ABSTRACT


J. DOMINGO GODOY H.1, FEDERICO KOCHER G.2 Y AURELIO VILLALOBOS P.3
 
Nitrogen concentration standards for Mountain Papaw (Carica candamarcensis, Hook. f). were determined under greenhouse conditions.The plants were grown on sand culture, and the nitrogen levels were: 10 - 60 - 110 - 160 - 210 - 410 - 610 - 810 ppm. as ammonium nitrate.The following measurements were taken: growth as plant height, trunk diameter and number of leaves. At the end of the experiment whole mature leaves, roots and top were weighed.Tissue sampling for analyses were made after 75-115-155 days of treatment.Conclusions:The sampled tissue (petioles 9-10-11-12-13) is a good indicator of the plant nitrogen status.Nitrogen in petioles is directly related to the nutrient solution concentration this element. in Growth in height, number of leaves, trunk diameter, sample weight, total weight of roots and top increased directly with nitrogen content in petioles to a point where no detectable changes were noticed. Nevertheless, the largest nitrogen concentrations in pêtioles were detrimental on diameter, sample weight, root and top weight. The nutrient standards proposed are: deficient: less than 1,4 (visual deficiency symptom) low: 1,4 to 1,7 optimum: 1,7 to 2,0 "Critical nitrogen concentration" high: 2,0 to 4,0 excess: more than 4,0% of total nitrogen in the petioles (Symptoms that seem be an excess).
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1 Parte de la Tesis presentada a la Escuela de Agronomía de la Universidad de Chile por J. Domingo Godoy H., como uno de los requisitos para optar al título de Ingeniero Agrónomo.2 Ingeniero Agronómo, Ph. D., profesor de la Cátedra de Fruticultura General, Escuela de Agronomía, Universidad de Chile. Coordinador línea Fruticultura, Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias por convenio U. de Chile-Instituto.3 Ingeniero Agrónomo, Proyecto Fruticultura, Estación Experimental La Platina, Instituto de Investigaciones Agrope