| dc.description.abstract | Maize is one of the most important crops, besides wheat and rice. The increasing demand for maize should be balanced by the increase of production of maize. Therefore, one of the efforts is to improve soil fertility. One way to improve soil fertility is by evaluating the nutrients content in the leaf tissue leading to diagnose nutrient deficiency in the soil. It could be done by Diagnosis Recommendation Integrated System (DRIS) method. The objectives of this research were 1) to determine the DRIS and CND norms, 2) to assess the nutrient status of maize using DRIS method, 3) to compare DRIS method with critical nutrient level method, nutrient sufficiency range method and Compositional Nutrient Diagnosis (CND) method and 4) to reveal correlation value between DRIS method and CND method. The research consisted of 36 samples of high subpopulation and 148 samples of low subpopulation. These two populations were significantly different in all nutrient ratios except Ca/Mg and KIP, tested by F-test and t-test. Norm DRIS were 8.9 for NIP, 1.2 for NIK, 5.33 for N/Ca, ILOO for NlMg, 7.99 for KIP, 4.71 for KlCa, 10.04 for KlMg, 0.59 for PICa, 1.27 for PlMg and 2.26 for CalMg. Norm CND were 0.41 for N, -1.77 for P, 0.26 for K, -1.23 for Ca and -1.98 for Mg. Progressively diagnosis to nutrient concentration in DRIS method showed that the change of production was followed by the change of nutrient index value. For example 8.70 kwlha (maize production in control treatment) to 50.15 kwlha (maize production in 300-200-150 treatment) was followed by the change of N index from -14 to 2, P index from -15 to 1 and K index from -10 to 1. The order of nutrient deficiency changed from P>N>K>Ca>Mg to Ca>P>N>K>Mg. The order' of nutrient deficiency could not be described by using critical nutrient level and nutrient sufficiency range methods. This methods showed only the values of nutrient deficiency level without shown the nutrient deficiency order. In addition, the increasing production was also indicated by the decrease of Nutrient Balance Index (NBI) value. For example 8.7 kwlha (maize production in control treatment) to 50.15 kwlha (maize production in 300-200-150 treatment) was followed by the change of NBI value from 79 to 17. The similar result was shown by CND method. The positive correlation (R2= 0.9245) between DRIS and CND method was revealed. Combination leaf fertilizer to conventional fertilizer improved production and nutrient content in maize than conventional fertilizer used only. The result suggested that DRIS method was better in evaluating the result of plant analysis than that of critical nutrient level and nutrient deficiency range. Moreover DRIS was positively correlated with CND method. | en |
