SYNCHRONIZING DIAGNOSIS AND CORRECTION OF NITROGEN DEFICIENCY IN BARLEY GROWN IN SEMIARID ENVIRONMENTS

In field experiments conducted from 1986 to 1989, nitrogen (N) deficie ncy in barley crops was corrected with the same efficiency by applying N fertilizer at sowing or by broadcasting it at early tillering. Four plant tests for diagnosing and predicting N deficiency in barley were evaluated. Of these the basal stem nitrate-N test was best with a cal ibrated critical range of 12 000 to 15 000 mg kg(-1) when sampling was during early tillering.