Abstract. Syahrinudin, Hartati W, Sudarmadji T, Krisdianto N, Ibrahim. 2019. Biochar enriched with organic fertilizer improves the survival and growth rate of Anthocepalus cadamba seedlings planted on degraded spodosols. Biodiversitas 20: 3741-3750. The application of biochar for the improvement of soil properties and fertility has drawn enormous interest worldwide nowadays and numerous application options are now available. This research was aimed to evaluate the effects of the application of biochar and organic fertilizers on the survival and growth of Anthocepalus cadamba seedlings planted on degraded spodosols soil on bioassay trial in the nursery. Bioassay trial was carried out in the nursery of Faculty of Forestry, Mulawarman University, Samarinda, Indonesia, employing a 2-factors Completely Randomized Design (CRD) with factor 1 was the rate of biochar application (i.e. six levels of treatment: 0 (control), 2, 5, 10, 25 and 100%v of biochar), and factor 2 (enrichment of organic fertilizers, i.e. with enrichment and without enrichment), and each treatment combination had 3 replications. The results showed that biochar application alone improved height and diameter growth rate of A. cadamba seedlings by 253% and 116% of control treatment (without biochar), respectively. Enrichment of organic fertilizers gave further improvement in height and diameter growth rate of A. cadamba seedlings to 386% and 150% of control treatment (without biochar), respectively. Furthermore, biochar application improved survival and biomass growth rate of the seedlings. Enrichment of organic fertilizers into biochar improved not only seedling growth rate but also more interestingly the carrying capacity of spodosols to biochar application rate. We concluded that biochar application complemented with enrichment of organic fertilizers on spodosols is highly promising for the improvement of both soil carbon sequestration and plant growth performance.

Saidy AR, Mariana ZT, Adji FA, Nusantara RW, Fitria I, Syahrinudin. 2018. Carbon mineralization dynamics of tropicalpeats in relation to peat characteristics. Biodiversitas 19: 1413-1421. Understanding the dynamics of carbon mineralization of peats inthe tropical areas is of essential significance in controlling carbon dioxide (CO2) gas emission rates. An incubation study of tropicalpeats sampled from 3 different sites of the Barito Basin on the Borneo Island, Indonesia (uncultivated, used for paddy cultivation for  5years and 5-10 years) was carried out to investigate a relationship between CO2 production and peat characteristics. Results of studyrevealed that land use change from uncultivated peats to paddy fields resulted in significant changes in the chemical structure of peatorganic carbon. Carbohydrate contents of the peat decreased significantly as a consequence of the conversion of natural peats to paddyfields. However, the paddy peats contained higher lignin than uncultivated peats. Changes in the chemical structure of the tropical peatsresulted in changes in carbon mineralization. Carbon mineralization of uncultivated peats ranged from 29255310 mg CO2-C kg-1 peat,while carbon mineralization of 10652678 mg CO2-C kg-1 C peat was observed for paddy peats. Moreover, carbon mineralization dataobtained from the experiment fitted properly to a two-pool C mineralization model. The developed carbon mineralization model showedthat slowly and rapidly decomposable pools have a close relation with rubbed fiber and carbohydrate content data. Thus, results of thisstudy suggested that carbon mineralization of peats could be estimated appropriately using rubbed fiber and carbohydrate content data.

