Judul: Perubahan Ciri Kimia dan Efisiensi Pemupukan P  pada Tanah Typic Hapludox Sitiung Sumatera Barat  Melalui Pemberian Kalsium Karbonat dan  Kalsium Sulfat
Abstrak: Penelitian ini bertujuan untuk : (1) mempelajari perubahan ciri-ciri kimia dan efisiensi pemupukan P tanah Oxisols akibat pengaruh pemberian kalsium karbonat dan kalsium sulfat, (2) mempelajari respons tanaman jagung akibat pemberian kalsium karbonat dan kalsium sulfat dan pemberian pupuk P (SP36 dan fosfat alam Ciamis).
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Judul: Perubahan kapasitas tukar kation dan kadar fosfat tanah akibat perlakuan pupuk organik dalam sistem budi daya sayuran organik
Abstrak: Budi daya pertanian organik perlu dikembangkan, demi mempertahankan produktivitas dan kesuburan lahan pertanian dalam jangka panjang. Untuk kesuksesan program ini, diperlukan informasi mengenai metode pemupukan yang tepat dan efisien. Dalam penelitian ini, enam perlakuan pemupukan diamati kemampuannya dalam meningkatkan parameter kimiawi mutu tanah, meliputi kapasitas tukar kation (KTK), kadar fosfat tersedia, fosfat ekstrak HCl 25%, dan kalium ekstrak HCl 25%. Kationkation yang diikat oleh koloid tanah diekstraksi dengan larutan amonium asetat pH 7, dan diukur kadarnya menggunakan spektrofotometer serapan atom (AAS). Ekstraksi lebih lanjut dengan larutan NaCl 10% dilakukan untuk mendapatkan nilai KTK, yang diukur menggunakan spektrofotometer ultraviolet tampak (UV-Vis). Kadar fosfat ekstrak Bray I dan ekstrak HCl 25% diukur menggunakan spektrofotometer UV-Vis, sedangkan kalium ekstrak HCl 25% diukur dengan AAS. Hasil analisis statistika menunjukkan bahwa perlakuan yang diberikan tidak menghasilkan perubahan yang nyata terhadap parameter kimiawi mutu tanah. Dalam hal ini, faktor cuaca selama musim tanam sangat besar pengaruhnya. Namun, jika dilihat secara keseluruhan, perlakuan pupuk kandang ayam yang diperkaya dengan dolomit dan fosfat alam memberikan hasil terbaik.
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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