SULFATE AMMONIUM FERTILIZER ON THE OFF-SEASON PRODUCTION OF SNAKE FRUIT (Salacca sumatrana Becc.)

Sidimpuan snake fruit is one of the local specialties of Padangsidimpuan City in Sumatra. The fruit is known for its sweet, sour and astringent taste which differentiates it from Pondoh and Balinese snake fruit. However, snake fruit farmers have been experiencing an increasing failure rate of fruit-set during the off-season which has led to a decrease in production.   Use fertilization and drip irrigation in the off-season has been suggested as a solution. This research investigates the use of these to overcome the failure of fruit set to optimize production of Sidimpuan snake fruit throughout the year by determining the optimal dosage of ammonium sulfate fertilizer and drip irrigation for fruit set and production in the off-season. This research used a split-plot design with the main plot for drip irrigation and the subplot for ammonium sulfate. Observation parameters include the number of flower and fruit bunches, fruit set percentage and a nutrient analysis of the leaves. The results revealed that drip irrigation had a significant effect on the observed variables of fruit set and number of harvested fruit bunches.  Drip irrigation had a significant effect on the fruit set percentage and the number of harvested fruit bunches. The best combination of treatments was also discovered to be 400 g ammonium sulfate fertilizer per plant and drip irrigation 3000 ml/plant. The fertilization period of July-Sept gave an off season harvest that was able to match the fruit set percentage (10.76% difference) and number of fruit bunches that were formed (25.65% difference ) by the April-June fertilization for the on-season harvest demonstrating that drip irrigation and ammonium sulfate can overcome fruit set failure in Sidimpuan snake fruit during the off-season.