Gumiri S, Ardianor, Syahrinudin, Anshari GZ, Komai Y, Taki K, Tachibana H. 2018. Seasonal yield and composition of aninland artisanal fishery in a humic floodplain ecosystem of Central Kalimantan, Indonesia. Biodiversitas 19: 1181-1185. Seasonal yieldof an inland artisanal fishery was studied in 2015 in the Takapan Floodplain Lake located along the Rungan River of Central KalimantanProvince-Indonesia. Record on daily fish catch consisting weight data and species composition was made in situ along with a one-yearrainfall data that was collected from the nearest Meteorological Station located in Palangka Raya City airport. Results showed thatthroughout the year, total annual yield of captured fishes reached 4.8 tons comprised of 34 commercial freshwater fish species. Seasonalyield varied considerably in which fish capture was higher during the rainy season than on the dry season. The transition period fromrainy to dry season was found to be the peak period of fish capture in the floodplain. Of the 34 fish species, the most abundant specieswas Channa striata that accounted to almost 50% of total annual fish yield. The two most abundant fishes, Channa striata, andKryptopterus palembangensis were a top predatory blackfish and an omnivorous surface water whitefish, respectively. This resultindicated that the studied floodplain habitat was still in good condition, however, conservation is needed to maintain the sustainability offreshwater fish resource in the future.

Abstract. Syahrinudin, Denich M, Becker M, Hartati W, Vleg PLG. 2020. Biomass and carbon distribution on Imperata cylindrica grasslands. Biodiversitas 21: 74-79. Invasive plants can alter the diversity and composition of ecological communities leading to ecosystem change both function and biodiversity issues. Imperata cylindrica is an invasive grass thrives on wide range of soil fertility and climatic condition forming a vast grassland area of this species. Conversion of such lands into agriculture and plantation is costly and high capital demanding. This work was devoted to investigate CO2 mitigation potential of the conversion I. cylindrica grassland to plantations in Sumatra and East Kalimantan, Indonesia. Stratified sampling technique was applied for the determination of biomass and carbon stock of the system studied. Results show that I. cylindrica grassland stored only a relatively small amount of biomass C (5.9-7.6 mg ha-1) implying that conversion into a more C-rich tree-based system would be promising tool to enhance C sequestration. Soil C content at both study sites decreased significantly with depth from the top 15 cm to the 3-m depth and was considerably higher in East Kalimantan than in Sumatra. Provided similar land-use history, the differences in soil C are likely to be related to the level prior to the invasion. Roots of I. cylindrica extended to a maximum depth of only 180 cm, but most of these roots being confined to the topsoil, little organic material is deposited in deeper layers. Despite the dense mat of rhizomes, the extent of C stored in the topsoils was modest. As sequestration is of global concern, the conversion of this grassland into systems with higher biomass accumulation and deeper root penetration is required.

Interests on biochar application for the improvement of soil properties and fertily are increasing worldwide nowadays and numerous of production techniques are now available. This research was aimed at the investigation (a) on the characteristics biochar produced by 3 (three) different techniques, i.e: (1) traditional soil pit, (2) retort closed drum and (3) open drum kilns, as well as (b) on growth (height, leaf number and survival) response of Shorea leprosula seedling to 20%v biochar application on bioassay trial in the nursery. Bioassay trial was carried out in nursery of Forestry Faculty of Mulawarman University, Samarinda, Indonesia and was in accordance with Completely Randomized Design (CRD) applying 4 treatments and 3 replications.Of those 3 production techniques, retort closed drum kiln production technique was the most promising for further development and adoption providing not only that the biochar produced gave better properties and soil improvement capacity but also higher production recovery and less time and labour involvement. Furthermore, eventhough it was not statistically significant, biochar produced by retort closed drum gave better growth (height and leaf number) rate to S. leprosula seedlings in bioassay trial compared to those given by biochar produced by other techniques and without biochar treatments.

Interests on biochar application for the improvement of soil properties and fertily are increasing worldwide nowadays and numerous of production techniques are now available. This research was aimed at the investigation (a) on the characteristics biochar produced by 3 (three) different techniques, i.e: (1) traditional soil pit, (2) retort closed drum and (3) open drum kilns, as well as (b) on growth (height, leaf number and survival) response of Shorea leprosula seedling to 20%v biochar application on bioassay trial in the nursery. Bioassay trial was carried out in nursery of Forestry Faculty of Mulawarman University, Samarinda, Indonesia and was in accordance with Completely Randomized Design (CRD) applying 4 treatments and 3 replications.Of those 3 production techniques, retort closed drum kiln production technique was the most promising for further development and adoption providing not only that the biochar produced gave better properties and soil improvement capacity but also higher production recovery and less time and labour involvement. Furthermore, eventhough it was not statistically significant, biochar produced by retort closed drum gave better growth (height and leaf number) rate to S. leprosula seedlings in bioassay trial compared to those given by biochar produced by other techniques and without biochar treatments.

