NobleBlocks

Tadulako University

UniversityPalu, Indonesia

Research output, citation impact, and the most-cited recent papers from Tadulako University (Indonesia). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
15.9K
Citations
80.2K
h-index
72
i10-index
1.7K
Also known as
Tadulako UniversityUniversitas Tadulako

Top-cited papers from Tadulako University

Trade-offs between multifunctionality and profit in tropical smallholder landscapes
Ingo Graß, Christoph Kubitza, Vijesh V. Krishna, Marife D. Corre +4 more
2020· Nature Communications775doi:10.1038/s41467-020-15013-5

Land-use transitions can enhance the livelihoods of smallholder farmers but potential economic-ecological trade-offs remain poorly understood. Here, we present an interdisciplinary study of the environmental, social and economic consequences of land-use transitions in a tropical smallholder landscape on Sumatra, Indonesia. We find widespread biodiversity-profit trade-offs resulting from land-use transitions from forest and agroforestry systems to rubber and oil palm monocultures, for 26,894 aboveground and belowground species and whole-ecosystem multidiversity. Despite variation between ecosystem functions, profit gains come at the expense of ecosystem multifunctionality, indicating far-reaching ecosystem deterioration. We identify landscape compositions that can mitigate trade-offs under optimal land-use allocation but also show that intensive monocultures always lead to higher profits. These findings suggest that, to reduce losses in biodiversity and ecosystem functioning, changes in economic incentive structures through well-designed policies are urgently needed.

Tradeoffs between income, biodiversity, and ecosystem functioning during tropical rainforest conversion and agroforestry intensification
Ingolf Steffan‐Dewenter, Michael Kessler, Jan Barkmann, Merijn M. Bos +4 more
2007· Proceedings of the National Academy of Sciences526doi:10.1073/pnas.0608409104

Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by approximately 75% and species richness of forest-using species by approximately 60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by approximately 40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends.

BIODIVERSITY INDICATOR GROUPS OF TROPICAL LAND‐USE SYSTEMS: COMPARING PLANTS, BIRDS, AND INSECTS
Christian Schulze, Matthias Waltert, P. Kessler, Ramadhanil Pitopang +4 more
2004· Ecological Applications487doi:10.1890/02-5409

Tropical landscapes are dominated by land‐use systems, but their contribution to the conservation of biodiversity is largely unknown. Since changes in biodiversity in response to human impact are known to differ widely among taxonomic groups and guilds, there is a need for multidisciplinary collaboration of plant, vertebrate, and invertebrate experts. We used inventories of trees, understory plants, birds (subdivided into endemics, insectivores, frugivores/nectar feeders), butterflies (endemics, fruit feeders), and dung beetles in Sulawesi (Indonesia) to characterize a gradient from near‐primary to secondary forests, agroforestry systems, and annual crops. As expected, overall species richness tended to decrease within this gradient of increasing habitat modification, but, in contrast to previous studies, we found the species richness between most taxonomic groups to be significantly correlated (36 out of 38 pairwise comparisons). However, on average only 48% of the variance could be explained (within the five main groups), and only a few taxonomic groups/guilds turned out to be good predictors for others: for example, trees for fruit‐ and nectar‐feeding birds (88% explanation) and fruit‐feeding butterflies (83%), endemic birds for endemic butterflies (72%), and frugivorous/nectar‐feeding birds for fruit‐feeding butterflies (67%). Although biodiversity of land‐use systems showed taxonomic group‐ and guild‐specific differences, most groups were affected in a similar way by habitat modification. Near‐primary forest sites proved to be of principal importance for conservation; however, land‐use systems such as secondary forests (for understory plants, birds, and butterflies) and agroforestry systems (for butterflies) supported relatively high numbers of species and might play a significant role for biodiversity conservation in tropical landscapes.

