Land use change alters carbon composition and degree of decomposition of tropical peat soils

Drainage associated with land use change in tropical peatlands has increased the rate of decomposition of peat soils and contributed to CO2 emissions. Increased decomposition may result in changes in the composition of the soil organic carbon (SOC). We examined the carbon functional group composition and degree of decomposition of peat soils under five different land uses to understand the effects of changing management intensity on tropical peatland soils. Samples were collected from seven sites spanning five different land uses (forest, shrubland, fernland, revegetation, smallholder oil palm) at the Pedamaran peatland in South Sumatra, Indonesia. SOC composition, measured by Solid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy, was dominated by the alkyl carbon (C) functional group in managed peatlands. However, in the forest far from drainage canals, the SOC comprised predominantly O-alkyl C. The contributions of the functional groups ketone C, carbonyl C and O-aryl C were low and tended to occur in stable proportions throughout the soil profiles. Drainage and land use change significantly affected peat carbon chemistry. The effects were greatest under oil palm, where O-alkyl C had been depleted rapidly under aerobic conditions leading to a change in the dominant carbon functional group from O-alkyl C to alkyl C. Furthermore, our results indicate that the alkyl C:O-alkyl C ratio is a more useful and informative indicator of the degree of decomposition of peat soil than the traditionally used C:N ratio. This more nuanced understanding of the different types of carbon that make up tropical peat soils under different land uses can be applied to support peatland restoration. In particular, nutrient cycling and water availability are likely to be influenced by carbon functional group and degree of decomposition. In order to reduce fire risk and support Indonesia’s aspirations to manage the national forest estate as a net carbon sink, further research into the links between peat soil organic carbon chemistry, revegetation performance and new peat accumulation is recommended

Struktur dan Komposisi Vegetasi Hutan Bekas Tebangan di Rimbo Sekampung, Sumatera Selatan

Hutan Rimbo Sekampung (HRS) merupakan salah satu ekosistem hutan alam lahan kering yang tersisa di Sumatera Selatan. Penelitian ini bertujuan mendapatkan informasi tentang struktur dan komposisi tumbuhan penyusun hutan bekas tebangan di HRS. Pengambilan data dilakukan menggunakan metode jalur berpetak. Sebanyak 40 plot dibuat dalam empat jalur dengan panjang jalur 1.000 m dan jarak antar jalur 20 m. Di dalam jalur-jalur coba dibuat petak contoh berukuran 20 m x 20 m untuk pengamatan tumbuhan tingkat pohon, 10 m x 10 m untuk tingkat tiang, 5 m x 5 m untuk pancang dan 2 m x 2 m untuk anakan pohon dan herba. Total sebanyak 145 jenis tumbuhan (44 famili) berhasil diidentifikasi. Tumbuhan tingkat pohon didominasi jenis gerunggang (Cratoxyolon arborescens Bl.) (INP=44,16%), tumbuhan tingkat tiang didominasi oleh jenis sungkai (Peronema canescens Jack.) (INP=52,32%) sedangkan tingkat pancang serta anakan pohon dan herba didominasi oleh jenis marak (Macaranga tanarus (L.) Muell.Arg.) (INP=41,03% dan INP=25,49%). Jenis-jenis yang dijumpai dan mempunyai potensi ekonomi cukup tinggi sebagai kayu pertukangan antara lain gerunggang (Cratoxyolon arborescens Bl.), sungkai (Peronema canescens Jack.), laban (Vitex pubescens Vahl.), medang kuning (Litsea firma Hook P.) dan bayur (Pterospermum javanicum Jungh.

Differences in Tropical Peat Soil Physical and Chemical Properties Under Different Land Uses : A Systematic Review and Meta-analysis

Drainage and conversion of natural peatlands, which increases fire frequency, haze air pollution and carbon emissions, also affects the physical and chemical properties of peat soils. Although there has been continued interest in research on tropical peat soil properties, no attempt has yet been made to synthesise these results. We conducted a systematic literature review and meta-analysis of sixty-six papers published in English language academic literature to explore the current state of knowledge of peat soil properties of Southeast Asia and to compare physical and chemical peat properties (e.g. bulk density, carbon content, pH) under different land uses and depths. Most of these studies were undertaken in Indonesia (56.1%) and Malaysia (28.8%), where substantial tracts of peat soils occur. We extracted data from these papers to calculate the mean of each peat property and compare results between land uses and depths. Linear mixed-effects models were used to test the significance of land use and depth on each peat property. We found that bulk density (44 papers), carbon (C) content (43 papers), pH (42 papers) and nitrogen (N) content (39 papers) were the most widely reported, while other properties remain less studied. Bulk density, pH, phosphorus (P) and calcium (Ca) showed significant differences between land uses and depths. Fibre fraction, potassium (K), iron (Fe) and zinc (Zn) levels showed a significant difference between land uses only, while N differed significantly only between soil depths. Other physical properties such as hydraulic conductivity, porosity, woody fraction, amorphic fraction and chemical properties such as electrical conductivity (EC), C, ammonium (NH4+), nitrate (NO3−), available nitrogen (available N), magnesium (Mg), aluminium (Al), copper (Cu), manganese (Mn), sulphur (S) and silicon (Si) showed no significant differences between land uses or depths. This review identifies key research gaps, including underrepresented geographic areas and peat properties and highlights the need for standardised methodologies for measuring peat soil properties.</p

Three Years Post Fire Areas Natural Regeneration of Peat Swamp Forest in Merang, Musi Banyuasin District, South Sumatera

