Inorganic fertilizers efficiency with using the liquid organic fertilizer to increase the cabbage yield (Brassica oleracea var. capitata L.)

Abstract

Using organic materials as fertilizer has contributed a lot to protecting the environment and the future of human life through sustainable agriculture. Local resources are used in such a way that synthetic nutrients can be reduced as low as possible. This study aims to determine the effect of liquid organic fertilizer (LOF) on cabbage yield with inorganic fertilizers' efficiency. The research was conducted in Berastagi experimental farm, Karo regency, with the soil type and altitude of 1,340 m asl, which began from July - September 2018. The design used was a randomized block design consisting of 16 treatments with three replication. The treatments tested were: A. Without inorganic fertilizer + LOF 1, B. 25% inorganic fertilizer + LOF 1, C. 50% inorganic fertilizer + LOF 1, D. 75% inorganic fertilizer + LOF 1, E. 100% inorganic fertilizer + LOF 1, F. Without inorganic fertilizer + LOF 2, G. 25% inorganic fertilizer + LOF 2, H. 50% inorganic fertilizer + LOF 2, I. 75% inorganic fertilizer + LOF 2, J. 100% Inorganic Fertilizer + LOF 2, K. Without inorganic fertilizers + LOF 3, L. 25% inorganic Fertilizer + LOF 3, M. 50% inorganic Fertilizer + LOF 3, N. 75% inorganic Fertilizer + LOF 3, O. 100% Inorganic Fertilizer + LOF 3, P. 100% Inorganic Fertilizer + without LOF (Control). The results showed that, in general, the application of liquid organic fertilizer for rabbit urine, fish fertilizer, and fish teillation could stimulate the growth and yield of cabbage better than inorganic fertilizers. Applicationthe liquid organic fertilizer can increase theheight growth of cabbage was 0.67 - 0.88%, plant diameter was 0.33 - 2.56%, crop weight per plant was 5.14 - 5.84%, production per plot was 2.96 - 9.78%, and the crop ratio of 3.36 - 10.84% compared to the use of inorganic fertilizers.