Mangrove forests serve as a buffer against sedimentation from the mainland into the sea, protect the area from coastal erosion, and prevent seawater intrusion in some ecological types of coastal environments. Additionally, because soil and below-ground biomass retain a significant quantity of carbon, they are essential for carbon sequestration. The current study seeks to estimate the soil organic carbon stock of mangroves associated with natural regeneration, mangrove rehabilitation areas and abandoned shrimp ponds, in Mahakam Delta, East Kalimantan, Indonesia. A 125-meter-long transect line was used to collect data, with three sampling points representing the length of the transect line. Each soil sample was taken at three different depths: 0-50 cm, 50-100 cm, and 100-150 cm. After that, the samples were taken to the laboratory for carbon analysis. The mangrove rehabilitation area had the highest bulk density at 8.64 gr/cm3, followed by natural mangroves along the river border at 7.67 gr/cm3, and abandoned ponds had the lowest at 7.16 gr/cm3. The rehabilitation area had the highest soil carbon stock at 1120 tons/ha, followed by natural mangroves along the riverside at 686 tons/ha and abandoned ponds at 383 tons/ha. In accordance with the study, mangrove rehabilitation regions had larger soil carbon stocks than natural regeneration along the riverside and abandoned ponds. In order to protect the ecologically significant mangrove ecosystem and minimize the effects of climate change, mangrove restoration and rehabilitation are necessary.

Eucalyptus pellita F. Muell is one of the species developed in industrial forest plantations that has the potential for pulp and paper. Therefore, this research aims to determine the concentration of N, P, and K nutrients in the Eucalyptus pellita F. Muell tree components. This research was conducted on two locations in plantation in East Kalimantan, Indonesia, which included 1, 3, and 5-year-old plants on Ultisols soil and 13-year-old plants on Spdosols soil. There were 3 plots made in a circular form with an area of 0.05 ha for each plant age for the tree inventory. Furthermore, the census of inventory tree diameters was conducted and 24 representatives were harvested to determine nutrient concentrations for each tree component at a specific age. The method used for the analysis of N, P, and K nutrients were the Kjeldahl, Spectrophotometer, and Flamephotometer, respectively. The results showed that: 1) at the age of 1 year, the highest and lowest concentrations of N were in leaf (11.03 mg/g) and stem wood (5.57 mg/g), while P was showed in branch+twig bark (0.30 mg/g) and branch+twig wood (0.17mg/g), and K was in branch+twig bark (14.05 mg/g) and branch+twig wood (3.56 mg/g). 2) At the plat age of 3 years, the highest and lowest concentrations of N were in leaf (13.63 mg/g) and stem wood (3.21 mg/g), while P was in leaf (0.40 mg/g) and stem wood (0.17 mg/g) and K was in leaf (12.12 mg/g) and stem wood (2.07 mg/g). 3) At the plant age of 5 years, the highest and lowest concentrations of N were in leaf (12.92 mg/g) and branch+twig wood (4.92 mg/g), while P were in branch+twig bark (8.65 mg/g) and branch+twig wood (3.15 mg/g), and K was showed in leaf (6.66 mg/g) and stem wood (2.38 mg/g). 4) At the plant age of 13 years, the highest and lowest concentrations of N was in leaf (13.13 mg/g) and branch+twig wood (4.90 mg/g), while P were in stem bark (1.27 mg/g) and stem wood (0.50 mg/g), and K were in leaf (9.83 mg/g) and stem wood (2.33 mg/g). These differences in nutrient concentrations of Eucalyptus pellita F.muell components are influenced by species, age, and soil type factors.