1,720,965 research outputs found
Designing a Decision-Support Tool for Fertilizer Recommendations in Oil Palm Smallholders
Full text linkOil palm (Elaeis guineensis Jacq.), originally from West Africa, now accounts for 42% of global vegetable oil production and mainly includes key regions cultivated in tropical regions of Southeast Asia, West Africa, South America, and Central America. Despite its economic significance, the oil palm industry faces challenges of stagnant yields and large yield gaps, particularly among independent smallholders. These issues often stem from inadequate nutrient management practices and limited agronomic knowledge. Our objective was to quantify nutrient requirements for mature oil palm plantations as a basis to design a decision support tool (DST) for fertilizer recommendations. To do so, we investigated relationships between yield and nutrient accumulation and removal using a large database collected from oil palm plantations in Southeast Asia and West Africa (n = 669 observations) and derived requirements for nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg). We found robust relationships between yield and nutrient accumulation and estimated that 5 (N), 0.5 (P), 6 (K), and 0.7 (Mg) kg per Mg of FFB are required for plantations targeting 75% of their yield potential. Based on these findings, we designed a DST that provides site-specific fertilizer recommendations for smallholders based on yield level and available fertilizer sources, requiring a minimum set of data inputs. Implementation of the tool has the potential to narrow the current yield gap and promote sustainable intensification, ultimately supporting economic growth and improving smallholder livelihoods.
Advisor: Patricio Grassin
Keanekaragaman Flora Pada Berbagai Tingkat Kepadatan Tanah Di Hutan Pegunungan Taman Nasional Bromo Tengger Semeru (TNBTS)
Full text linkDegradasi hutan merupakan faktor pembatas dari keberlanjutan ekosistemyang menyebabkan penurunan kualitas tanah, keanekaragaman hayati (flora dan fauna), dan fungsinya sebagai penyedia kebutuhan pokok dan jasa lingkungan. Keberhasilan upaya restorasi hutan yang akan dilakukan di TNBTS perlu dimonitor dan dievaluasi, untuk itu dibutuhkan beberapa informasi kondisi awal baik dari aspek tanah dan keanekaragaman flora sebelum dilakukan restorasi. Tujuan penelitian ini adalah mengkaji keanekaragaman flora pada berbagai stadia pertumbuhan di berbagai tingkat kepadatan tanah di kawasan hutan degradasi dibandingkan dengan kawasan hutan utuh di TNBTS, sebagai baseline dari upaya restorasi kawasan. Penelitian dilaksanakan di TNBTS, Pasuruan, Jawa Timur tepatnya pada dua resort pengelolaan yaitu RPTN Coban Trisula dan RPTN Pananjakan. Pengambilan data dilakukan dari bulan September 2016 hingga Desember 2016. Rancangan yang digunakan adalah rancangan tersarang (Nested Sampling Design) dengan 3 faktor sumber keragaman (SK) yaitu jenis hutan (hutan degradasi dan hutan utuh), kelerengan (Lereng tengah dan bawah) dan kedalaman tanah (0 - 10 cm; 10 - 20 cm; 20 - 30 cm). Pengamatan diulang 4 kali pada 4 Kawasan Konservasi yang berbeda (KK1, KK4, KK5A, dan KK5B), sehingga total pengukuran sebanyak 16 plot dengan 48 sampel tanah. Variabel yang diukur dari aspek flora yaitu indeks nilai penting (INP), indeks keanekaragaman jenis (H), indeks kekayaan jenis (R) dan indeks kemereataan jenis (E) dan dari aspek tanah yaitu berat isi, berat jenis, porositas, ketahanan penetrasi tanah, C-organik dan pH tanah. Berdasarkan hasil penelitian diketahui bahwa rata - rata indeks keanekaragaman jenis (H) di hutan degradasi lebih rendah jika dibandingkan dengan hutan utuh. Indeks H di hutan degradasi bervariasi tergantung dari stadia pertumbuhannya, untuk stadia semai tergolong „sedang‟(H‟=1,68), dan untuk stadia sapihan pancang dan pohontergolong „rendah‟ (H<1). Indeks H di hutan utuh tergolong „sedang‟ untuk stadia pertumbuhan semai, sapihan, pancang dan pohon (1<H<3). Di hutan degradasi, ada 3 jenis flora yang mendominasi yaituStyphellia javanica (stadia semai, INP=85%), pisang atau Musa paradisiaca (pancang, INP=193%), dan mentigen atau Vaccinium varingiaevolium (sapihan dan pohon, INP=147% dan 300%). Di hutan utuh didominasi oleh Eupatorium riparium (semai, INP=105%), Pilea melastomoides (sapihan, INP=146%),Pinanga coronata(pancang, INP=193%), dan Acacia decurrens (pohon, INP=287%).Tanah di kedua jenis hutan di TNBTS memiliki tingkat kepadatan yang rendah, BI tanah rata-rata 0,82 g cm-3, porositas tanah 63%, serta penetrasi tanah 0,10 MPa. Sekitar 20% penurunan jumlah jenis pohon di hutan TNBTS berhubungan dengan peningkatan penetrasi tanah (R=0,2101), namun hal tersebut tidak terjadi pada stadia semai, sapihan dan pancang
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Kajian Kerapatan dan Keragaman Organisme Tanah Gambut di Bawah Tegakan Tanaman Kelapa Sawit Menghasilkan
Full text linkThis study was conducted on peat land in Kebun Panai Jaya, PT Perkebunan Nusantara IV, North Sumatera province. The sampling method was Pit Fall Trap to trap ground level fauna, Barlese Tullgren to observe the active soil fauna in the soil, and making a soil hole to get the worms sample. The Pit Fall Trap could collect the highest number of the fauna. The soil fauna was positively correlated to temperature, soil moisture, and soil respiration, and it was negatively correlated to soil pH and C/ N ratio. This study showed that, among the soil fauna that found on the observed field, the dominated organisms are weaver ants and followed with earthworms. Both soil fauna (macro and mesofauna) and eukaryotic soil microorganism (fungi and bacteria) were highly found under the frond piles of oil palm plantation.Penelitian ini dilaksanakan di lahan gambut pada Kebun Panai Jaya, PT Perkebunan Nusantara IV, Provinsi Sumatera Utara. Metode pengambilan sampel yang digunakan dengan cara Pit Fall Trap (untuk menjebak fauna permukaan tanah), Barlese Tullgren (untuk melihat fauna tanah yang aktif di dalam tanah) dan membuat lubang (untuk mendapatkan cacing). Metode yang mendapatkan fauna terbanyak yaitu dengan cara Pit Fall Trap. Fauna tanah berkorelasi positif terhadap suhu, kadar air dan respirasi tanah, sedangkan terhadap pH dan C/N berkorelasi negatif. Hasil penelitian menunjukkan, diantara fauna tanah pada plot penelitian, diketahui bahwa jumlah fauna yang paling mendominasi adalah semut rangrang dan diikuti oleh cacing tanah. Baik fauna tanah (makrofauna dan mesofauna) dan mikroorganisme eukariotik tanah (jamur dan bakteri) ditemukan paling banyak pada areal rumpukan kebun kelapa sawit
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