Influence of Nitrate Fertilizer on Macronutrient Contents of Celery Plants on Soil-Less Culture

Abstract

Two rates of nitrate (NO₃) supply were used in production of celery plants (Apium graveolens L., cv. ‘Istar’) grown on perlite or coir substrates. A standard nitrogen dose (CN) was compared to a concentration that was 25% less (RN). Other nutrients were supplied at the same level for both treatments. Plants were harvested after 85 d of growth, divided into leaves, petioles, internal stalks, basal disc, and roots, and the macronutrient contents [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S)] were analyzed. The ratios between elements (Na/K, Mg/Ca, and N/P) were also determined at the whole plant level. Commercial yield was statistically the same for CN and RN treatments. Nutrient content for plants cultivated on coir were slightly higher than those on perlite. Petioles and leaves showed the highest accumulation of K, Ca, and Mg; the roots also had similar high levels. The basal disc and internal stalks tended to accumulate S. Nitrogen and P were uniformly distributed throughout the plant. Roots showed the highest accumulation of Na. On a whole plant basis, the nutrient contents for CN and RN were almost the same, with only a slightly higher N concentration for CN. Within the edible fraction (petioles + internal stalks), the RN treatment resulted in a higher concentrations for all the nutrients except N, compared to CN. Thus, celery plants cultivated with a nitrogen dose 25% lower than that commonly used by producers had a balanced nutrient content and were safer for consumers.