Improvements of the DRIS-system and first experiences in grapevine nutrition with special consideration of the compositional nutrient diagnosis approach

摘要

Diagnostic recommendation and integrated system (DRIS) norms were successfully calculated for grapevines using long-term (1978-93) fertilizer trial data from 50 vineyards in the Rheingau area of Germany. Low- and high-yielding subsets were identified with different norms. New DRIS indices were calculated according to the compositional nutrient diagnosis (CND) on a leaf DW basis. The new DRIS indices were found to have advantages over the critical value approach (CVA). DRIS indices reflected the overall nutritional status of the plant, allowing a rational approach to data-logging and fertilizer recommendation. With CVA, there was a risk of overestimating any changes in leaf nutrient composition, regardless of whether they derived from exogenous orendogenous factors. With the proposed system, interpretation of leaf analysis could be fully automated.