Judul: Dinamika Penetrabilitas Tanah pada Berbagai Penggunaan Lahan di Tanah Latosol, Darmaga
Abstrak: Plant roots that functioning to absorb water and nutrients can be inhibited when soil penetrabilty is quite high. Soil penetrability can be affected by soil properties, for example texture, bulk density, organic matter content, soil water content, matrix potential, calcium carbonate, and types of clay mineral. Of the soil properties, there are some that can be influenced by the type of land use. This study examined the penetrability of soil in various land uses. There was a series of observation of soil penetrability and soil properties in a variety of land use conducted in this research in order to study the relationship of soil properties on soil penetration resistance, soil water content relationship with penetrability, and resistance dynamics of land penetration in various land uses. The results showed that the soil texture class in the three land uses was clay. The highest clay percentage was found in grasslands both in the depth of 0-10 cm (82.00%) and 10-20 cm (81.90%). The highest soil bulk density in the depth of 0-10 cm was found in grasslands (1.09 g/cm3) and in the depth of 10-20 cm was found in mixed farms (1.13 g/cm3). The organic matter content in the depth of 0-10 cm was found in mixed farms (4.80%) and in the depth of 10-20 cm was found in secondary forest (3.18%). The index of soil aggregate stability of the three land uses were classified as a very stable class. Soil total pore space in the depth of 0-10 cm was found in secondary forest (61.52%) and in the depth of 10-20 cm was found in grasslands (59.15%). The three land uses had higher micro pore compared to the micro pore them selves. The different properties of soil had different effects on soil penetration resistance. Grassland showed the highest value of soil penetrability because of its high level of soil bulk density and clay. Secondary forest had the lowest soil penetrability value due to its high soil organic matter, low soil density, low micro pore space, and very stable soil aggregates. The relationship of soil penetration resistance with water content in three land uses was presented in power regression models with different determination coefficient. In the depth of 0-10 cm, the relationship had R2 of 0.53 in secondary forest, 0.35 in mixed farms, and 0.19 in grasslands. In the depth of 10-20 cm, the relationship of soil penetrability with moisture content had R2 of 0.29 in secondary forest, 0.26 in garden mix, and 0.11 in grasslands. In the days of no rain, the resistence of soil penetration had increased sharply since the third day in secondary forests, since the fifth day in mixed farms, and since the fourth day in grasslands in 0-20 cm deep. The resistence of soil penetration at each land use after 12 days of no rain increased because the soil was drier and harder, however, it did not inhibit the growth of plant roots.
Keyword: physical properties of soil, land use, penetration resistance, water content, Bogor Agricultural University (IPB)

Judul: Analisis Sifat Fisik Tanah pada Empat Penggunaan Lahan di Kebun Pendidikan Cikabayan IPB
Abstrak: Institut Pertanian Bogor banyak memanfaatkan lahan untuk menunjang pendidikan mahasiswa, salah satunya yaitu Kebun Pendidikan Cikabayan yang digunakan untuk kegiatan pembelajaran mahasiswa dan penelitian. Beberapa kondisi di lapangan memiliki sifat-sifat tanah yang dapat berubah terutama diakibatkan oleh pengolahan tanah. Pemadatan tanah merupakan suatu bentuk degradasi kualitas tanah terkait pengolahan tanah. Pemadatan tanah dapat menjadi masalah karena akan menghambat perkembangan akar yang dapat memengaruhi hasil tanaman. Pemadatan tanah dapat diidentifikasi melalui pengukuran ketahanan penetrasi tanah dan kekuatan geser tanah. Penelitian bertujuan melihat keterkaitan karakteristik sifat-sifat fisik tanah terhadap kuat geser tanah dan penetrasi tanah pada empat penggunaan lahan yakni lahan karet, kelapa sawit, perkebunan intensif dan lahan konservasi. Hasil menunjukkan bahwa tekstur tanah pada keempat penggunaan lahan adalah klei dan bersifat kohesif. Sifat kohesif yang terdapat pada fraksi klei mempengaruhi kuat geser tanah dan penetrabilitasnya. Lahan kebun karet memiliki nilai penetrasi (86.81 kPa) dan kuat geser (62.56 kPa) yang lebih tinggi dibandingkan penggunaan lahan lainnya akibat perakaran karet yang sangat rapat dengan vegetasi penutup lahan yang lebih banyak. Nilai sensitivitas tanah pada lokasi penelitian berkisar antara 1.64-2.14. Lahan kebun karet memiliki nilai sensitivas sebesar 2.14 sehingga termasuk dalam kelas sedang, artinya berpotensi kehilangan massa tanahnya lebih tinggi dibandingkan penggunaan lahan lainnya., In order to facilitate student education, Bogor Agricultural University uses a lot of land for agriculture research station, one of which is the Cikabayan Research Station which is used for student learning activities and research. Several conditions in the field may lead to change some of soil properties mainly due to soil tillage. Soil compaction is a form of soil degradation related to soil tillage. Soil compaction can be an issue because impede root growth and lower agricultural yields. By evaluating the soil's shear strength and penetration resistance, soil compaction can be detected. This study's objective was to investigate the connections between the physical characteristics of the soil, its shear strength, and soil penetration in four different land uses, including rubber, oil palm, intensive plantations, and conservation lands. The result demonstrated that the four land uses' soil textures were clay and cohesive. The cohesiveness in the clay fraction have an impact on the soil's shear strength and soil penetration. Rubber plantation land has a penetration value of 86.81 kPa and shear strength of 62.56 kPa which is higher than other land uses due to very dense rubber roots with more land cover vegetation. Rubber plantation land has a sensitivity value of 2.14. Rubber plantation land is classified as moderately sensitive, it has a larger potential for soil mass loss than other land uses.
Keyword: physical characteristics, soil shear strength, soil penetration resistance

Judul: Pengklonan gen VP28 Penyandi Viral Protein-28 dari virus white spot syndrome sebagai langkah awal produksi vaksin rekombinan udang penaeid
Abstrak: Usaha produksi udang dalam negeri saat ini sedang mengalami kendala akibat serangan penyakit white spot syndrome virus (WSSV) pada jenis udang windu (Penaeus monodon). WSSV yang termasuk virus DNA berukuran besar dapat menginfeksi udang dan berbagai jenis crustaceae lainnya. Virus ini merupakan patogen yang sangat ganas dan paling serius menyerang udang. Serangannya begitu cepat, sangat sulit dihentikan dan dapat mematikan 100% udang peliharaan dalam waktu 3-10 hari setelah munculnya gejala klinis. Serangan virus ini juga telah menghancurkan industri udang di berbagai negara. Infeksi WSSV ditandai dengan adanya bintik putih atau bercak putih pada eksoskeleton dan epidermis terutama pada bagian karapas udang. Hingga saat ini belum ada cara tradisionalyang efektif mencegah dan menanggulangi penyakit ini.
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