ABSTRACT
Nitrogen sources and leveis applied to nonirrigated Pedro Jiménez grape - vines. IV. Effects over total-N and NO3-N contents of petioles

Arturo Lavín A.1 y Jorge Valenzuela B.2
 

From 1973 to 1977, at the Cauquenes Experimental Station (INIA-Chile), annua( petiole samples were collected at full bloom, from nonirrigated Pedro Jiménez vines, fertilized with Chilean nitrate, urea and ammonium nitrate, at different doses. Total-N and NO3-N were analyzed. Nitrate concentrations were higher with Chilean or ammonium nitrate, than with urea, in ihe first year measurements. For the overali period, differences were found dueto N sources, both for NO3-N and total-N. Total-N presented less variability then NO3-N in each year (except 1976), but variability among years affected both parameters, which should be taken into account, when estimating N nutrition of vines under similar conditions.

Keywords:
1 Subestación Experimental Cauquenes (INIA), Casilla 165, Cauquenes, Maule, Chile.
2 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago, Chile.