Arief Noor Rachmadiyanto1, Reni Lestari1*, Kartika Ning Tyas1, Mahat Magandhi1, Didi Usmadi2, Rizmoon N. Zulkarnaen3, Hendra Helmanto2, Frisca Damayanti1, Reza Ramdan Rivai1, Enggal Primananda2, Iin Pertiwi A. Husaini1, I Made Sudiana4, Safendrri K. Ragamustari5, Masaru Kobayashi6
1Research Center for Applied Botany, National Research and Innovation Agency (BRIN), Bogor, Jawa Barat, 16911, Indonesia
2Research Center for Biota System, National Research and Innovation Agency (BRIN), Bogor, Jawa Barat, 16911, Indonesia
3Research Center for Ecology, National Research and Innovation Agency (BRIN), Bogor, Jawa Barat, 16911, Indonesia
4Research Center for Applied Microbiology, National Research and Innovation Agency (BRIN), Bogor, Jawa Barat, 16911, Indonesia
5School of Government and Public Policy, Jl. Anyar, Hambalang, Sentul, Bogor, 16810, Indonesia
6Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
*Corresponding author’s email: reni.lestari@brin.go.id
Received: 30 March 2026 / Revised: 24 July 2026 / Accepted: 06 August 2026 / Published Online: 25 August 2026
Abstract
The feasibility of sorghum [Sorghum bicolor (L.) Moench] production as a renewable energy feedstock was evaluated through multi-cycle field trials on degraded tropical grasslands dominated by Imperata cylindrica in Indonesia. The study aimed to quantify the achievable yield levels and soil responses under different nitrogen (N) fertilizer rates, combined with or without compost and a microbial inoculant, at two contrasting sites representing moderately fertile and nutrient-poor soils. Nitrogen was confirmed to affect biomass production, grain yield, stem juice sugar content, and plant N content, whereas compost and the microbial inoculant had only limited effects. Maximum biomass yields reached 25–32 t ha–1 per cycle (50–64 t ha–1 year–1 with two annual crops), sufficient to meet the life-cycle assessment threshold for net greenhouse gas reduction through coal co-firing in power generation. In contrast, yields at the nutrient-poor site remained lower (16–24 t ha–1 per cycle). Successive sorghum cultivation decreased soil organic carbon, cation exchange capacity, and soil pH, although compost application mitigated these declines. These field results provide empirical benchmarks for evaluating the performance of sorghum-based energy systems on marginal tropical lands. They can support techno-economic and environmental modeling of low-carbon energy scenarios.
Keywords: Marginal land, Bioenergy, Feedstock, Nitrogen fertilizer, Sorghum
