Nitrogen Concentrations Affect Pepper Yield and Leachate Nitrate-nitrogen from Rockwool Culture

Abstract

Experiments were conducted to determine the effect of varying solution N concentrations on fruit yield and NO 3 -N concentration in leachate from rockwool-grown `Midal' peppers ( Capsicum annuum L.) in Florida. Treatment 1 plants received a series of nutrient solutions containing N at 60, 90, and 120 mg·liter –1 (60–90–120 mg·liter –1 ) during their growth cycle. Plants in treatments 2 and 3 were grown with N at 120 or 175 mg·liter –1 , respectively, throughout their entire growth cycle. Two trials were conducted; trial 1 from 17 Nov. 1991 to 1 July 1992, and trial 2 from 31 July 1992 to 23 Feb. 1993. In both trials, total marketable fruit weight was significantly ( P ≤ 0.05) higher (16% to 67%) for plants grown with N at 175 than with 60–90–120 mg·liter –1 . In trial 2, plants receiving N at 175 mg·liter –1 produced significantly more fruit (8%) and 14% higher total fruit weight than plants receiving N at 120 mg·liter –1 . The trend toward higher yield with N at 175 rather than 120 mg·liter –1 also occurred during trial 1, but differences were not significant. Nitrogen concentration did not significantly affect the percentage of total fruit having blossom-end rot in either trial (41% in trial 1; 13% in trial 2). Nitrogen at 175 mg·liter –1 resulted in 10% to 40% increases in total nutrient solution use and 2.5- to 3.5-fold increases in leachate NO 3 -N concentration compared to N at 120 mg·liter –1 .