Yield and Nutrient Influences of Organic Fertilizer Blends in a Plasticulture Tomato System

We conducted a replicated trial of two fertilizer products derived from chicken (Gallus gallus) production to test their efficacy on the growth and yield of large-fruited tomatoes (Lycopersicon lycopericum Karst). We blended together a litter-based 3-0.87-2.49 N-P-K fertilizer and a feather-based 7-0.87-1.66 N-P-K fertilizer to create a complete pre-plant fertilizer (5.1:1:2.8 N:P:K) that we used to grow slicing tomatoes in raised beds with drip irrigation and plastic mulch. Despite being bulkier than salt-based fertilizers, application of the products was easy prior to final bed shaping. We applied the blended materials at four effective total N rates: 75, 150, 225 and 300 lbs./acre, with four replications. None of the treatments resulted in significant differences (p < 0.05) in fruit yield or quality. However, all of the yield and quality categories measured had p-values below 0.17, and four of the eight categories of yield and fruit count had p-values less than 0.10, indicating the need to repeat the study. Increasing application rate increased leaf magnesium concentration. Application rate did not significantly alter leaf concentration of nitrogen, phosphorus, potassium or calcium. Increasing the application rate resulted in increased leaf tissue manganese and boron concentrations. The product blends also had a highly significant influence on manganese concentration in the leaf tissue, more so than for any other nutrient tested. Chicken litter-based fertilizers often increase tissue copper concentrations and there was an indication that the blends we tested also increased copper levels in the leaves, although the effect was not consistent as rates increased.