Combining high biodiversity with high yields in tropical agroforests
Yann Clough, Jan Barkmann, Jana Juhrbandt, Michael Kessler +4 more
2011· Proceedings of the National Academy of Sciences484doi:10.1073/pnas.1016799108

Local and landscape-scale agricultural intensification is a major driver of global biodiversity loss. Controversially discussed solutions include wildlife-friendly farming or combining high-intensity farming with land-sparing for nature. Here, we integrate biodiversity and crop productivity data for smallholder cacao in Indonesia to exemplify for tropical agroforests that there is little relationship between yield and biodiversity under current management, opening substantial opportunities for wildlife-friendly management. Species richness of trees, fungi, invertebrates, and vertebrates did not decrease with yield. Moderate shade, adequate labor, and input level can be combined with a complex habitat structure to provide high biodiversity as well as high yields. Although livelihood impacts are held up as a major obstacle for wildlife-friendly farming in the tropics, our results suggest that in some situations, agroforests can be designed to optimize both biodiversity and crop production benefits without adding pressure to convert natural habitat to farmland.

Ecological and socio-economic functions across tropical land use systems after rainforest conversion
Jochen Drescher, Katja Rembold, Kara Allen, Philip Beckschäfer +4 more
2016· Philosophical Transactions of the Royal Society B Biological Sciences394doi:10.1098/rstb.2015.0275

Tropical lowland rainforests are increasingly threatened by the expansion of agriculture and the extraction of natural resources. In Jambi Province, Indonesia, the interdisciplinary EFForTS project focuses on the ecological and socio-economic dimensions of rainforest conversion to jungle rubber agroforests and monoculture plantations of rubber and oil palm. Our data confirm that rainforest transformation and land use intensification lead to substantial losses in biodiversity and related ecosystem functions, such as decreased above- and below-ground carbon stocks. Owing to rapid step-wise transformation from forests to agroforests to monoculture plantations and renewal of each plantation type every few decades, the converted land use systems are continuously dynamic, thus hampering the adaptation of animal and plant communities. On the other hand, agricultural rainforest transformation systems provide increased income and access to education, especially for migrant smallholders. Jungle rubber and rubber monocultures are associated with higher financial land productivity but lower financial labour productivity compared to oil palm, which influences crop choice: smallholders that are labour-scarce would prefer oil palm while land-scarce smallholders would prefer rubber. Collecting long-term data in an interdisciplinary context enables us to provide decision-makers and stakeholders with scientific insights to facilitate the reconciliation between economic interests and ecological sustainability in tropical agricultural landscapes.

Psychological Impacts of Students on Online Learning During the Pandemic COVID-19
Andi Wahyu Irawan, Dwisona Dwisona, Mardi Lestari
2020· KONSELI Jurnal Bimbingan dan Konseling (E-Journal)354doi:10.24042/kons.v7i1.6389

The Indonesian government formally enforces rules of study, worship, and work from home from March 16, 2020. Minimizing and limiting meetings involving physical contact is an effort to reduce the spread of the COVID-19 virus. These conditions have implications for the effectiveness of the learning process in higher education. The purpose of this study was to identify the impact of student psychology on online learning during the COVID-19 pandemic. The research method uses a qualitative research type of phenomenology. The research subjects were 30 students of Mulawarman University who were interviewed via telephone. The research findings show that (1) students have started to get bored with online learning after the first two weeks of learning from home, (2) considerable anxiety on research subjects whose parents have low income, because they have to buy quotas to be able to participate in online learning, ( 3) mood or mood changes occur due to too many assignments and are considered ineffective by students. Suggestions and recommendations from this research are the need for severe efforts in assisting the psychological well-being of students through the involvement of counselors and psychologists.

