The use of soil ameliorants and fertilizers to increase the yields of rice and maize in ultisols Lampung, Indonesia

Abstract

The Ultisols has high soil acidity, Al and Fe concentration and low organic matter, nutrients, base saturation, and CEC, that limit the growth of rice and maize. The research aimed to evaluate the effectiveness of the application of fertilizers, soil ameliorant, and their combinations to improve Ultisol productivity including to increase rice and maize crops yields. This research was conducted at the Taman Bogo experimental station, Lampung Timur District, for two growing seasons (GS-1 and GS-2) in 2019. Field experiment used randomized block design with eight treatments and three replications. The treatments were included control, recommendation dosage of fertilizers (for rice: 250 kg urea ha-1, 200 kg SP-36 ha-1, 75 kg KCl ha-1; for maize: 300 kg urea ha, 175 kg SP-36 ha-1, 100 kg KCl ha-1), and combination of the recommendation dosage of fertilizers, manure, biofertilizer, and rock phosphate. Recommendation dosage of fertilizer was determined using upland soil test kit (made by Indonesian Soil Research Institute). The result showed that soil ameliorant and biofertilizer application gave significant effect to improve soil chemical physic properties and plant yields.