Organic Transplant Production: An Evaluation of Nitrogen Fertility Programs

Transcription

1 Organic Transplant Production: An Evaluation of Nitrogen Fertility Programs M.C. Vann, L.R. Fisher, & R.W. Seagroves Department of Crop and Soil Sciences North Carolina State University M.S. McGinnis North Carolina Department of Agriculture & Consumer Services-Agronomic Division

2 Presentation Outline Organic Seedling Production Production Concerns Methods & Materials Results & Discussion Conclusions Questions

3 Organic Seedling Production Production occurs in a float system Nutrients are added directly to the water OMRI listed soilless media sources Common Nutrient Sources: Allganic Sodium Nitrate ( or ) Peruvian Seabird Guano ( ) Bat Guano Allganic Potassium Sulfate (0-0-52) Acetic acid for bicarbonate adjustments Micronutrient sources vary depending upon need

4 Organic Seedling Production Concerns Variable N composition of nutrient sources Sodium Nitrate: 0% Urea, 0% NH 4+, 100% NO 3 - Seabird Guano: 69% Urea, 30% NH 4+, 0.65% NO : 0% Urea, 37.5% NH 4+, 62.5% NO 3 - Variable rate of N mineralization Aerobic vs. Anaerobic conditions (field vs. float bed) Difficult to dissolve guano in solution High bicarbonate concentration 2.0 meq HCO 3- /L (>200 mg/l) can stunt seedlings (2,4) High P concentration leggy / spindly seedling characteristics (3) High Na concentration <70 mg Na/L is recommended (4) High Urea and NH 4+ concentration (5) Excessive NO 2- is toxic to seedlings Low microbial populations for oxidation in media

5 Objectives 1. Identify organic fertilizer programs best suited for seedling production 2. Identify concerns associated with those programs 3. Further develop Extension recommendations

6 Methods & Materials Treatment List 1. Guano 2. Guano + Gypsum 3. Sodium Nitrate 4. Sodium Nitrate + Gypsum 5. Guano + Sodium Nitrate 6. Guano + Sodium Nitrate + Gypsum (conventional control) Experimental Design Central Crops Research Station June-July 2016 November 2016-January 2017 RCBD, 3 replications per evaluation 6 trays per bed 100 designated cells/tray for data collection 12.7 cm float water depth Fertilizer added 9 and 21 DAS Variety: K326 (Rickard Seed Co.) Media: Carolina Choice All Natural Mix Data analyzed using PROC Mixed in SAS ver. 9.4 Figures created using Sigma Plot ver. 12

7 Table 1. Organic fertilizer programs evaluated and the respective targeted nutritional content. Fertilizer Program a,b,c Total N P 2 O 5 K 2 O Ca mg L -1 Guano (SG) (0-0-52) -- Guano + Gypsum (SG) (0-0-52) 50 Sodium Nitrate (0-0-52) -- Sodium Nitrate + Gypsum (0-0-52) 50 Guano + Sodium Nitrate 44 (SG) + 81 (SN) 40 7 (SG) (0-0-52) -- Guano + Sodium Nitrate + Gypsum 44 (SG) + 81 (SN) 40 7 (SG) (0-0-52) a Guano (SG), Sunleaves Peruvian Seabird Guano; Sodium Nitrate (SN), SQM Allganic ; , SQM Ultrasol Premium; , SQM Allganic Potassium Sulfate b Fertilizer program applied twice per season, 9 and 21 days after seeding c Nutrient content calculated based upon manufacturers reported analysis

8 Data Collection Dissolved Oxygen: YSI DO Meter 5 day intervals prior to solution collection and water addition Solution Samples: Source Water 5 day intervals 474 ml solution volume After beds filled to 12.7 cm depth Samples analyzed by NCDA&CS Media Samples: 20 DAS and at conclusion of study 10 cells/tray/treatment N=60/treatment/replication Samples analyzed by NCDA&CS Seedling Measurements: Total plants, usable plants, stem height, & stem diameter Conclusion of study 10 cells/tray/treatment N=60/treatment/replication

9 2018_TWC17_Vann.pdf

10 Table 2. Nutrient concentration, ph, and bicarbonate concentration of source water and soilless media prior to seeding a. Measurements are expressed in mg L -1 unless otherwise noted. Nutrient Environment One Environment Two Solution Media Solution Media Total N min NH 4+ -N NO 3- -N Urea-N P K Ca ph HCO 3- (meq L -1 ) a Soilless media and source water solution samples analyzed by the North Carolina Department of Agriculture and Consumer Services-Agronomic Division, Raleigh, NC

11 DO Concentration (mg DO L -1 ) 2018_TWC17_Vann.pdf Environment One Guano Guano + Gypsum Sodium Nitrate Sodium Nitrate + Gypsum Guano + Sodium Nitrate Guano + Sodium Nitrate + Gypsum Environment Two Days After Seeding Figure 1. Dissolved oxygen (DO) concentration in float water solution as influenced by seedling fertility program. Data are presented for each growing environment.

12 Ammonium-N Concentration (mg NH 4 + L -1 ) Environment One Environment Two Guano Guano + Gypsum Sodium Nitrate Sodium Nitrate + Gypsum Guano + Sodium Nitrate Guano + Sodium Nitrate + Gypsum Days After Seeding Figure 2. Ammonium-nitrogen concentration in float water solution as influenced by seedling fertility program. Data are presented for each growing environment.

13 Nitrate-N Concentration (NO 3 - L -1 ) Guano Guano + Gypsum Sodium Nitrate Sodium Nitrate + Gypsum Guano + Sodium Nitrate Guano + Sodium Nitrate + Gypsum Environment One Environment Two Days After Seeding Figure 3. Nitrate-nitrogen concentration in float water solution as influenced by seedling fertility program. Data are presented for each growing environment.

