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 bahan pemantap tanah (Soil Conditioner) terhadap beberapa sifat fisik dan penetrasi akar padi gogo IR-36 pada tanah podsolik merah kuning (Typic Humitropept) dari Jasinga
Abstrak: Tujuan Penelitian ini adalah untuk mengamati pengaruh bahan pemantap tanah (soil conditioner) terhadap sifat- sifat fisik tanah, seperti bobot isi, distribusi ukuran pori, Angka Atterberg, nilai COLE, kemantapan agregat, dan kekuatan tanah, serta melihat pengaruhnya terhadap penetrasi akar Padi Gogo IR-36. Percobaan dilakukan di Rumah Kaca, Jurusan Tanah pada akhir Oktober 1987 akhir Januari 1988. Analisis sifat fisik tanah dilakukan di Laboratorium Fisika Tanah, Jurusan Tanah, Fakultas Pertanian, IPB; dan Laboratorium Konservasi Tanah dan Air, Pusat Penelitian Tanah. Analisis sifat ini dimulai dari awal Februari sampai April 1988. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap. dijelaskan sbb: Perlakuan bahan pemantap tanah dapat a (kontrol), b (S1 Semen dengan dosis 2 ton/ha), c (S2 = Semen dengan dosis 7 ton/ha), d (21 = Zeolit dengan dosis 15 ton/ha), e (Z2 = Zeolit dengan dosis 30 ton/ha), ₤ (K1 Sampah kota dengan dosis 10 ton/ha), g (K2 = Sampah kota dengan dosis 15 ton/ha), h (P1 = Kotoran ayam dengan dosis 10 ton/ha), i (P2 = Kotoran ayam dengan dosis 15 ton/ha). Jumlah perlakuan seluruhnya sebanyak 9 perlakuan. Percobaan ini diulang 3 kali, sehingga jumlah keseluruhan satuan percobaan 27 buah. Pemberian bahan pemantap tanah tidak nyata mempengaruhi bobot isi, pori drainase sangat cepat dan lambat, air tersedia, aerasi tanah, kekuatan tanah, dan penetrasi akar Padi Gogo IR-36. ...
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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