Judul: Pemilihan peubah sifat kimia tanah dengan mempertahankan konfigurasi data asal: studi kasus data tanah mineral terdegradasi dari Jawa Barat dan tanah gambut dari air Sugihan Kiri, Sumatera Selatan
Abstrak: Ada banyak peubah sifat kimia tanah yang biasanya diamati, yaitu pH H₂O, KTK (Kapasitas Tukar Kation), kandungan-kandungan N-total, Ca-, K-, Na-, Mg-, Al-, H-dapat dipertukarkan(dd), Fe, C-Organik, Cu, Zn, Mn, Pirit dan S, serta KB (Kejenuhan Basa) dan nisbah C/N. Sebagian dari peubah tersebut diperkirakan dapat menggambarkan keragaman data asal.
Keyword: Chemical soil

Judul: The Chemical Properties of Soil in Taliwang Distric, West Sumbawa Regency on Land Use of Teakwood Plantation, Dryland, and Paddy Soils.
Abstrak: Sifat kimia tanah berperan besar dalam menentukan kesuburan tanah. Kesuburan tanah secara kimia dinilai dari kandungan nitrogen, fosfor, basa dapat ditukar (K, Ca, Mg, dan Na), pH tanah, karbon organik, dan kapasitas tukar kation. Penelitian ini bertujuan mengkaji sifat kimia tanah di Kecamatan Taliwang, Kabupaten Sumbawa Barat pada tiga penggunaan lahan berbeda yaitu Kebun Jati (L1), Ladang (L2), dan Sawah (L3). Penelitian ini dilaksanakan pada September 2020 hingga Maret 2021. Contoh tanah diambil pada L1 dan L2 masing-masing empat lapisan, sedangkan pada L3 tiga lapisan. Analisis kimia tanah dilakukan di Laboratorium Kimia dan Kesuburan Tanah, IPB University. Hasil penelitian menunjukkan bahwa pH tanah umumnya berkisar agak masam hingga netral (6,4- 7,3), nilai pH tanah sawah cenderung nertral sedangkan nilai pH tanah kebun jati dan ladang tergolong agak masam. Kandungan C-organik tergolong rendah hingga tinggi (0,93% - 4,09%), kandungan N-total tergolong sangat rendah hingga sedang (0,07%-0,21%). Nilai P-tersedia tergolong sangat rendah pada semua contoh tanah (0,09 ppm-1,31 ppm). Rendahnya nilai P-tersedia pada lokasi penelitian diduga karena P diikat menjadi bentuk tidak larut oleh basa-basa seperti Ca dan Mg yang kandungannya tinggi di dalam tanah yang diamati. Di samping itu karena tanah yang diamati merupakan tanah yang berkembang dari bahan induk yang miskin akan unsur P. Nilai KTK tanah berkisar dari 13,9 cmol(+)/kg sampai 30,4 cmol(+)/kg. Nilai KB tanah yang diamati tergolong sangat tinggi yaitu lebih dari 100% dan tergolong tinggi sampai sangat tinggi. Kebun jati memiliki kandungan karbon organik, N-total, P-tersedia, basa dapat ditukar dan KTK lebih tinggi dibandingkan dengan ladang dan sawah. Kandungan karbon organik, N-total, dan P-tersedia yang termasuk kategori rendah pada penggunaan lahan kebun jati, ladang, dan sawah harus menjadi perhatian utama dalam pengelolaan tanah di Kecamatan Taliwang, Kabupaten Sumbawa Barat. Kata kunci: Basa dapat ditukar, Karbon organik, Kapasitas tukar kation, N-total, pH tanah, P tersedia., The soil chemical properties play a major role in determining soil fertility. Soil fertility is characterized chemically by the nitrogen and phosphorus content, exchangeable bases (K, Ca, Mg, and Na), soil pH, organic carbon, and cation exchange capacity (CEC). This research was aimed to examine the chemical properties of soil in Taliwang District, West Sumbawa Regency on three different land uses, namely teakwood plantation (L1), dryland (L2), and paddy soil (L3). The study was conducted from September 2020 to March 2021. Soil samples were taken at L1 and L2 each from four layers (horizons), while in L3 soil samples were taken from three layers. Soil chemical properties analysis was conducted at the Laboratory of Soil Chemistry and Fertility, IPB University. The results showed that the pH of the soil were generally ranged from slightly acidic to neutral (6.4-7.3), the pH value of paddy soil is neutral while the pH value of teakwood plantation soil and dryland soil is relatively slightly acidic. Organic carbon of soil samples of three landuse observed is relatively low to high (0.93%-4.09%), the total nitrogen content is classified as very low to moderate (0.07%-0.21%). The available-P value is very low in all soil samples (0.09 ppm-1.31 ppm). The low value of available-P at the research site due to the high
Keyword: Available-P, Carbon organic, Cation exchange capacity, Exchangeable bases, Soil pH, Total-N

Judul: Pengembangan Kultur sel dan Vaksin Inaktif untuk Pencegahan Infeksi Megalocytivirus pada Ikan Gurami (Osphronemus goramy).
