N-P-K and Calcium in Drip Irrigated Onions and Processing Tomatoes

Transcription

1 N-P-K and Calcium in Drip Irrigated Onions and Processing Tomatoes Don May, Farm Advisor Emeritus, UC WSREC Michelle Le Strange, UCCE Farm Advisor, Tulare/Kings Counties Blaine Hanson, Irrigation Specialist, UC Davis

2 Growers are Switching to Drip Irrigation Water Management is Different frequency and amounts? Fertilizer Management is Different sources, amounts, placement? GOALS are the same: GOOD CROP Resource Efficiency Environmentally Friendly HOW to Grow with Drip?

3 Fresh Market Onion Drip Irrigation & Fertilizer Field Studies UC WSREC, Fresno County and 2007 Variety CHIEF Plant week of January 22 Harvest week of August 25 Irrigation Soil Solid set sprinklers for emergence and herbicide Subsurface DRIP start May 1 (onions 4-6 tall) stop July 25 Panoche Clay Loam Nitrogen in Soil Total N level before planting = 0.06%

4 Table 1: Effect of N Rate and Source on Onion Yield * 7 weekly applications through drip after bulbing started (May 11 - June 22)

5 Table 2: Comparison of Slow Release Fertilizers to UN 32 under Drip Irrigation Onion Yield - Tons/Acre * UN 32 and Agrotain - 7 weekly applications (May 11 - June 22) ** GP products 3 weekly applications (May 11 - May 25) GP 39 = 80% CAN % NFusion GP 40 = 60% CAN % NFusion

6 Table 3: Effect of Phosphate* on Onion Yield * All phosphate applied preplant Soil P (Olsen) 8 ppm each year (field location was side by side) Onions planted late January, harvested late August

7 Table 4: Effect of Applied Water on Yield and Quality Drip Irrigated Fresh Market Onions Pre-irrigation + sprinkler irrigation was 12 water applied prior to drip. Drip irrigation was started when the plants were 3-4 inches tall. Applied water of the 100% treatment was determined from standard crop coefficients of onion and reference crop ET.

8 Table 5: Onion Irrigation for Comparing ET and High and Low Pressure Drip 2007 Inches Yield Treatment % ETC App Drip Tons/Acre 7 High Pressure A 2 Low Pressure A 6 High Pressure AB 5 High Pressure AB 3 Low Pressure B 4 Low Pressure B 1 Low Pressure B P Value 0.01 CV (%) 7.3 Note: Low Pressure = 3 psi High Pressure = 10 psi

9 Processing Tomato Drip Irrigation & Fertilizer Studies UC WSREC 2006 & 2007 Variety H 9780 & H 9665 Plant Method Plant Harvest Irrigation Soil Direct Seeded Early March Mid August Solid set sprinklers for emergence and to set herbicide. Subsurface DRIP started after layby. 6-inches (sprinkler) + 18-inches drip = ~24 total Panoche Clay Loam Nitrogen in Soil Total N level before planting = 0.06%

10 Table 6: Comparison of Slow Release Fertilizers to UN 32 Under Drip Irrigation Tomato Yield * UN 32 - Seven weekly applications (May 24 - June 28) ** GP products Three weekly applications (May 24 - June 7) GP 33 = 80% UN % NFusion GP 07 = 60% UN % NFusion Preseason soil sample top 18-inches: NO3--N = 20 ppm NH4+-N = 8 ppm ~160 lbs of potential available Nitrogen

11 Table 7: Phosphorus Rate & Placement Method Processing Tomato Yield - Tons/Acre Preseason soil P level = 2 ppm (Olsen) in top 18. * All plots received 25 lbs P 2 O 5 preplant. Drip applied P = PhosAcid and Sidedress P = ** 2 foliar applications (1 gal) of Essential ( ).

12 Table 8: Effect of Potassium Rate applied in DRIP Processing Tomato* 2006 & 2007: Potassium applied as KCl in 2 applications through drip system about 45 and 30 days before harvest (August) Variety = H 9780 (2006) and H 9665 (2007)

13 Table 9: Effect of applied water on Yield & Solids of commercial Processing Tomato varieties grown under Drip Irrigation inches of water applied via sprinkler prior to start of drip irrigation. ETc differences initiated 60 days before harvest.

14 Table 2 - Processing Tomato Yield and % Solids of Irrigation Drip Placement Drip " Water Yield Difference in T/A Row Placement Pressure Applied T/A % Solids HP vs LP Mean Drip Placement Buried HP A 4.7 LP A Every furrow HP A 4.6 LP A Every other HP B 4.7 furrow LP B N.S. HP = High Pressure 9-10 psi LP = Low Pressure 3-4 psi

15 Observations about ONIONS N Rates: lbs N/acre (growers fine tune) under DRIP N Source: Cheapest (CN9 may improve firmness) P Rates: No Yield increase Same Bulb Firmness (expect yield response with low P in soils - 8 ppm) Additives: May benefit quality May increase yield (not consistent) Water: ETc % (best yields, no drop in quality)

16 P Rates: 200 lbs P 2 O 5 improved yield >15 Observations PROCESS TOMATO Tons/A under DRIP (definite yield response with low P in soils - 2 ppm) 3. P Method: Drip + Sidedress = best Drip more efficient than sidedress (if can t do both, then apply through drip) KCl: No yield or solids gain (with late season applications of 120 lbs/a) Water: More potential with drip to get high yields and acceptable solids, than with furrow

17 SUMMARY in these drip irrigation studies Onions and Processing Tomatoes need about the same amount of N and have comparable yields of T/A. 1. Slow-release N yielded similar to conventional N, but formulations and timings are still being evaluated. Tomatoes may have more potential than Onions. 1. Onions require about 33% MORE water than tomatoes for maximum yields.

18 Thank You Any questions? Acknowledgements: Netafim USA - Gills Onions - YARA North American, Inc (CAN 17, CN9) Companies that participated and donated product and financial support THANK YOU!