Land-use choices follow profitability at the expense of ecological functions in Indonesian smallholder landscapes
Yann Clough, Vijesh V. Krishna, Marife D. Corre, Kevin Darras +4 more
2016· Nature Communications294doi:10.1038/ncomms13137

Smallholder-dominated agricultural mosaic landscapes are highlighted as model production systems that deliver both economic and ecological goods in tropical agricultural landscapes, but trade-offs underlying current land-use dynamics are poorly known. Here, using the most comprehensive quantification of land-use change and associated bundles of ecosystem functions, services and economic benefits to date, we show that Indonesian smallholders predominantly choose farm portfolios with high economic productivity but low ecological value. The more profitable oil palm and rubber monocultures replace forests and agroforests critical for maintaining above- and below-ground ecological functions and the diversity of most taxa. Between the monocultures, the higher economic performance of oil palm over rubber comes with the reliance on fertilizer inputs and with increased nutrient leaching losses. Strategies to achieve an ecological-economic balance and a sustainable management of tropical smallholder landscapes must be prioritized to avoid further environmental degradation.

E-LEARNING SEBAGAI MEDIA PEMBELAJARAN INTERAKTIFBERBASIS TEKNOLOGI INFORMASI
Mohammad Yazdi
2012250

The development of science and technology, especially information technology, internet use in education continues to grow. Use of the Internet is not just for distance education, but also developed in the conventional education system. E-learning is a learning model that is created in digital format through an electronic device. Purpose of the use of e-learning in the learning system is to expand access to education public, so that learning modules can be accessed easily, without diabatasi space and time, interactive, and effective. In this paper a prototype using a software development methodology that emphasizes the approach to aspects of design, functionality and user-interface. The final product is expected to be a module-based learning application of information technology. Key words: Internet, the quality of education, information technology, e-learning

Soil Nitrogen-Cycling Responses to Conversion of Lowland Forests to Oil Palm and Rubber Plantations in Sumatra, Indonesia
Kara Allen, Marife D. Corre, Aiyen Tjoa, Edzo Veldkamp
2015· PLoS ONE243doi:10.1371/journal.pone.0133325

Rapid deforestation in Sumatra, Indonesia is presently occurring due to the expansion of palm oil and rubber production, fueled by an increasing global demand. Our study aimed to assess changes in soil-N cycling rates with conversion of forest to oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) plantations. In Jambi Province, Sumatra, Indonesia, we selected two soil landscapes - loam and clay Acrisol soils - each with four land-use types: lowland forest and forest with regenerating rubber (hereafter, "jungle rubber") as reference land uses, and rubber and oil palm as converted land uses. Gross soil-N cycling rates were measured using the 15N pool dilution technique with in-situ incubation of soil cores. In the loam Acrisol soil, where fertility was low, microbial biomass, gross N mineralization and NH4+ immobilization were also low and no significant changes were detected with land-use conversion. The clay Acrisol soil which had higher initial fertility based on the reference land uses (i.e. higher pH, organic C, total N, effective cation exchange capacity (ECEC) and base saturation) (P≤0.05-0.09) had larger microbial biomass and NH4+ transformation rates (P≤0.05) compared to the loam Acrisol soil. Conversion of forest and jungle rubber to rubber and oil palm in the clay Acrisol soil decreased soil fertility which, in turn, reduced microbial biomass and consequently decreased NH4+ transformation rates (P≤0.05-0.09). This was further attested by the correlation of gross N mineralization and microbial biomass N with ECEC, organic C, total N (R=0.51-0. 76; P≤0.05) and C:N ratio (R=-0.71 - -0.75, P≤0.05). Our findings suggest that the larger the initial soil fertility and N availability, the larger the reductions upon land-use conversion. Because soil N availability was dependent on microbial biomass, management practices in converted oil palm and rubber plantations should focus on enriching microbial biomass.

Long-term carbon sink in Borneo’s forests halted by drought and vulnerable to edge effects
Lan Qie, Simon L. Lewis, Martin J. P. Sullivan, Gabriela López‐González +4 more
2017· Nature Communications173doi:10.1038/s41467-017-01997-0

Abstract Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha −1 per year (95% CI 0.14–0.72, mean period 1988–2010) in above-ground live biomass carbon. These results closely match those from African and Amazonian plot networks, suggesting that the world’s remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997–1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.

