Improving Rice (Oryza sativa L.) Productivity Using Coconut Shell Wood Vinegar and Trichoderma-Enriched Biochar in Suboptimal Soil

¹ Universitas Lancang Kuning, Department of Agrotechnology, 28261 Pekanbaru, Indonesia
² Universitas Lancang Kuning, Graduate School of Agriculture Sciences, 28261 Pekanbaru, Indonesia
³ Universitas Riau, Department of Chemical Engineering, 28293 Pekanbaru, Indonesia
⁴ Agriculture Research Center, Central Agricultural Pesticide Laboratory, 12618 Giza, Egypt
⁵ Center for Environmental & Sustainable Tropical Agricultural Research, 28261 Pekanbaru, Indonesia

^* Corresponding author: indra.purnama@unilak.ac.id

Abstract

Declining rice productivity in many regions of Indonesia has been linked to soil degradation and excessive reliance on synthetic pesticides, which adversely affect soil health and environmental sustainability. This study evaluated the effectiveness of coconut shell wood vinegar—a botanical pesticide rich in phenolic and acetic compounds—in combination with Trichoderma-enriched biochar as an integrated strategy to improve rice (Oryza sativa L.) growth and yield under suboptimal soil conditions. A factorial experiment was conducted using a completely randomized design (CRD) with three levels of wood vinegar (0%, 2%, and 4%) and three biochar treatments (6.25 kg plot^-1) with and without Trichoderma, replicated three times. The results revealed that the combined treatments significantly improved plant height, number of productive tillers, grain yield, and milling recovery (p < 0.05). The best plant height and thousand-grain weight were obtained with 4% wood vinegar alone, while the biochar-only treatment produced the highest number of productive tillers. In contrast, the combined application of 4% wood vinegar and Trichoderma-enriched biochar (P2T1) resulted in the highest grain yield and milling weight. These findings underscore the potential of integrating botanical biopesticides with microbial-enriched soil amendments to sustainably enhance rice productivity and soil quality, particularly in degraded or marginal tropical soils.