ChileanJAR

At the Cauquenes Experiment Station, a field experiment was done with Pedro Jiménez grapevines (Vitis vinífera L.) planted in 1970, under unirrigated conditions. From 1972 to 1981, annually, three sources of N (Chilean nitrate, urea and ammonium nitrate) were applied. AII of them, in three doses of N: 37.5, 75.0 and 150.0 u./ha. Results showed that plants reacted only to ammonium nitrate, consistently during the first years, improving growth and yield. Trunk circumference was the only other variable that also reacted consistently to this N source. Plants did not show a clear response to higher doses of N, and 37.5 u./ha were adequate to promote growth and yield, under the unirrigated conditions of the area.