or seed development
Holden Research and Consulting Not So Obvious Symptoms of Phosphorus Deficiency • Poor root development • Reduced production – Sizing reduction – Fruit set reduction
Holden Research and Consulting
Holden Research and Consulting Phosphate vs. Phosphite or Phosphoric Acid vs. Phosphorous Acid • One is the source for a fertilizer, the other is a source for a fertilizer and a fungicide. • PO 4 vs. PO 3. PO 3 will (?) oxidize eventually to PO 4 • Know the difference. There is still quite a bit of confusion regarding these source products
Holden Research and Consulting Four Recent Trials with Phosphates in Peppers and Strawberries. • Phosphates generally placed in addition to the grower’s standard practices which may include pre-plant and in-season phosphate applications. • All crops grown on tape, which allows for precise in season placement of phosphate.
Holden Research and Consulting Early Spring 2010 Peppers • Pre-Plant poly phosphate applied as band under seedline on 4/27/10 • Pre-Plant Phosphorus (Olsen Method) – 41 ppm • Treat 1 – untreated • Treat 2 – 100 lb/ac P 2 O 5 as 10-34-0 • Treat 3 – 55 lb/ac P 2 O 5 as Proprietary • Treat 4 - 30 lb/ac P 2 O 5 as Proprietary • Planted 5/5/10
Holden Research and Consulting Chart 1: 2010 Spring - Summer Bell Pepper Phosphate Study - Camarillo, CA. - Total Yield per Plant 2.5 2.0 Pounds of Fruit 1.5 1.0 0.5 0.0 Lbs./Plant UTC 1.6 b Reduced Propietery 2 1.6 b Reduced Propietery 1 1.8 ab Grower Standard 2.3 a
Holden Research and Consulting Post Treat Soil P 2 O 5 Levels • Treat 1 – 30 ppm • Treat 2 – 31 ppm • Treat 3 – 34 ppm • Treat 4 – 27 ppm
Holden Research and Consulting Late Spring 2010 Peppers • Pre-Plant poly phosphate applied as band under seedline on 6/17/10 • Pre-Plant Phosphorus (Olsen Method) – 44 ppm • Treat 1 – 125 lb/ac P 2 O 5 as 10-34-0 • Treat 2 – 100 lb/ac P 2 O 5 as 10-34-0 • Planted 6/20/10
Holden Research and Consulting Chart 2: 2010 Late Spring - Summer Bell Pepper Phosphate Study - Camarillo, CA. - Total Yield per Plant 2.5 2.0 Pounds of Fruit 1.5 1.0 0.5 0.0 Lbs./Plant 100 lb P2O5 2.1 125 lb P2O5 2.2
Holden Research and Consulting Post Treat Soil and Leaf P 2 O 5 Levels • Treat 1 – 40 ppm • Treat 2 – 49 ppm • Leaf Treat 1 - .32% • Leaf Treat 2 - .35%
Holden Research and Consulting 2008-09 Strawberries • Planted 10/2/08 • All Received Pre-Plant and in-Season Phosphate • 500 lb/ac 18-8-13 slow release • Approximately 20 gal/ac Phosphoric acid in season (150 lb P 2 O 5 ) in tape • Experimental Treatment received another 80 lb/ac of P 2 O 5 in the tape and 40 lb/ac of P 2 O 5 foliar as Proprietary Product
Holden Research and Consulting Plant Sizing at Nine Weeks after Planting Grower Standard Additional Phosphate
Holden Research and Consulting Chart 6: Proprietery 2008-09 Strawberry Nutrient Study - Camarillo, CA. - Cumulative Marketable Production by Pick Day 5000.0 4500.0 4000.0 Trays per Acre (10 lb. equivalent) 3500.0 3000.0 2500.0 2000.0 1500.0 1000.0 500.0 0.0 12/8/08 1/3/09 1/7/09 1/12/09 1/16/09 1/19/09 1/21/09 1/24/09 1/28/09 2/3/09 2/6/09 2/10/09 2/16/09 2/20/09 2/24/09 2/27/09 3/2/09 3/5/09 3/9/09 3/12/09 3/16/09 3/21/09 3/25/09 3/28/09 4/1/09 4/6/09 4/10/09 12/11/08 12/16/08 12/20/08 12/22/08 12/24/08 12/27/08 12/30/08 Pick Day Grower Standard Proprietery