This study examines natural regeneration of tropical peat swamp forest after fire. The study area is located in Merang Peat Swamp Forest (PSF) in Musi Banyuasin District. Merang PSF is situated over a large peat dome that stores huge amount of carbon. 23 sample plots were established in the area burned in 2015. The regeneration of understorey, seedlings, and saplings was recorded in each plot. Meanwhile, peat depth and its maturity were identified to determine the soil characteristic of study area. After 3 years of fire, the area already covers densely by understorey mainly pakis udang (Stenochlaena palustris), pakis tanah (Nephrolepis exaltata), and resam (Gleichenia linearis) with depth of root zone reach about 40 cm in some plots. The native peat swamp species showed minimal regeneration during third years after fire due to understorey covering and limited number of surviving trees. The natural regeneration of woody species was dominated by bangun-bangun (Melicope glabra) and sepongol (Evodia sambuciana) which were calculated about 371 saplings/ha and 200 saplings/ha respectively. Those all two species also founded in the seedlings stage. The peat depth varied from 0.32 m to 4.71 m with peat maturity is dominantly hemic in the subsurface. This regeneration information provides useful indications for restoration options, which could be done by assisted natural regeneratio

Economic Analysis of of Micro Hydro Power Plant Development: A Case Study in Muara Enim Regency, South Sumatra

Micro Hydro Powerplant (MHP) is one form of water utilization in upper Musi watershed to generate electricity. This paper aims to analyse the feasibility of the development and management of self-help MHP to support forest resource conservations. Financial and economic analysis are applied to determine the feasibility of the development and management of the self-help MHP. The result indicates that the construction and management of the self-help MHP in the research area are not feasible, so that they do not guarantee the sustainability of the MHP in the long term period. Development and management of MHP will be financially feasible when it uses postpaid electricity tariff scheme of State Electricity Company (SEC) for power limit up to 450 VA, and economically feasible if it uses postpaid electricity tariff scheme for power limit (SEC) up to 1,300 VA. It is necessary to increase the capacity of the community both technical and economic aspects in the management of MHP for the sustainability of electricity supply from the MHP. Water utilization for the MHP increases the collective awareness to conserve forest resources

Analisis Spasial Tingkat Kerusakan Kawasan Suaka Margasatwa Padang Sugihan Sumatera Selatan

Kawasan Suaka Margasatwa Padang Sugihan merupakan habitat penting bagi gajah sumatera. Namun demikian kondisinya saat ini terus mengalami tekanan terutama akibat kebakaran, pembalakan liar, dan penguasan lahan oleh oknum masyarakat. Penelitian ini bertujuan untuk melakukan pemetaan tingkat kerusakan Suaka Margasatwa Padang Sugihan dan mengidentifikasi penyebab kerusakan sebagai bagian kegiatan perencanaan pemulihan ekosistem. Analisis kerusakan kawasan menggunakan sistem informasi geografis dengan metode skoring tumpeng susun dan pembobotan terhadap parameter-parameter yang berpengaruh terhadap kerusakan kawasan, yaitu tutupan lahan, frekuensi kebakaran, areal berkanal dan lahan gambut, sensivitas ekologi dan sensivitas sosial. Setiap parameter akan memiliki bobot yang berbeda berdasarkan pengaruhnya terhadap kerusakan kawasan dan kelangsungan hidup spesies kunci. Hasil penelitian menunjukkan kawasan dengan tingkat kerusakan berat seluas 13.219,60 Ha (15%), rusak sedang seluas 31.867,20 Ha (36%), dan rusak ringan seluas 42.555,91 Ha (49%). Areal yang mengalami kerusakan berat merupakan area yang diusulkan menjadi prioritas utama kegiatan pemulihan ekosistem. Kerusakan ekosistem di SM Padang Sugihan terutama disebabkan oleh kebakaran hutan yang terjadi secara berulang, pembalakan hutan, dan pembukaan kanal drainase. Ketiga faktor tersebut menyebabkan hilangnya masa gambut dan berkurang/ hilangnya komposisi vegetasi asli

Carbon Loss Affected By Fires On Various Forests And Land Types In South Sumatera

Forest and land fires are a high source of emissions in South Sumatera. In line with the national policy, South Sumatera Province commits in reducing emission, include emission from the forest and land fire. This research was aimed to assess carbon loss affected by fire in the year of 2015 that covered 3 districts in South Sumatera i.e Musi Banyuasin, Banyuasin, and Musi Rawas. The research was conducted by remeasurement of carbon stocks plots on 4 forests and land type i.e. secondary peat swamp forest, secondary dryland forest, bushes swamp, and forest plantation. Carbon stocks measuring are conducted on sample plots in a rectangular shape of 20 m x 50 m of size for various types of natural forest and a circle shape in the radius of 11.29 cm and 7.98 cm respectively for forest plantation of 4 years old. Furthermore, carbon stocks in each plot are measured for 3 carbon pools of above-ground biomass, deadwood and litter. The result shows that carbon loss was varying on each forest and land type. The largest number of carbon loss occur on secondary peat swamp forest of 94.2 t/ha that equivalent to the emission of 345.4 t CO2eq. The second largest of carbon loss occur on secondary dryland forest of 36.3 t/ha following by forest plantation and bushes swamp of 18.5 t/ha and 13.5 t/ha. The largest carbon loss on secondary peat swamp forest and forest plantation occur on above-ground biomass pool but secondary dry forest and bushes swamp occur on the dead wood pool