Jorge Valenzuela B.2, Aurelio Villalobos P.1 y Federico Kocher G.2

Salitre and sodium nitra te were used as sources of nitrogen for strawberries grown in sand culture. Both sources were applied alone and in combination with ammonium as NH4OH. Each of these fertilizer materials was applied at arate of 50, 150 and 350 ppm. of nitrogen in the solution. Salitre plus ammonium resulted in the highest yield weights of fresh and dry leaves as well as the highest yield weights of fresIl and dry roots, and the best growth was obtained with a concentration of 150 ppm. of nitrogen. Total-N, nitric-N and Na content in tIle leaves were increased when nitrogen and sodium increased. The contrary was observed for organic-N and potassium. Also a parcial replacement of potassium by sodium was found. Leaves showing progresive marginal necrosis were present in plants treated with the highest nitrogen concentration (150 and 350 ppm. of nitrogen), specially when ammonium was not included. The results suggest that tIle marginal leaf necrosis are more related to nitra te concentrations over 1% dry weight than sodium accumulation is.

1 Ingeniero Agrónomo, Proyecto Fisiología Vegetal, Estación Experimental La Platina Instituto de Investigaciones Agropecuarias
2 Ingeniero Agrónomo, Ph. D., Profesor de la Catedra de Fruticultura General de la Facultad de Agronomía de la Universidad de Chile, Proyecto Fisiología Vegetal del Instituto de Investigaciones Agropecuarias: por convenio Escuela de Agronomía·Instituto