Reduction of Synthetic Nitrogen Fertilizer Using Tithonia-Based Liquid Organic Fertilizer for Sweet Corn Production in Ultisols

Nitrogen (N) fertilization method is of great interest in nutrient management in sweet corn production. Sweet corn production areas in Indonesia have been increasingly extended to Ultisol land due to decline in the amount of arable land. Proper nitrogen management in Ultisols including the use of tithonia-based liquid organic fertilizer (LOF) as a way of reducing the use of synthetic N fertilizer need to be investigated. In this experiment, we aimed to determine the effects of various combinations of tithonia-based LOF and synthetic N on the growth and yields of sweet corn grown in Ultisols. This experiment was conducted from April to July 2018, in Bengkulu City, Indonesia at an elevation of 36 m above sea level and was arranged in complete randomized design with four replications. Treatments consisted of five combinations of LOF and synthetic N, i.e.  0 % LOF+100 % N, 25 % LOF+75 % of N, 50 % LOF+50 % N, 75 % LOF+25 % N, and 100 % LOF+0 % N. The results indicated that fertilizer combination composition significantly affected plant height, leaf greenness, husked ear weight, unhusked ear weight, and ear length of sweet corn, but did not affect leaf number and shoot dry weight. Overall, the use of 75% LOF in combination with 25% synthetic N produced similar results to 100% synthetic N.  It was concluded that the use of tithonia-based LOF reduced the use of synthetic N fertilizer in sweet corn production grown in Ultisols. This conclusion should be further evaluated for sweet corn production under field conditions in Ultisols.

Keywords: liquid organic fertilizer; sweet corn; synthetic N fertilizer; ultisols

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                                             E-mail: fahrurrozi@unib.ac.id