PRELIMINARY DRIS NORMS FOR BANANA

Diagnostic nutrient norms for banana using the critical value approach have been established in different countries under a wide range of en vironmental conditions. Because these norms were identified through a curve representing the relationship of plant composition and yield, th eir application becomes limited to the conditions from which they were established. To minimize the effect of environment and ensure that no rms would have a wider application, the Diagnosis and Recommendation I ntegrated System was used to establish nutrient norms for banana. A da ta bank consisting of 915 observations from 26 published and unpublish ed sources was assembled. DRIS norms were established from the high yi elding population with a yield >70 t/ha, and compared with critical va lues obtained from published sources. Except for K and its ratios and products with other nutrients, DRIS norms were very similar to the ave rage critical values. The validity of DRIS norms and their superiority over the critical values in making correct diagnosis were partly conf irmed in a single fertilizer experiment but further testing in field f actorial experiments is needed.