Leaf nutrient levels in flue-cured tobacco; 2: nutrient concentrations in relation to grade index and crop value index [Philippines]
1987
Briones, A.M. | Abella, L.A. (Philippines Univ., Los Banos, College, Laguna (Philippines))
Leaf yield parameters of flue-cured tobacco cv Coker 254 and plant analysis data from 2 fertilizer experiments (N x P factorial; N x K factorial) conducted in various field sites in northwestern Luzon [Philippines] were subjected to multiple regression analysis. For each site, the dependent variables were grade index (GI)a and crop value index (CVI), the independent variables were N, P, K, Ca, Mg, and CI contents of the youngest fully expanded leaf samples at button stage. The combined effects of the leaf nutrient elements on GI or CVI, as expressed by multiple regression coefficient (R), were found to be significant for most of the sites. Partial regression coefficients have magnitudes and signs that indicated location-specific relationships for practical implications, the most notable of the independent variables is nitrogen. Increasing leaf N content resulted in reduction of GI but it caused an increase in CVI. This implies that N fertilizer management for profitable tobacco production should not be designed either for high leaf grade or optimum yield but for both.
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