Judul: Model Lintas Transformasi Unsur Fosfor Tanah Kaolinitik dan Smektitik
Abstrak: Phosphorus (P) is one of essentials needed in a sufficient amount to normal plant growth. The objective of this research was to path modelling caolinitic and smectitic soils P transformations. Path diagrams were able to describe soil P transformations, Its elaboration resulted in structural equation models which were P transformations path models. The models parameters estimated using Partial Least Square (PLS). Bartlett's test and KMO showed not all variables used had multicolinearity. Only P-uptake (X1), Po-NaHCO3 (X5), Pi-NaHCO3 (X6), Pi-NaOH (X7), P-occluded (X8), P-HCl (X9) from caolinitic and P-uptake (X1), Po-NaHCO3 (X5), Pi-NaHCO3 (X6), Pi-NaOH (X7), P-HCl (X9) from smectitic which included in path modelling.
Keyword: smectitic soils, phosphorus transformations, path analysis, partial least square, caolinitic soils

Judul: Perubahan Fraksi Fosfor Lambat Tersedia pada Tanah Tergenang yang Diameliorasi Bahan Organik
Abstrak: The low availability and easily fixed phosphorus (P) in soil resulted in heavy and continuous P fertilization by farmers, leading to accumulation of residue-P in soil. In such condition, further P fertilization will not result in higher plant productivity known as leveling off. One way to increase the availability of residual P in soil is to add organic matter. There are various forms of P in the soil, from soluble to unavailable phosphorus can also be differenciated as inorganic and organic forms, where the sum of both referred as total-P. The objective of this research was to study the changes of slow-available phosphorus fraction in a submerged soil ameliorated with organic matter effect of organic matter (extracted with 0.1 M NaOH). Research unit was 200 g (oven-dry, 105°C) in a 10 cm pot. The soil was treated with 0, 500, 750, 1000, 2000, and 5000 kg/ha, and submerged for 5 weeks. Every week for 5 weeks, subsample of each research unit was extracted for determination of NaOH-P following Tiessen and Moir 1993 procedure. The results showed that in general NaOH-Pi, NaOH-Po, and NaOH-Pt increase with increasing organic matter treatments. There was a dynamic pattern of NaOH-Pt, NaOH-Pi, and NaOH-Po with the time of submersion, in which in general NaOH-P initially decreased, increased, then finally decreased.
Keyword: Bogor Agricultural University (IPB), Submerged Soil., Organic Matter, NaOH-Pt, NaOH-Po, NaOH-Pi

Judul: Respon Antibodi pada Ayam Broiler yang Divaksinasi Vaksin Rekombinan Infectious Bursal Disease (IBD).
Abstrak: Penelitian ini dilakukan untuk mengevaluasi durasi antibodi asal induk terhadap Avian Influenza (AI) dan mengevaluasi respon antibodi Infectious Bursal Disease (IBD) pada ayam broiler yang divaksinasi dengan vaksin IBD rekombinan. Penelitian ini meggunakan dua kelompok ayam broiler: kelompok divaksinasi dan kelompok kontrol. Kelompok yang divaksinasi menerima vaksinasi herpesvirus of turkey (HVT)-IBD pada usia satu hari dan kelompok kontrol tidak divaksinasi apapun. Sampel serum diambil pada hari ke 3, 6, 9, 12, 15, 19, 22, 26, 29, dan 33. Keberadaan antibodi AI ditentukan dengan uji inhibisi hemaglutinasi (HI), sedangkan keberadaan antibodi IBD ditentukan dengan enzyme linked immunosorbent assay (ELISA). Antibodi AI asal induk pada kedua kelompok terdeteksi dari hari ke 3 hingga hari ke 29, tetapi titer antibodi berada di bawah level protektif 24. Antibodi IBD pada kelompok kontrol, positif dari hari ketiga hingga 33, tetapi rataan titer antibodi turun pada level terendah pada usia 15 hari. Titer antibodi IBD pada kelompok yang divaksinasi positif sampai usia 33 hari. Penelitian ini menunjukkan bahwa keberadaan antibodi AI asal induk tidak dipengaruhi oleh vaksinasi HVT-IBD, dan keberadaan antibodi IBD asal induk tidak memengaruhi keberhasilan vaksinasi HVT-IBD.
Keyword: antibodi, ayam broiler, Avian Influenza, Infectious Bursal Disease, HVT-IBD