14 8.0 Environment One 8.0 Environment Two ph Guano Guano + Gypsum Sodium Nitrate Sodium Nitrate + Gypsum Guano + Sodium Nitrate Guano + Sodium Nitrate + Gypsum Days After Seeding Figure 4. Float water solution ph as influenced by seedling fertility program. Data are presented for each growing environment.

15 Bicarbonate Concentration (meq HCO 3 - L -1 ) Guano Guano + Gypsum Sodium Nitrate Sodium Nitrate + Gypsum Guano + Sodium Nitrate Guano + Sodium Nitrate + Gypsum Environment One Environment Two Days After Seeding Figure 5. Bicarbonate concentration in float water solution as influenced by seedling fertility program. Data are presented for each growing environment. Dashed line represents 2.0 meq threshold.

16 250 NH 4 + -N NH 4 + or NO3 - Concentration (mg L -1 ) NO 3 - -N ph ph NH 4 + or NO3 - Concentration (mg L -1 ) ph Days After Seeding Figure 6. Ammonium, nitrate, and float water ph as influenced by guano application. Data are presented for each growing environment.

17 Additional Solution Observations Urea-N concentration: Guano > Guano + Sodium Nitrate > Sodium Nitrate Maximum of mg/l, decreased over time P concentration: Guano > > Guano + Sodium Nitrate > Sodium Nitrate Maximum of mg/l in Guano only treatment <1.0 mg/l observed in Sodium Nitrate only treatment Na concentration: Sodium Nitrate > Guano + Sodium Nitrate > Guano > >350 mg/l observed in Sodium Nitrate only treatment High Na did not impact seedling growth, Coggins (4) did not observe injury at 580 mg/l

18 Soilless Media Nutrition Similar trends to nutrient concentration in float water solution Guano based treatments had highest NH 4+ concentration High NO 3- concentration where sodium nitrate was exclusive N source NO 3- concentration increased from the 20 DAS sampling to the conclusion of the study NH 4 + concentration decreased Low P (<1.0 mg/kg) concentration when Sodium Nitrate was the only N source Soluble salts (SS) concentration highest when Sodium Nitrate was included in fertility program. SS injury was not observed in either environment Delayed and split fertilizer application was likely beneficial

19 Table 3. Total transplants, usable transplants, transplant height, and transplant diameter reported by corresponding treatment as affected by fertility programs a,b. Treatment List c Total Plants Usable Plants Stem Diameter Stem Height % mm plant -1 cm plant -1 Guano 90 a 78 c 2.76 b 5.62 b Guano + Gypsum 91 a 79 bc 2.84 b 6.08 ab SodiumNitrate Sodium Nitrate + Gypsum Guano + Sodium Nitrate 91 a 85 ab 3.48 a 6.27 ab Guano + Sodium Nitrate + Gypsum 93 a 86 a 3.43 a 6.47 ab a 79 bc 3.30 a 6.62 a a Treatment means followed by the same letter within the same column are not significant at the α=0.05 level. Data are pooled across two environments. b Treatments comprised of Sodium Nitrate only removed from analysis c Guano, Sunleaves Peruvian Seabird Guano; Sodium Nitrate, SQM Allganic ; , SQM Ultrasol Premium

20 SG SG Gypsum SG Gypsum SG Gypsum SG, Seabird Guano , Sodium Nitrate

21 2018_TWC17_Vann.pdf Guano Guano Guano Gypsum

22 Conclusions 5 of 7 treatments produced acceptable transplants Treatments absent of P did not produce usable transplants (Sodium Nitrate only) Supplemental P is required, not enough in source water or media Organic blend treatment was best treatment. Guano + Sodium Nitrate (+ Gypsum) Produced highest number of usable transplants Balanced ammonium:nitrate ratio (1:2 or 1:3) HCO 3- concentration is more favorable for seedling growth Identified Guano as a source of HCO 3 - Delayed/split fertilizer application may reduce HCO 3- stunting Low media ph buffers against significant ph increase from HCO 3 -

23 Grower Recommendations Fertilizer Programs Program One: Seabird Guano (13.9 oz./100 gal) 104 g /100 L H 2 O ( oz./100 gal) g/100 L H 2 O Program Two: Seabird Guano (4.9 oz/100 gal) 37 g /100 L H 2 O Sodium Nitrate (6.8 oz/100 gal) 51 g /100 L H 2 O (3.0 oz/100 gal) g/100 L H 2 O Considerations Reduce guano particle size Soak guano in hot water for 24 hours Fertilize in split applications 9 and 21 DAS Target 125 mg N/L Target 40 mg P/L Target 125 mg K/L Apply Ca, Mg, S, and B as needed

24 References 1. USDA-NASS Certified Organic Survey-2015 Summary. Accessed September 25, NCDA&CS Solution Analysis for Tobacco Transplant Float Beds. Accessed September 25, Fisher, LR and MC Vann Producing Healthy Transplants in a Float System. In: LR Fisher, editor, 2017 North Carolina State University Flue-Cured Tobacco Production Guide (AG-187 (Revised)). Raleigh, NC: North Carolina Cooperative Extension Service. p Coggins, TE Effect of Sodium and Bicarbonate on Tobacco Seedling Production in the Greenhouse Float System [thesis]. Raleigh, NC: North Carolina State University. p Pearce, RC, Y Zhan, and MS Coyne Nitrogen Transformations in the Tobacco Float System. Tobacco Science 42(4):82-88.

25 Acknowledgements Technical Assistance Rick Seagroves Scott Whitley Hunter Mason Michelle McGinnis NCDA&CS Material Donation SQM Carolina Soil Company Rickard Seed Company

26 Questions?? Matthew C. Vann: Website: tobacco.ces.ncsu.edu North Carolina