EFFECT OF ORGANIC AND INORGANIC FERTILIZERS ON SOYBEAN (Glycine max L.) GRAIN YIELD IN DRY LAND OF INDONESIA

Abstract

Increasing soybean (Glycine max L.) production in dry land can be done through intensification using organic and inorganic fertilizer. The aim of the study was to evaluate the optimization use of organic and inorganic NPK fertilizers on soil and soybean productivity on dry land. The experiment was arranged in a randomized complete block design with three replications on dry land in Gresik, East Java, Indonesia. The treatments evaluated were 12 dosage combinations of ZA (ammonium sulphate), SP-18 (super phosphate-18), KCl (potassium chloride), and chicken manure. The study was conducted on dry land without and with 5,000 kg cow manure/ha. The soybean seed used in this research was Argomulyo. The results showed that (1) application of 5,000 kg cow manure/ha increased the yield of Argomulyo soybean variety by 0.21 t/ha (9%), (2) application of 100 kg KCl/ha + 50 kg ZA/ha + 100 kg SP-18/ha + 5,000 kg cow manure/ha, and 50 kg ZA/ha + 2,500 kg chicken manure/ha + 5,000 kg cow manure/ha increased soybean yield by 0.95-1.38 t/ha (50-74%), (3) application of 100 kg KCl/ha increased P uptake by 68%, Ca uptake by 60%, and Mg uptake by 54% compared to without fertilizer, (4) application of 50 kg KCl/ha + 2,500 kg chicken manure/ha increased N uptake by 48%, application of 50 kg ZA/ha + 100 kg SP-18/ha increased K uptake by 117%, and application of 50 kg ZA/ha increased Ca uptake by 60% compared without fertilizer, and (5) application of 5,000 kg cow manure/ha improved the physical properties of the soil by reducing soil bulk density by 7% and soil penetration by 37% and increasing soil permeability of 2.20 cm/hour from 1.78 cm/hour to 3.98 cm/hour. Soybean cultivation of the Argomulyo variety on dry land in Gresik requires the addition of organic cow manure 5000 kg/ha plus ZA fertilizer 50 kg/ha + chicken manure 2500 kg/ha or ZA fertilizer 50 kg/ha + SP-18 100 kg/ha + KCl 100 kg/ha to increase yield 0.95–1.38 t/ha and improve soil physical fertility. This study gives the information that the use of organic and inorganic fertilizer is an alternative technology that is required to maintain and increase the productivity of soybean and soils in dry land to support sustainable soybean cultivation.