Holden Research and Consulting Chart 6: Proprietery 2008-09 Strawberry Nutrient Study - Camarillo, CA. - Early Cumulative Marketable Production by Pick Day 1200.0 155 flats ahead 1000.0 Trays per Acre (10 lb. equivalent) 800.0 600.0 400.0 200.0 0.0 12/8/08 12/11/08 12/16/08 12/20/08 12/22/08 12/24/08 12/27/08 12/30/08 1/3/09 1/7/09 1/12/09 1/16/09 1/19/09 1/21/09 1/24/09 1/28/09 2/3/09 2/6/09 2/10/09 2/16/09 2/20/09 2/24/09 2/27/09 Pick Day Grower Standard Proprietery
Holden Research and Consulting Chart 6: Proprietery 2008-09 Strawberry Nutrient Study - Camarillo, CA. - Late Cumulative Marketable Production by Pick Day 5000.0 57 flats behind 4500.0 4000.0 Trays per Acre (10 lb. equivalent) 3500.0 3000.0 2500.0 2000.0 1500.0 1000.0 500.0 0.0 3/2/09 3/5/09 3/9/09 3/12/09 3/16/09 3/21/09 3/25/09 3/28/09 4/1/09 4/6/09 4/10/09 Pick Day Grower Standard Proprietery
Holden Research and Consulting Conclusions • Additional Early Season applications of P2O5 did help increase early season production • As soils warmed and crop finished out the end season differential was not as great • Early season production does return the grower a better price per flat.
Holden Research and Consulting 2009-10 Strawberries • Planted 10/3/09 • All Received Pre-Plant and in-Season Phosphate • 500 lb/ac 18-8-13 slow release • Approximately 20 gal/ac Phosphoric acid in season (150 lb P 2 O 5 ) in tape • Experimental Treatment received another 45 lb/ac of P 2 O 5 in the tape as 3-18-18 (ortho phosphate) over five applications • Also Proprietary product run alone and in combination with 3-18-18
Holden Research and Consulting Plant Sizing at Nine Weeks Grower Standard Product A 3-18-18/Product A 3-18-18
Holden Research and Consulting Chart 8: Proprietery Trial on Strawberries - Ventura County, Fall/Winter 2009-2010 - Cumulative Marketable Production by Pick Day 6000.0 5000.0 Trays per Acre (10 lb. equivalent) 4000.0 3000.0 2000.0 1000.0 0.0 1/4/10 1/11/2010 1/15/2010 1/18/2010 1/22/2010 1/25/2010 1/29/2010 2/12/2010 2/16/2010 2/22/2010 2/25/2010 3/11/2010 3/15/2010 3/18/2010 3/22/2010 3/26/2010 3/29/2010 12/14/2009 12/17/2009 12/22/2009 12/27/09 12/30/09 1/8/2010 2/1/2010 2/4/2010 2/8/2010 3/1/2010 3/4/2010 3/8/2010 4/2/2010 4/5/2010 4/9/2010 1 2 3 4 5 6 7 8 9 10 11 12 12 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Pick Day Product A/3-18-18 Product A Alone Grower Standard 3-18-18 Alone
Holden Research and Consulting Chart 8a: Proprietery Trial on Strawberries - Ventura County, Fall/Winter 2009-2010 - Cumulative Marketable Production by Pick Day 800.0 700.0 600.0 Trays per Acre (10 lb. equivalent) 500.0 400.0 300.0 200.0 100.0 0.0 12/14/2009 12/17/2009 12/22/2009 12/27/09 12/30/09 1/4/10 1/8/2010 1/11/2010 1/15/2010 1/18/2010 1/22/2010 1/25/2010 1/29/2010 1 2 3 4 5 6 7 8 9 10 11 12 12 Pick Day Product A/3-18-18 Product A Alone Grower Standard 3-18-18 Alone
Recommend
More recommend