The Effect of Temperature and Duration of Curing on the Strength of Fly Ash Based Geopolymer Mortar
Andi Arham Adam, X.X.X. Horianto
2014· Procedia Engineering173doi:10.1016/j.proeng.2014.12.199

The optimum temperature and duration of curing is essential in geopolymerization reaction to achieve higher strength. As such, fly ash based geopolymer mortars were prepared by varying the curing temperature of 80, 100 and 120 °C, for the duration of 4, 6 and 20 hours. The fly ash was activated by sodium silicate and sodium hydroxide solution. The dosage of activator was 55% and the ratio between sodium silicate and alkaline activator was 1: 2. The results show that the highest compressive strength was obtained at the temperature and duration of curing of 120 °C and 20 hours.

Palm kernel meal in broiler diets: effect on chicken performance and health
B. Sundu, Arun Kumar, J. G. Dingle
2006· World s Poultry Science Journal164doi:10.1079/wps2005100

An increase in the production of palm kernel meal (PKM) coupled with the concern for continued availability of conventional feedstuffs in some parts of the world has led to research to establish the maximum inclusion level of palm kernel meal in broiler diets. The results suggested that palm kernel meal has no anti-nutritional properties and thus its inclusion is safe up to at least 40% in the diet, provided the diet is balanced in amino acids and metabolisable energy. Although feed digestibility is decreased due to high dietary fibre when PKM is included in the diet, the feed intake is increased. This makes total digestible nutrient intake relatively high. β-mannan is the main component of palm kernel meal non-starch polysaccharide (NSP). Both mannose and manno-oligosaccharides have been reported to act as prebiotics. The inclusion of palm kernel meal in the diet improves the immune system of birds and reduces pathogenic bacteria and increases the population of non-pathogenic bacteria in the intestine. These two benefits should be considered as strong recommendations for using palm kernel meal in broiler diets, particularly in palm kernel meal producing countries, not only for increasing bird productivity but also to improve chicken health. Selective enzyme addition increases feed efficiency and digestibility as well as decreasing the moisture content of faeces.

Alpha and beta diversity of plants and animals along a tropical land‐use gradient
Michael Kessler, Stefan Abrahamczyk, Merijn M. Bos, Damayanti Buchori +4 more
2009· Ecological Applications160doi:10.1890/08-1074.1

Assessing the overall biological diversity of tropical rain forests is a seemingly insurmountable task for ecologists. Therefore, researchers frequently sample selected taxa that they believe reflect general biodiversity patterns. Usually, these studies focus on the congruence of alpha diversity (the number of species found per sampling unit) between taxa rather than on beta diversity (turnover of species assemblages between sampling units). Such approaches ignore the potential role of habitat heterogeneity that, depending on the taxonomic group considered, can greatly enhance beta diversity at local and landscape scales. We compared alpha and beta diversity of four plant groups (trees, lianas, terrestrial herbs, epiphytic liverworts) and eight animal groups (birds, butterflies, lower canopy ants, lower canopy beetles, dung beetles, bees, wasps, and the parasitoids of the latter two) at 15 sites in Sulawesi, Indonesia, that represented natural rain forest and three types of cacao agroforests differing in management intensity. In total, we recorded 863 species. Patterns of species richness per study site varied strongly between taxonomic groups. Only 13-17% of the variance in species richness of one taxonomic group could be predicted from the species richness of another, and on average 12-18% of the variance of beta diversity of a given group was predicted by that in other groups, although some taxon pairs had higher values (up to 76% for wasps and their parasitoids). The degree of congruence of patterns of alpha diversity was not influenced by sampling completeness, whereas the indicator value for beta diversity improved when using a similarity index that accounts for incomplete sampling. The indication potential of alpha diversity for beta diversity and vice versa was limited within taxa (7-20%) and virtually nil between them (0-4%). We conclude that different taxa can have largely independent patterns of alpha diversity and that patterns of beta diversity can be more congruent. Thus, conservation plans on a landscape scale need to put more emphasis on the high heterogeneity of agroforests and the overarching role of beta diversity shaping overall diversity patterns.

