A cost-efficient method to assess carbon stocks in tropical peat soil

Estimation of belowground carbon stocks in tropical wetland forests requires funding for laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple analytical tools to assist belowground carbon estimation where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (kgC m<sup>−3</sup>; C<sub>d</sub>) as a function of bulk density (gC cm<sup>−3</sup>; <i>B</i><sub>d</sub>), which can be used to rapidly estimate belowground carbon storage using <i>B</i><sub>d</sub> measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (C<sub>d</sub> = <i>B</i><sub>d</sub> × 495.14 + 5.41, <i>R</i><sup>2</sup> = 0.93, <i>n</i> = 151) for soils with organic C content > 40%. As organic C content decreases, the relationship between C<sub>d</sub> and <i>B</i><sub>d</sub> becomes less predictable as soil texture becomes an important determinant of C<sub>d</sub>. The equation predicted belowground C stocks to within 0.92% to 9.57% of observed values. Average bulk density of collected peat samples was 0.127 g cm<sup>−3</sup>, which is in the upper range of previous reports for Southeast Asian peatlands. When original data were included, the revised equation C<sub>d</sub> = <i>B</i><sub>d</sub> × 468.76 + 5.82, with <i>R</i><sup>2</sup> = 0.95 and <i>n</i> = 712, was slightly below the lower 95% confidence interval of the original equation, and tended to decrease C<sub>d</sub> estimates. We recommend this last equation for a rapid estimation of soil C stocks for well-developed peat soils where C content > 40%

A cost-efficient method to assess carbon stocks in tropical peat soil

Estimation of belowground carbon stocks in tropical wetland forests requires funding for laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple analytical tools to assist belowground carbon estimation where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (kgC m⁻³; C[subscript d]) as a function of bulk density (gC cm⁻³; B[subscript d]), which can be used to rapidly estimate belowground carbon storage using B[subscript d] measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (C[subscript d] = B[subscript d] × 495.14 + 5.41, R² = 0.93, n = 151) for soils with organic C content > 40%. As organic C content decreases, the relationship between C[subscript d] and B[subscript d] becomes less predictable as soil texture becomes an important determinant of C[subscript d]. The equation predicted belowground C stocks to within 0.92% to 9.57% of observed values. Average bulk density of collected peat samples was 0.127 g cm⁻³, which is in the upper range of previous reports for Southeast Asian peatlands. When original data were included, the revised equation C[subscript d] = B[subscript d] × 468.76 + 5.82, with R² = 0.95 and n = 712, was slightly below the lower 95% confidence interval of the original equation, and tended to decrease C[subscript d] estimates. We recommend this last equation for a rapid estimation of soil C stocks for well-developed peat soils where C content > 40%

Local knowledge on landscape sustainable-hydrological management reduces soil co2 emission, fire risk and biomass loss in west Kalimantan Peatland, Indonesia

Astiani D, TaherzadehMJ, Gusmayanti E, WidiastutiT, Burhanuddin.2019. Local knowledge on landscape sustainable-hydrological management reduces soil CO2 emission, fire risk and biomass loss in West Kalimantan Peatland, Indonesia.Biodiversitas 20:725-731.Local knowledge in managing peatlands, especially in the area of peat hydrology, has been practiced through generations to manage peatlands for agriculture and small scale gardens. Farmers in West Kalimantan have developed the way to conserve water by making simple dams using soil or woody plants to hold water from the peat upstream areas on small channels or rivers. To reduce puddles during rain or tides, people make small trenches, so-called parit cacingin the middle of the larger channel. The trench cross-section size is ~30-40 cm2. This channel can maintain the peat waterlevel to the extent of the depth of the channel. These channels, at the same time, are useful, for a clear, easy land ownership border for one farmer family land. The results of CO2 emissions assessment at various water levels on the peatland landscape demonstrate that the landscape which surrounded by the parit cacingtrenches can maintain lower CO2 emissions compared to the one that has deeper water levels. The knowledge to develop this channel has also reduced the risk of peatland fire hazard and the amount of peat biomass loss on a fire event. An assessment on the effect of water level on the loss of peat biomass when burned, reduce 30-78% loss risks if compared to water table depth of 60-80cm, which is assumed as general practices on peatland recently.The practices of the knowledge on peatlands hydrology management can reduce the risk of peatland soil CO2 emission as well as loss of peat mass through decomposition and during peat fires

