A humic acid improves growth of tomato seedling in solution culture

• Published in: Journal of plant nutrition Vol. 17; no. 1
• Main Authors: David, P.P, Nelson, P.V, Sanders, D.C
• Format: Journal Article
• Language: English
• Published: 1994
• Subjects: ABSORCION DE SUSTANCIAS NUTRITIVAS; ABSORPTION DE SUBSTANCES NUTRITIVES; ACIDE HUMIQUE; ACIDO HUMICO; CONTENIDO MINERAL; LYCOPERSICON ESCULENTUM; MEMBRANA; MEMBRANE; MINERALES; MINERAUX; NUTRICION DE LAS PLANTAS; NUTRITION DES PLANTES; PERMEABILIDAD; PERMEABILITE; PLANTULAS; PLANTULE; RACINE; RAICES; SOLUCIONES NUTRITIVAS; SOLUTION NUTRITIVE; TALLO; TENEUR EN ELEMENTS MINERAUX; TIGE
• ISSN: 0190-4167; 1532-4087
• DOI: 10.1080/01904169409364717

The effects of humic acid (HA) on nutrient accumulation and growth of tomato seedlings were evaluated in a solution of limited nutrient availability in a greenhouse. HA additions were made to the nutrient solution at rates of 0, 640, 1280, or 2560 mg/L. The addition of 1280 mg/L HA produced significant increases in shoot accumulation of P, K, Ca, Mg, Fe, Mn, and Zn as well as increased accumulation of N, Ca, Fe, Zn, and Cu in roots. Fresh and dry weights of roots were also increased. However, on comparing nutrient accumulation in plants treated with 1280 mg/L HA and those given an additional supply of nutrients equivalent to those supplied by HA at the 1280 mg/L rate, shoots accumulated more N, P, K, Fe, and Cu, while roots accumulated more K and Ca. Therefore these increases do not appear to be associated with nutrients contained in HA. Electrolyte leakage, as an indication of membrane permeability, did not differ as a consequence of HA additions. However, electrolyte leakage correlated positively with HA rate. A shift in solution pH from 5.8 to 7.0 had no effect upon on nutrient accumulation or growth of tomato seedlings. The interaction of pH and addition of HA was not significant