Effect of NPK Fertilization Method on the Physiology and Fruit Products of Myristica fragrans in North Maluku, Indonesia

Aims: The objective of this study was to determine the optimal fertilizing method and NPK fertilizer dosage for plant physiology and nutmeg yield.

Study Design: The experimental design was a completely randomized block design (CRBD) in a 4x3 factorial arrangement with three replicates. The first factor was four NPK fertilizer doses: 1, 1.5, 2.0, and 2.5kg NPK (15:15:15)/tree/year. The second factor was the manner of fertilizer application: (1) fertilized in spot, (2) fertilized in-furrow trenches trunked and (3) fertilized in hole.

Place and Duration of Study: The research was conducted in Tobelo North Halmahera (1°44'45.3"-1°44'54.4" N, 127°59'54.4"-127°59'53.2" E), North Maluku, Indonesia from January 2019 to May 2020.

Methodology: The nutmeg trees used was 30 years old. The population of trees plants in the study area was 40 trees. Observation parameters on leaves are chlorophyll a, b and total, nitrate reductase activity (NRA), N, P, K, proline content, number of young and old fruits.

Results: The fertilization treatment with the fertilizer application method into the crack/hole fertilizer with a dose of 2.5 kg NPK significantly produced high levels of chlorophyll a, chlorophyll b, total chlorophyll of leaves and old fruit. The number of old fruits is positively correlated with chlorophyll a content (0.615*), chlorophyll b (0.663*), total chlorophyll (0.634*) and number of young fruits (0.748 **). The application of fertilizer hole produces plants that recover quickly from drought stress, as evidenced by the highest proline content.

Conclusion: NPK fertilization using the hole method and at doses of 2.0-2.5 kg/tree/year are recommended for improving plant physiology and yield.