Effects of nitrogen fertilizer (urea) on cabbage (Brassica oleracea L. var. capitate) performance on Ithaca sandy loam soil

This study evaluated the impact of different nitrogen (N) fertilizer application rates on the growth and yield performance of cabbage (Brassica oleracea L. var. capitata) grown on Ithaca sandy loam soil. The experiment employed a Randomized Complete Block Design (RCBD) comprising four nitrogen treatments: 0 kg N/ha (control), 150 kg N/ha, 240 kg N/ha, and 291 kg N/ha, with three replicates per treatment. Urea (46% N) served as the nitrogen source and was applied in split doses to minimize volatilization and leaching. Key agronomic parameters assessed included cabbage head weight (kg) and head diameter (cm), which are critical indicators of marketable yield. Statistical analysis revealed a significant positive correlation between nitrogen application rate and both yield attributes, with the 291 kg N/ha treatment producing the highest mean head weight and head diameter. These findings indicate that increased nitrogen availability enhances cabbage biomass accumulation and head development under the given soil conditions. However, potential environmental and economic implications of high nitrogen usage necessitate further investigation. It is recommended that subsequent studies evaluate nitrogen responses under varying edaphic conditions, include nitrogen rates exceeding 291 kg N/ha, and account for seasonal variability, particularly rainfall, which may influence nitrogen uptake efficiency. Additionally, testing multiple cabbage cultivars could uncover genotype-specific nutrient responses, ultimately informing optimized and sustainable fertilizer management practices.