Greenhouse and field applications of various organic nitrogen fertilizer sources
Current nitrogen fertilizer programs for organic flue-cured tobacco production have proven successful but are not absent of agronomic concern. In the current evaluation, different organic nitrogen sources were evaluated for their usability in seedling and field production. Sources evaluated for seedling production were Seabird Guano, Feather Meal, Blood Meal, Liquid Chicken Litter + Sodium Nitrate, Sodium Nitrate, Corn Gluten, Soy Protein, Dry Chicken Litter, and Fish Emulsion. A conventional control was included for comparison (SQM Ultrasol Premium 16-5-16). Analysis of float water samples over a 60-day timespan revealed that treatments containing Liquid Chicken Litter + Sodium Nitrate, Sodium Nitrate, and SQM Ultrasol Premium 16-5-16 contained the highest nitrate-N and lowest ammonium-N concentrations. The same treatments contained the lowest bicarbonate concentration between 10 and 40 days after seeding (≤ 4 meq HCO3-/L). At the conclusion of the study SQM Ultrasol Premium 16-5-16, Seabird Guano, Liquid Chicken Litter + Sodium Nitrate, and Fish Emulsion produced the highest number of usable seedlings. Treatments comprised of Blood Meal, Sodium Nitrate, Corn Gluten, and Soy Protein produced the fewest usable seedlings due to severe phosphorus deficiency. In the field evaluation, cured leaf yield was as follows: Sodium Nitrate > Soy Protein ≥ Blood Meal ≥ Seabird Guano > Corn Gluten ≥ Feather Meal ≥ Dry Chicken Litter > Non-treated Control. Cured leaf value followed a similar trend. Liquid Chicken Litter + Sodium Nitrate and Fish Emulsion were excluded from the field study. Preliminary results suggest that Liquid Chicken Litter + Sodium Nitrate and Fish Emulsion might be suitable alternatives to Seabird Guano in the float system and that Soy Protein may serve as another option for field production.