Judul: Pengaruh Soil Conditioner Emulsi Bitumen Terhadap Kemantapan Agregat, Kapasitas Menahan Air, Indeks Plastisitas, Peptisasi Dan Flokulasi Serta Cole (Coeffisient Of Linear Extensibility) Pada Tanah Podsolik Merah Kuning Jasinga
Abstrak: Tujuan penelitian ini adalah untuk mengetahui pengaruh berbagai dosis soil conditioner emulsi bitumen terhadap berbagai sifat fisik tanah. Penelitian dilakukan di Rumah Kaca dan Laboratorium Fisika Tanah, tanah yang digunakan adalah tanah Podsolik Merah Kuning Jasinga. Dosis emulsi bitumen yang digunakan adalah 0.0, 3.0, 6.0, 9.0, 12.0, 15.0 dan 18.0 ton/ha. Rancangan penelitian yang digunakan adalah Rancangan Acak Lengkap, dengan uji BNJ dan uji Kontras. Hasil penelitian menunjukkan bahwa emulsi bitumen dapat memantapkan agregat tanah sampai dosis 15.0 ton/ha, meningkatkan kadar air tersedia untuk masa inkubasi 45 hari dan tidak berpengaruh nyata pada inkubasi 90 hari, menurunkan indeks plastisitas tanah, tidak berpengaruh nyata terhadap peptisasi, menurunkan flokulasi dan tidak berpengaruh nyata terhadap nilai COLE. Disarankan ada penelitian lanjutan, terutama untuk melihat pengaruh waktu yang lebih lama terhadap perubahan sifat fisik yang mungkin terjadi…
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Judul: Pengaruh soil conditioner, pengapuran dan tanaman jagung terhadap beberapa sifat fisik tanah podsolik merah kuning dari jasinga
Abstrak: Penelitian ini bertujuan untuk mengetahui pengaruh soil conditioner, pengapuran, dan tanaman jagung serta interaksinya terhadap beberapa sifat fisik tanah Podsolik Merah Kuning. Hasil penelitian ini diharapkan dapat dimanfaatkan sebagai bahan informasi dalam penelitian lebih lanjut tentang penggunaan soil conditioner untuk tanah-tanah di Indonesia. Percobaan dilakukan di kamar kaca dengan menggunakan pot plastik. Senyawa polimer polyvinil alcohol (PVA) di- pakai sebagai soil conditioner, kalsium karbonat (CaCO3). sebagai bahan pengapuran, dan tanaman jagung varietas Hi- brida IPB II (19 x 16) sebagai tanaman uji. Kerusakan tanah akibat erosi akan lebih parah jika pemanfaatan tanah tidak mengenal kaedah-kaedah pengawetan tanah. Kerusakan tanah akibat erosi dapat ditekan dengan jalan memperbaiki sifat fisik tanah, seperti kemantapan agregat dan porositas tanah. Polyvinil alcohol (PVA) dengan dosis 0.30 persen cenderung meningkatkan porositas total, air tersedia, dan kemantapan agregat; sedangkan terhadan bebot isian ruang pori drainase cepat/lambat berakibat menurunkan. Pengaruhnya terhadap bobot jenis partikel tidak nyata. Pengapuran dengan dosis 20.22 ton CaCO3/ha cenderung menurunkan bobot isi dan ruang pori drainase lambat, tetapi meningkatkan porositas total dan indeks stabilitas agregat. Tanaman jagung mengakibatkan jumlah air tersedia dan dan indeks stabilitas agregat lebih besar bila dibandingkan dengan perlakuan yang tidak ditanami jagung.
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Judul: Identifikasi Molekuler Kompleks Spesies Himantura uarnak (Batoidea: Dasyatidae) di Indonesia.
Abstrak: Stingrays are one of the cartilaginous fish, apart of sharks and skates, and one of Indonesia's fishery resources. Almost of elasmobranch fishes are economically important fish. The refined products and live specimens of this fish are a lot of traded. Himantura uarnak, H. undulata and H. leoparda are stingray species in Himantura and Dasyatidae family, which are the most popular stingrays in Indonesia waters. The stingrays are major target species were used as a consumable product and trading products. Levels of species diversity of cartilaginous fish in Indonesia are very high, and also Indonesia is listed as one of the countries that use elasmobranch resources the highest in the world. Generally, this study aims to identify each species of H. uarnak species complex through molecular approaches. While specifically, this study aims to estimate the evolutionary process of species divergence and to determine the relationship between species. The methods were used in this study included field sampling, sample collection, and specimen identification, collection of genetic samples, analysis of genetic samples and data analysis . Size polymorphism nuclear DNA markers (intron EPIC) were used. Polymorphism alleles translated into genotypes and alleles frequency of five introns loci. The results of Bayesian analysis and Correspondence Analysis (CA) produced informative diagram of the population structure showed 4 different clusters. Cluster 1 and 4 were H. leoparda, Cluster 2 indicated as H. undulata and the Cluster 3 was H. uarnak. Cluster 1 was a variant of Cluster 4, in this time called as H. leoparda var.1. Separation of four clusters according to nuclear DNA need to be proved by mitochondria DNA maker by cytochrome c oxidase subunit I (COI) and cytochrome b (cyt b). Molecular approaches were using mitochondrial DNA gene cytochrome c oxidase subunit I (COI) and cytochrome b produced 4 main groups (Group I, II, III and IV). Both of these molecular approaches showed each individual of groups were in consistent clade and the main group. Hence the H. uarnak species complex in Indonesian waters were divided into 4 main groups, and each was a particular species. The Group I and IV were the two group species that have been released as H. leoparda and Group I was H. leoparda var. 1 identified as cryptic species. Group II was one individual who grouped as H. undulata. Group III was one of other group that identified as H. uarnak and in accordance with the morphological characteristic through spotting pettern. Morphological approach to identified the stingrays of Himantura uarnak species complex clearly less accurate than the molecular approaches. Morphological approach should not be used to identify a species complex in stingrays without helped by other approaches.
Keyword: Himantura uarnak species complex, intron EPIC, cyt b, COI, spotting pattern