Foundation and validation of diagnosis and recommendation of integrated system norms for evaluating nutrient status of pineapple plants (Ananas comosus L.)

This study aimed to (i) establish the diagnosis and recommendation of integrated system (DRIS) norms for the evaluation of nutrient status in pineapple plants and (ii) validate the reliability of DRIS norms. Eighty-six leaf samples at +1 (E leaf) and +3 (D leaf) positions were collected from 86 pineapple fields cultivated in acid sulfate soils at the leaf development stage. Results indicated that DRIS norms established for pineapple included 22 and 30 pairs of nutrient ratios at E and D leaf positions, respectively. The validation for the reliability showed that founded DRIS norms were reliable and suitable for assessing the nutrients status of pineapple. Based on the fertilizer omission plot technique, DRIS indices of N, Ca, and Mg in the treatments without N, Ca, or Mg fertilizer, respectively, were less excessive than those in the treatment with full NPKCaMg fertilization at both leaf positions, meaning that the DRIS norm is reliable. Both leaf positions can be used to diagnose N, K, Ca, and Mg nutrients status