Slow Release Fertilizer has no Effect on Soil and Plant Nitrogen and Fruit Yield in Bell Pepper (Capsicum annum L.)

Aims: To evaluate the effects of combining slow release fertilizer (SRF) with conventional N fertilizer on the levels of soil nitrogen (N), leaf N, and yield of bell pepper plants.

Study Design: The design was a randomized complete block with a factorial arrangement. There were four treatments [2 N fertilizers x 2 N rates (200 kg/ha N and 280 kg/ha N)] and four replications. The N fertilizers treatments were calcium nitrate + SRF and calcium nitrate (CN) alone as the control. The rate treatments were 200 and 280 kg/ha N.

Place and Duration of Study: Horticulture Farm, Department of Horticulture, Tifton Campus, University of Georgia, spring of 2008.

Methodology: Bell pepper ‘Heritage’ (Harris Moran, Modesto, Calif., U.S.) transplants were planted on 10 Apr. 2008 in two rows of plants per bed, with a distance between plants of 0.30 m. Soil and leaf nitrogen and other nutrients were monitored during the season.

Results: There were no consistent differences in the concentrations of NH4+-N and NO3--N at both 0-30 cm and 30-60 cm soil depth between CN + SRF and CN alone. Leaf N concentrations 40 DAT and 68 DAT were higher in plants fertilized with CN + SRF compared to the control, while there were no differences in leaf N concentration 98 DAT. Leaf N concentration was increased at the highest N fertilization rate. Marketable and total fruit yields and individual fruit weight were unaffected by fertilizer treatment and N rate.

Conclusion: Utilization of a slow-release fertilizer (combined with calcium nitrate) had no benefit in reducing soil N losses or in increasing leaf N status and bell pepper fruit yields.