摘要：The objectives of this research were to determine the effect of natural materials added to the rice straw fermentation process; and to find the best formula for organic fertilizers to increase nutrient uptake, growth, and rice grain yield in newly opened and intensive lowland. The research was conducted at West Sumatra AIAT’s laboratory and lowlands at Dharmasraya Regency, West Sumatra Province, Indonesia from July to December 2017. The first research included three formulas of organic fertilizers and the second included six treatments produced from the first research. The results showed that increasing amount of titonia from 200 kg to 400 kg and rock phosphate from 5 kg to 20 kg per ton of rice straw increased compost’s nitrogen and phosphorus content of the compost from 1.22% to 1.36%, and from 0.75% to 1.68% respectively. Application of compost without inorganic fertilizers in newly opened lowland decreased 23% of yield and increased 4.7% yield when combined with inorganic fertilizers. The combined application of organic and inorganic fertilizers increased 10-12% yield and decreased 10% of yield without inorganic fertilizers in intensive lowland. Application of organic fertilizer without inorganic fertilizers not significantly influenced the growth. Combination of organic and inorganic fertilizers is the best way to increase lowland rice yield.