Forest aboveground biomass along an elevational transect in Sulawesi, Indonesia, and the role of Fagaceae in tropical montane rain forests
Heike Culmsee, Christoph Leuschner, Gerald M. Moser, Ramadhanil Pitopang
2010· Journal of Biogeography156doi:10.1111/j.1365-2699.2009.02269.x

Abstract Aim This study investigates how estimated tree aboveground biomass (AGB) of tropical montane rain forests varies with elevation, and how this variation is related to elevational change in floristic composition, phylogenetic community structure and the biogeography of the dominant tree taxa. Location Lore Lindu National Park, Sulawesi, Indonesia. Methods Floristic inventories and stand structural analyses were conducted on 13 plots (each 0.24 ha) in four old‐growth forest stands at 1050, 1400, 1800 and 2400 m a.s.l. (submontane to upper montane elevations). Tree AGB estimates were based on d.b.h., height and wood specific gravity. Phylogenetic diversity and biogeographical patterns were analysed based on tree family composition weighted by AGB. Elevational trends in AGB were compared with other Southeast Asian and Neotropical transect studies ( n = 7). Results AGB was invariant from sub‐ to mid‐montane elevation (309–301 Mg ha −1 ) and increased slightly to 323 Mg ha −1 at upper montane elevation. While tree and canopy height decreased, wood specific gravity increased. Magnoliids accounted for most of the AGB at submontane elevations, while eurosids I (including Fagaceae) contributed substantially to AGB at all elevations. Phylogenetic diversity was highest at upper montane elevations, with co‐dominance of tree ferns, Podocarpaceae, Trimeniaceae and asterids/euasterids II, and was lowest at lower/mid‐montane elevations, where Fagaceae contributed > 50% of AGB. Biogeographical patterns showed a progression from dominant tropical families at submontane to tropical Fagaceae ( Castanopsis , Lithocarpus ) at lower/mid‐montane, and to conifers and Australasian endemics at upper montane elevations. Cross‐continental comparisons revealed an elevational AGB decrease in transects with low/no presence of Fagaceae, but relatively high AGB in montane forests with moderate to high abundance of this family. Main conclusions AGB is determined by both changes in forest structure and shifts in species composition. In our study, these two factors traded off so that there was no net change in AGB, even though there were large changes in forest structure and composition along the elevational gradient. Southeast Asian montane rain forests dominated by Fagaceae constitute important carbon stocks. The importance of biogeography and species traits for biomass estimation should be considered by initiatives to reduce emissions from deforestation and forest degradation (REDD) and in taxon choice in reforestation for carbon offsetting.

Effects of an experimental drought on the functioning of a cacao agroforestry system, Sulawesi, Indonesia
Luitgard Schwendenmann, Edzo Veldkamp, Gerald M. Moser, Dirk Hölscher +4 more
2009· Global Change Biology152doi:10.1111/j.1365-2486.2009.02034.x

Abstract Agroforestry systems may play a critical role in reducing the vulnerability of farmers' livelihood to droughts as tree‐based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/ Gliricidia stand over a 13‐month period. Soil water content was successfully reduced down to a soil depth of at least 2.5 m. Contrary to our expectations we measured only relatively small nonsignificant changes in cacao (−11%) and Gliricidia (−12%) sap flux densities, cacao leaf litterfall (+8%), Gliricidia leaf litterfall (−2%), soil carbon dioxide efflux (−14%), and cacao yield (−10%) during roof closure. However, cacao bean yield in roof plots was substantially lower (−45%) compared with control plots during the main harvest following the period when soil water content was lowest. This indicates that cacao bean yield was more sensitive to drought than other ecosystem functions. We found evidence in this agroforest that there is complementary use of soil water resources through vertical partitioning of water uptake between cacao and Gliricidia . This, in combination with acclimation may have helped cacao trees to cope with the induced drought. Cacao agroforests may thus play an important role as a drought‐tolerant land use in those (sub‐) tropical regions where the frequency and severity of droughts is projected to increase.

