PUTU OKI BIMANTARA
Department of Agroecotechnology, Faculty of Agriculture, Universitas Udayana. Jl. PB. Sudirman, Denpasar 80231, Bali, Indonesia

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Compost maturity and plant response in community-based compost systems from Bali, Indonesia PUTU OKI BIMANTARA; I MADE ADNYANA; NI LUH KARTINI; I GUSTI NGURAH MADE PRABHASWARA
Asian Journal of Agriculture Vol. 10 No. 1 (2026)
Publisher : Smujo International

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/asianjagric/g100176

Abstract

Abstract. Bimantara PO, Adnyana IM, Kartini NL, Prabhaswara IGNM. 2026. Compost maturity and plant response in community-based compost systems from Bali, Indonesia. Asian J Agric 10 (1): g100176. https://doi.org/10.13057/asianjagric/g100176. This present study focused on determining the quality of compost, its maturity, and the reaction of plants to different types of compost produced by community-run and municipal waste disposal centers in Bali, Indonesia. Compost samples were gathered from four locations of waste disposal facilities, specifically from Panca Lestari, Padang Tegal, PDU DLHK Denpasar, and Kedonganan. The quality of compost was determined according to the SNI 19-7030-2004, consisting of organic carbon, total nitrogen, C/N ratio, organic matter, pH, moisture, and physical aspects. The experiment was conducted in a greenhouse using Ipomoea reptans in factorial randomized block design with four levels of compost treatments, i.e., K0=control, K1=1.0 kg polybag-¹, K2=1.3 kg polybag-¹, and K3=1.6 kg polybag-¹. The data related to plant growth was analyzed using a Linear Mixed Model, while final biomass and post-harvest soil analysis were conducted using Factorial ANOVA. There were differences in the quality of compost from different sources. While Padang Tegal met all the SNI requirements, others failed to meet certain criteria including high levels of organic carbon, organic matter, pH value, C/N ratio, or foreign particles. Organic carbon ranged from 26.13% to 34.51%, total nitrogen from 0.72% to 2.84%, and C/N ratio from 11.67 to 47.55. Plant growth responses were strongly time-dependent. Compost dose significantly affected plant height, number of leaves, and stem diameter, whereas SPAD response was influenced by compost source and its interactions with dose and observation time. However, fresh and dry biomass were not significantly affected by compost source, dose, or their interaction. Post-harvest soil organic carbon, total nitrogen, and C/N ratio were significantly affected by compost source, dose, and their interaction. These findings indicate that composts from local waste management facilities differ in quality and produce time-dependent soil-plant responses. Further studies with larger replication and direct measurements of nutrient dynamics are needed before broader agronomic recommendations can be made.
Soil fertility evaluation and crop development in Kubutambahan Sub-district, Buleleng District, Indonesia MADE SRI SUMARNIASIH; PUTU PERDANA KUSUMA WIGUNA; PUTU OKI BIMANTARA; I NENGAH KARNATA
Asian Journal of Agriculture Vol. 10 No. 1 (2026)
Publisher : Smujo International

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/asianjagric/g100172

Abstract

Abstract. Sumarniasih MS, Wiguna PPK, Bimantara PO, Karnata IN. 2026. Soil fertility evaluation and crop development in Kubutambahan Sub-district, Buleleng District, Indonesia. Asian J Agric 10 (1): g100172. https://doi.org/10.13057/asianjagric/g100172. The productivity of agricultural land is strongly influenced by soil fertility, yet detailed and spatially explicit assessments remain limited in many parts of Bali despite its diverse agroecosystems. This study assessed soil fertility in Kubutambahan Sub-district, Buleleng District, Bali, Indonesia, by delineating Homogeneous Land Units (HLUs) using GIS-based spatial analysis and conducting representative soil sampling. Seven HLUs were analyzed for key soil chemical properties, including organic C, total P₂O₅, total K₂O, Cation Exchange Capacity (CEC), Base Saturation (BS), and pH, and fertility status was determined following national evaluation guidelines using the principle of the most limiting factor. The results indicate that soil fertility across the district is predominantly low to moderate, with organic carbon levels (1.33-1.71%) consistently identified as the most critical limiting factor. Approximately 68.2% of the area (8,380 ha) was classified as low fertility, while the remaining 31.8% (3,908 ha) exhibited medium fertility. Low organic matter, low CEC, and, in some areas, very low BS were the primary causes of reduced fertility, despite generally adequate levels of phosphorus and potassium. Statistical analysis showed that organic carbon was significantly correlated with CEC (r = 0.49, p < 0.05) and base saturation (r = 0.65, p < 0.01), confirming its key role as a controlling factor of soil fertility. These findings highlight organic carbon as the primary limiting factor and emphasize the need for HLU-based, site-specific management strategies focused on organic matter restoration to enhance soil fertility and agricultural productivity in the study area. This study provides the first spatially explicit soil fertility assessment at the sub-district scale in Kubutambahan and highlights the need for HLU-based, site-specific management strategies emphasizing organic matter restoration to support sustainable agricultural productivity.