Nitrogen Fertilization Rate and Plant Population Affect Yield and Quality of Drip-irrigated Bell Pepper

The effect of nitrogen applied at 180, 270, or 360 kg·ha^-1, with plant populations of 30750, 46125, or 61500 plants·ha^-1 of 'Galaxy' bell pepper (Capsicum annuum var annuum Grossum group) was examined in a complete factorial experiment. Plants were set in the field with 2, 3, or 4 rows/bed, with a single drip tape in the center of the 2-row beds and drip tape centered between outer 2-rows of the 3- and 4-row beds.  Drip tapes with different delivery rates were used to maintain an equal water application rate/plant in all plots. Plant leaf area and dry matter accumulation decreased linearly as plant population increased from 30750 to 61500 plants·ha^-1.  Total N concentration was not influenced by plant population, but plant N uptake decreased linearly as population increased.  Plant N concentration increased linearly as N rate increased from 180 to 360 kg·ha^-1; no other parameter was influenced by N rate. At the second harvest, fruit concentrations of N, P, K, and S were not affected by plant population, but increased linearly as N rate increased from 180 to 360 kg·ha^-1.  Fruit mineral uptake, however, increased linearly as population increased, but was not influenced by N rate. Efficiency of N utilization (N used/N applied) increased linearly as plant population increased, but decreased linearly as N rate increased. Fruit yield in all categories increased linearly as plant population increased.  Yield of USDA Fancy pepper fruit was not influenced by N application rate, but fruit yields in all other categories decreased as N rate increased. Maximum yield and N-use efficiency for 'Galaxy' bell pepper are achieved with N applied at 180 kg·ha^-1 with a plant population of 61500 plants·ha^-1.