Potensi Pembelajaran Pendidikan Jasmani Olahraga Dan Kesehatan (PJOK) Di Tengah Pandemi Corona Virus Disease (COVID)-19 Di Sekolah Dasar
Herlina Herlina, Maman Suherman
2020150

Serangan Corona Virus Disease (covid)-19 membawa dampak yang signifikan pada semua sendi kehidupan manusia. Pendidikan khususnya pendidikan formal adalah salah satu komponen kehidupan manusia yang terdampak oleh serangan virus tersebut. Pembelajaran yang selama ini dilaksanakan dengan tatap muka, secara tiba-tiba harus dilakukan secara daring. Selain kendala terhadap akses internet, sejumlah mata pelajaran  yang  berbasis praktik seperti  IPA dan mata pelajaran berbasis aktivitas fisik seperti PJOK juga mengalami kesulitan dalam pembelajaran daring. Berdasarkan penelitian yang dilakukan pada subject terbatas di SDN Sumari, artikel ini mengkaji potensi pembelajaran PJOK di masa pandemi covid-19. Menggunakan metode penelitian kualitatif, melalui teknik pengumpulan data yakni wawancara, pengamatan dan penelusuran pustaka daring dengan analisis data kualitatif deskriptif. Hasil penelitian menunjukkan bahwa pembelajaran PJOK memiliki potensi untuk dikembangkan di tengah masa pandemi covid-19 melalui model pembelajaran jarak jauh dengan pendekatan kolaboratif.

Intensive tropical land use massively shifts soil fungal communities
Nicole Brinkmann, Dominik Schneider, Josephine Sahner, Johannes Ballauff +4 more
2019· Scientific Reports141doi:10.1038/s41598-019-39829-4

Soil fungi are key players in nutrient cycles as decomposers, mutualists and pathogens, but the impact of tropical rain forest transformation into rubber or oil palm plantations on fungal community structures and their ecological functions are unknown. We hypothesized that increasing land use intensity and habitat loss due to the replacement of the hyperdiverse forest flora by nonendemic cash crops drives a drastic loss of diversity of soil fungal taxa and impairs the ecological soil functions. Unexpectedly, rain forest conversion was not associated with strong diversity loss but with massive shifts in soil fungal community composition. Fungal communities clustered according to land use system and loss of plant species. Network analysis revealed characteristic fungal genera significantly associated with different land use systems. Shifts in soil fungal community structure were particularly distinct among different trophic groups, with substantial decreases in symbiotrophic fungi and increases in saprotrophic and pathotrophic fungi in oil palm and rubber plantations in comparison with rain forests. In conclusion, conversion of rain forests and current land use systems restructure soil fungal communities towards enhanced pathogen pressure and, thus, threaten ecosystem health functions.

Reducing Fertilizer and Avoiding Herbicides in Oil Palm Plantations—Ecological and Economic Valuations
Kevin Darras, Marife D. Corre, Greta Formaglio, Aiyen Tjoa +4 more
2019· Frontiers in Forests and Global Change138doi:10.3389/ffgc.2019.00065

