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LAJU DEKOMPOSISI DAN PRODUKSI BIOMASSA SERESAH TUMBUHAN BAWAH DI PERKEBUNAN KELAPA SAWIT PADA SISTEM LORONG NVI( NATURAL VEGETATION INTERROW ) DAN ISP (INTERROW SENDLING PLANTING)

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RIMA PUTRI KERTAMUDA. Decomposition Rate and Litter Biomass Production of Understory Plants in Oil Palm Plantation under NVI (Natural Vegetation Interrow) and ISP (Interrow Seedling Planting) Systems (Supervised by NUNI GOFAR). Oil palm plantations represent one of the dominant tropical agroecosystems that shape land use in Indonesia. Beneath the oil palm canopy, various understory plant species grow and contribute to ecosystem stability through litter production, which serves as an important source of organic matter and nutrients for the soil. This study aimed to determine the types and production of understory litter biomass, the litter decomposition rate, and the relationship between oil palm stand density and understory biomass under two interrow management systems, namely Interrow Seedling Planting (ISP) and Natural Vegetation Interrow (NVI). The research was conducted from September 2025 to January 2026 in a four year old oil palm plantation owned by PT Kenawan Agro Sejahtera, located in Burai Village, Tanjung Batu District, Ogan Ilir Regency, South Sumatra Province. Sampling was carried out using a random sampling method within 1 m × 1 m plots. A total of five plots were used to observe litter decomposition with three replications in each interrow system, while five additional plots were used to measure understory biomass production in each system. Litter decomposition was observed using the litterbag method (14 × 20 cm) containing 100 g of initial litter weight, which was placed in the field for six weeks with observation intervals every two weeks (week 2, week 4 and week 6) to capture the dynamics of organic matter decomposition in understory vegetation. Understory biomass production was measured by harvesting vegetation in the plots at week 2 and week 6, followed by oven drying to obtain oven dry biomass. Data analysis included graphical analysis of litter biomass reduction, calculation of the percentage of biomass loss during decomposition and estimation of the decomposition constant (k) using the exponential model of Olson (1963). Identification of understory plant species and calculation of biomass production were also conducted. The Sørensen similarity index was used to evaluate the similarity in species composition between the two interrow systems. Differences in the decomposition rate constant (k), understory biomass production and percentage of litter mass loss between interrows were analyzed using the Independent Samples T-Test at a 5% significance level, while the relationship between oil palm stand density and understory biomass was analyzed using Pearson correlation analysis. The results showed that litter biomass decreased most rapidly during the initial stage of decomposition, particularly within the first two weeks. The percentage of biomass loss during the observation period was higher in the NVI system (83.85%) compared with the ISP system (79.80%); however, the t-test results indicated that the difference was not statistically significant. The decomposition rate constant (k) also tended to be higher in the NVI system than in the ISP system, although the difference was not significant. In contrast, understory biomass production showed a significant difference (p < 0.05), where the NVI system produced higher biomass than the ISP system. Identification of understory plant species indicated that the ISP system had greater species diversity than the NVI system, although the Sørensen similarity index showed similarity in vegetation composition between the two interrow systems. Furthermore, Pearson correlation analysis indicated that oil palm stand density had no significant relationship with understory biomass, suggesting that biomass variation was more influenced by vegetation composition and environmental conditions within each interrow management system. Keywords: Decomposition Rate, Litter Biomass, Interrow System, Oil Palm, Understory Vegetation.

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Detail Information

Series Title

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Call Number

T1944122026

Publisher

Indralaya : Prodi Ilmu Tanah, Fakultas Pertanian Universitas Sriwijaya., 2026

Collation

xvii, 221 hlm.; ilus.; tab.; 29 cm.

Language

Indonesia

ISBN/ISSN

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Classification

581.507

Content Type

Text

Media Type

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Carrier Type

-

Edition

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Subject(s)

Prodi Ilmu Tanah
Ekologi Tumbuhan

Specific Detail Info

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Statement of Responsibility

TUTI

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