EFFECTIVENESS OF USING ARBUSCULAR MYCORRHIZAL FUNGI AND COMPOST TO INCREASE GOGO RICE PRODUCTION IN SUBOPTIMAL LANDS

Abstract

The expansion of upland rice cultivation into suboptimal lands, particularly Ultisols, represents a strategic approach to increasing national rice production. However, low soil fertility, acidic pH, and limited nutrient availability constrain productivity in such environments. This study aimed to evaluate the effectiveness of Arbuscular Mycorrhizal Fungi (AMF) and compost application in improving the growth and yield of upland rice (Inpago 12) cultivated on Ultisol soils in Deli Serdang and Langkat, North Sumatra. A factorial randomized block design with three factors, AMF dosage (0–600 spores), compost rate (0–5 t ha⁻¹), and location that was implemented with three replications (150 experimental units). Soil analysis confirmed acidic conditions with low nutrient status typical of Ultisols. Five AMF taxa were identified with root colonization ranging from moderate to very high (46.67–100%). ANOVA results revealed that location significantly affected most growth and yield parameters, whereas AMF and compost treatments showed limited statistical effects. The most effective treatment combination was 450 spores with 2 t ha⁻¹ compost in Deli Serdang, which improved tiller number, biomass, and panicle production. These findings indicate that the effectiveness of AMF and compost application in Ultisols is highly site-specific and influenced by local soil characteristics.