Oil palm plantations are intensively managed agricultural systems that increasingly dominate certain tropical regions. Oil palm monocultures have been criticized because of their reduced biodiversity compared to the forests they historically replaced, and because of their negative impact on soils, water, and climate. We experimentally test whether less intensive management schemes may enhance biodiversity and lessen detrimental effects on the environment while maintaining high yields. We compare reduced versus conventional fertilization, as well as mechanical versus chemical weed control (with herbicides) in a long-term, full-factorial, multidisciplinary experiment. We conducted the experiment in an oil palm company estate in Sumatra, Indonesia, and report the results of the first two years. We measured soil nutrients and functions, surveyed above- and below-ground organisms, tracked oil palm condition and productivity, and calculated plantation gross margins. Plants, aboveground arthropods and belowground animals were positively affected by mechanical versus chemical weed control, but we could not detect effects on birds and bats. There were no detectable negative effects of reduced fertilization or mechanical weeding on oil palm yields, fine roots, or leaf area index; however, stem growth was enhanced under mechanical weeding. Also, we could not detect detrimental effects of the reduced fertilization and mechanical weeding on soil nutrients and functions (mineral nitrogen, bulk density, and litter decomposition), but water infiltration and base saturation tended to be higher under mechanical weeding, while soil moisture and microbial biomass varied with treatment. Economic performance, measured as gross margins, was higher under reduced fertilization. There might be a delayed response of oil palm to the different management schemes applied, so results of future years may confirm whether this is a sustainable management strategy. Nevertheless, the initial effects of the experiment are encouraging to consider less intensive management practices as economically and ecologically viable options for oil palm plantations.

Uji Kualitatif Senyawa Metabolit Sekunder Pada Daun Palado (Agave Angustifolia) Yang Diekstraksi Dengan Pelarut Air Dan Etanol
Ergina Ergina, Siti Nuryanti, Indarini Dwi Pursitasari
2017124

Study on qualitative test of secondary metabolites compounds has been done on Palado leaves (Agave angustifolia) extracted in water and ethanol by maceration technique. The aim of this research was to determine the chemical content of Palado leaves. The methode used was phytochemical scrinning (qualitative test) using test tube to determine type of the active compounds contained in the plant. Chemicals tested in this study were alkaloids, terpenoids, steroids, flavonoids, and tannins. Components of Palado leaves extracted in water and ethanol were analysed by colour test using several reagents to determine alkaloids, terpenoids, steroids, flavonoids, and tannins. Specific reagents used in this study interacted with the sample based on the principle of ‘like dissolve like’. The results showed that the water and ethanol extracts of Palado leaves contained alcaloids, flavonoids dan tannins.

Optical Properties of Silver Nanoparticles for Surface Plasmon Resonance (SPR)-Based Biosensor Applications
Lufsyi Mahmudin, Edi Suharyadi, Agung Bambang Setio Utomo, Kamsul Abraha
2015· Journal of Modern Physics123doi:10.4236/jmp.2015.68111

It has been successfully carried out the synthesis of silver nanoparticles by chemical reduction method. Silver nitrate (AgNO3) is used as the metal precursor and trisodium citrate as the reducing agent as well as the use of polyvinyl alcohol (PVA) as a stabilizer. The formation of silver nanoparticles was observed visually with discoloration (yellow). To excite surface plasmons, attenuated total reflection (ATR) method is used with Krestchmann configuration of the prism coupling. The maximum absorption band in the UV-Vis spectrometer shows a red shift of 429.43 nm wavelength for a colloidal solution of silver nanoparticles without PVA and 429.01 nm with PVA. The addition of PVA sharpened absorption spectrum curve and produce a broad absorption band which is indicative of a smaller particle size. TEM images showed that the morphology (crystallites) silver nanoparticles have nearly spherical geometry with dispersive particle distribution. Dispersibility of nanoparticles such as this could potentially be used as an active ingredient of SPR biosensor. The observation of the SPR phenomenon shows the SPR angle shift of 0.1° when a thin layer of silver as an active ingredient a biosensor coated with silver nanoparticles and 0.2° when silver nanoparticles with PVA. SPR angle shift and increase the reflectance values caused by changes in surface Plasmon, which can be a reference that the SPR phenomenon with the sensing surface modification using an additional layer of silver nanoparticles can increase sensitivity.