Submitted to: Journal of Rio Grande Horticultural Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 1995
Publication Date: N/A
Interpretive Summary: Bell pepper fertilization in the subtropical Lower Rio Grande Valley of Texas has been studied and recommendations developed. The primary nutrient that needed to be applied for bell pepper production was nitrogen (N). However, response to N application only occurred when preplant soil N test levels were very low. When this occurred, fertilizer N application substantially improved yields, yet only a small percentage of the N applied was actually taken up by the crop. About 88% of the N applied to the site, which tested very low in soil N, remained in the soil after the crop was harvested. Since no yield increases resulted from any other fertilizers applied in the spring or fall, or any of the N fertilizer in the fall, all of those nutrients remain in the soil and become potential contaminants of ground and drainage waters and could negatively effect water quality.
Fertilization programs used commercially often vary substantially from what has been found to be effective. A fertilization program that is used commercially on a large area for pepper production in this area was evaluated at 2 different locations. Preplant soil tests showed NO3-N levels were very low at one location and very high at the other. Nitrogen application where preplant soil NO3-N was low resulted in substantial yield and quality improvements as well as in improvements in a number of other fruit components. No other nutrient application at either location, nor N application at the site where preplant soil NO3-N levels were high, caused any significant effects. Bell pepper storage characteristics were not affected by any fertilizer treatment, even where a yield response to N had been observed. Nitrogen application had the greatest effect on dry weight accumulation and N uptake late in the season and during fruiting when these processes were occurring most rapidly. Where N responses were observed, N application increased total dry weight in both plant and fruit by 150% and total N uptake by 186%, yet this increase amounted to a N fertilizer uptake efficiency of only 12%, leaving substantial potential for environmental pollution.