Pengaruh Lama Perendaman Sabut Kelapa Sebagai Pupuk Cair Terhadap Pertumbuhan Dan Hasil Tanaman Ubi Jalar

Penelitian ini bertujuan untuk mengetahui pengaruh lama perendaman sabut kelapa terbaik terhadap pertumbuhan dan hasil tanaman ubi jalar. Penelitian ini menggunakan metode eksperimen lapangan dalam bentuk faktorial dengan Rancangan Acak Kelompok (RAK) yang terdiri dari satu faktor yaitu lama perendaman (P) yang terdiri dari 5 taraf yaitu p0 (1 hari), p1 (7 hari), p2 (14 hari), p3 (21 hari) dan p4 (28 hari). Setiap perlakuan terdiri dari 5 ulangan. Setiap ulangan terdiri dari 5 sampel, sehingga terdapat 25 satuan perlakuan dan 375 tanaman. Variabel yang diamati dalam penelitian ini yaitu berat kering tanaman bagian atas (g), jumlah umbi per tanaman (umbi), berat segar umbi per tanaman (g), berat segar umbi per petak (g). Hasil penelitian lama perendaman sabut kelapa sebagai pupuk cair berpengaruh nyata terhadap variabel jumlah umbi per tanaman, berat basah umbi per tanaman dan berat basah umbi per petak. Sedangkan lama perendaman sabut kelapa sebagai pupuk cair tidak berpengaruh nyata terhadap variabel berat kering tanaman bagian atas. Perlakuan lama perendaman14 hari (p3) memberikan rerata tertinggi pada variabel jumlah umbi per tanaman yaitu 3,24 buah, variabel berat segar umbi per petak yaitu 2804,83 g dan berat segar umbi per tanaman yaitu 186,98 g. Perlakuan lama perendaman sabut kelapa 1 hari (p0) memberikan rerata terendah terhadap ketiga variabel namun memberikan rerata tertinggi pada variabel pengamatan berat kering tanaman bagian atas

CH4 and N2O emissions from smallholder agricultural systems on tropical peatlands in Southeast Asia

There are limited data for greenhouse gas (GHG) emissions from smallholder agricultural systems in tropical peatlands, with data for non-CO2 emissions from human-influenced tropical peatlands particularly scarce. The aim of this study was to quantify soil CH4 and N2O fluxes from smallholder agricultural systems on tropical peatlands in Southeast Asia and assess their environmental controls. The study was carried out in four regions in Malaysia and Indonesia. CH4 and N2O fluxes and environmental parameters were measured in cropland, oil palm plantation, tree plantation, and forest. Annual CH4 emissions (in kg CH4 ha-1 year-1) were: 70.7 ± 29.5, 2.1 ± 1.2, 2.1 ± 0.6 and 6.2 ± 1.9 at the forest, tree plantation, oil palm and cropland land-use classes, respectively. Annual N2O emissions (in kg N2O ha-1 year-1) were: 6.5 ±2.8, 3.2 ± 1.2, 21.9 ± 11.4 and 33.6 ± 7.3 in the same order as above, respectively. Annual CH4 emissions were strongly determined by water table depth (WTD) and increased exponentially when annual WTD was above –25 cm. In contrast, annual N2O emissions were strongly correlated with mean total dissolved nitrogen (TDN) in soil water, following a sigmoidal relationship, up to an apparent threshold of 10 mg N L-1 beyond which TDN seemingly ceased to be limiting for N2O production. The new emissions data for CH4 and N2O presented here should help to develop more robust country level ‘emission factors’ for the quantification of national GHG inventory reporting. The impact of TDN on N2O emissions suggests that soil nutrient status strongly impact emissions, and therefore, policies which reduce N-fertilisation inputs might contribute to emissions mitigation from agricultural peat landscapes. However, the most important policy intervention for reducing emissions is one that reduces the conversion of peat swamp forest to agriculture in peatlands in the first place