Abstrak: Megalocytivirus of family Iridoviridae is a known pathogen that caused fatal systemic infection lead to massive death and significant economic losses of numerous fish species in marine, fresh water and ornamental fish industries. In Indonesia, since 2011 megalocytivirus had been found as main pathogen in some cases of giant gourami outbreak especially in West Java, Central Java and Bali. Rapid expansion and intensification in aquaculture has led to many cases of disease outbreaks. Mortality rates of fish due to viral infections is high and up to now there’s no effective treatment methods to overcome the problem. Prevention is a better choice than treatment although efforts to prevent and control diseases caused by viral infections are still difficult to do. The aim of this study was to develop a primary cell culture and an inactivated vaccine for megalocytivirus infection in giant gourami. The first stage of this study was conducted to identify and characterized megalocytivirus in cultured giant gourami. The virus was identified using universal and spesific primers for megalocytivirus and infectious spleen and kidney necrosis virus (ISKNV). Sequencing and BLAST analysis were used to develop phylogenetic tree. The result showed that phylogenetic analysis of major capsid protein (MCP) gene unveiled a new megalocytivirus strain, designated as giant gourami iridovirus (GGIV). GGIV formed cluster belonged to ISKNV and has 100% homology to ISKNV complete genome. Artificial infection by intraperitoneally injection with supernatant homogenate from spleen and kidney of naturally infected fish were showed 93% mortality in 12 days. Fish showed clinical sign of infection as lethargic, loss of appetite, pale or darken body color and haemorrhages. Internal organ on death fish showed swollen spleen and kidney and also pale liver. Quantitative PCR analysis on internal organs showed spleen had the highest viral DNA copy number followed by kidney, gill and liver. Histopathological analysis showed hemorrage in these organs and many abnormally hypertrophied cells which is typical histopathological characteristic of megalocytivirus infection. On the second stage of this study was to develop primary cell cultures from its spleen as target organ for propagating megalocytivirus in vitro. We developed primary cell from spleen by enzimatic dissociation. The result showed that primary cell (GPs cell) can grow well at 27 oC and 10% serum in L-15 medium was sufficient for cells growth. GPs cells were infected with giant gourami iridovirus (GGIV) showed enlargement and rounding cells. Virus propagated in GPs cells was highly virulent when injected to giant gourami in artificial infection. Intraperitoneal injection experiments of diluted virus supernatant showed 100% mortality within 7-11 dpi and 97% mortality in 21 days by cohabitation with abnormalities were observed in spleen and kidney. GPs cell was successfully subcultured for more than 30 passages and was found to be susceptible to GGIV as a pathogen of ISKNV infection in cultured-giant gourami. GGIV was propagated in GPs cells for megalocytivirus vaccine development for giant gourami. On the third stage of this study was to develop an effective vaccine and measure its efficacy using relative percent survival (RPS), serological parameters (antibody titers), and molecular (relative expression of gouramy immune genes). The
Keyword: inactivated-vaccine, megalocytivirus, primary cell culture, Osphronemus goramy