Judul: Pests and Diseases of Glutinous Rice Cv. of  Grendel at Various Plant Spacing, Nitrogen and Potassium Fertilizing Doses.
Abstrak: Pemupukan dan pengaturan jarak tanam merupakan aspek penting untuk produksi padi. Penelitian bertujuan mengkaji pengaruh jarak tanam, pemupukan Nitrogen dan Kalium terhadap populasi atau tingkat serangan hama dan penyakit padi. Penelitian dilakukan di Desa Kiarasari, Kecamatan Compreng, Kabupaten Subang pada bulan November 2022 sampai dengan Januari 2023 menggunakan rancangan acak kelompok dengan empat taraf pemupukan dan dua taraf jarak tanam. Hasil penelitian menunjukkan ada pengaruh nyata pemupukan dan jarak tanam terhadap tingkat serangan penggerek batang padi kuning, blas daun, dan hawar daun bakteri, tidak berpengaruh nyata terhadap populasi wereng batang cokelat dan jumlah kelompok telur penggerek batang. Perlakuan yang berpengaruh nyata menurunkan serangan penggerek batang padi kuning adalah F3T2 (90 kg/ha N + 35 kg/ha K dan 50 cm x 25 cm). Perlakuan yang berpengaruh nyata menurunkan keparahan penyakit blas daun adalah F4T2 (135 kg/ha N + 52,5 kg/ha K dan 50 cm x 25 cm). Perlakuan yang berpengaruh nyata menurunkan keparahan keparahan penyakit hawar daun bakteri adalah F2T1 (45 kg/ha N + 17,5 kg/ha K dan 40 cm x 40 cm) dan F3T1 (90 kg/ha N + 35 kg/ha K dan 40 cm x 40 cm)., Fertilizing and plant spacing are important aspects for rice production. The research aims to examine effect of plant spacing, Nitrogen and Potassium fertilizing on the population or damage level by rice pests and diseases. The research was conducted in Kiarasari Village, Compreng District, Subang Regency from November 2022 to January 2023 using a randomized block design with four levels of fertilizing and two levels of plant spacing. The results showed that there was a significant effect of fertilization and plant spacing on the level of damage by stem borers, leaf blast, and bacterial leaf blight, but had no significant effect on the population of brown planthoppers and the number of stem borer egg clusters. The treatment that has a significant effect on reducing yellow rice stem borer attacks was F3T2 (90 kg/ha N + 35 kg/ha K and 50 cm x 25 cm), on reducing leaf blast severity was F4T2 (135 kg/ha N + 52.5 kg/ha K and 50 cm x 25 cm), and on reducing bacterial leaf blight severity were F2T1 (45 kg/ha N + 17.5 kg/ha K and 40 cm x 40 cm) and F3T1 (90 kg/ha N + 35 kg/ha K and 40 cm x 40 cm).
Keyword: blas daun, hawar daun bakteri, penggerek batang padi, bacterial leaf blight, leaf blast, rice stem borer

Judul: Controlling of Blast Disease (Pyricularia oryzae Cav.) in Lowland Rice with Several Cultivation Methods
Abstrak: Padi merupakan sumber pangan utama yang penting bagi masyarakat Indonesia. Oleh karena itu keberlanjutan produksinya dari tahun ke tahun selalu menjadi perhatian bagi pemerintah. Faktor yang dapat memengaruhi produktivitas padi salah satunya adalah serangan hama dan penyakit tanaman. Penyakit blas yang disebabkan oleh Pyricularia oryzae merupakan penyakit penting pada tanaman padi di negara-negara penghasil padi di seluruh dunia. Saat ini terdapat tiga cara utama yang dapat dilakukan untuk mengendalikan penyakit blas, yaitu teknik budidaya, penggunaan fungisida dan varietas tahan. Percobaan lapangan ini dilakukan untuk mengetahui pengaruh beberapa teknik budidaya tanaman padi terhadap perkembangan penyakit blas. Percobaan ini dilakukan dengan menggunakan rancangan acak lengkap satu faktor dengan tiga perlakuan dan tiga ulangan. Perlakuan tersebut yaitu P1 (pengembalian jerami, penggunaan pupuk hayati, pengurangan pupuk sintetis, tanpa penggunaan pestisida sintetis), P2 (pengembalian jerami, penggunaan pupuk dan pestisida sintetis sesuai dengan cara petani setempat), dan P3 (jerami dibakar, penggunaan pupuk dan pestisida sintetis sesuai dengan cara petani setempat). Data tingkat serangan blas daun, blas leher, tinggi tanaman, jumlah anakan total dan jumlah anakan produktif pada setiap ulangan diamati pada 50 rumpun tanaman contoh yang ditentukan secara sistematis. Pengamatan tersebut dilakukan pada umur 30, 40, 60, 80, dan 90 hari setelah pindah tanam. Perlakuan yang diuji cobakan tidak menunjukkan perbedaan yang nyata terhadap insidensi dan keparahan penyakit, baik blas daun maupun blas leher, tinggi tanaman, total jumlah anakan serta jumlah anakan produktif. Perlakuan P2 menunjukkan produktivitas gabah kering panen maupun kering giling yang paling tinggi dibandingkan dua perlakuan lainnya., Rice is an important main food source for Indonesian people. Therefore, the sustainability of production from year to year is always a concern for the government. One of the factors that may affect rice productivity is the presence of pests and plant diseases. Blast disease caused by Pyricularia oryzae is an important disease in rice-producing countries around the world. At present, there are three primary control measures that may be applied, namely cultural practices, fungicides and cultivar resistance. This field experiment was conducted to determine the effect of several rice cultivation techniques on the development of blast disease. This experiment was conducted using a one-factor completely randomized design with three treatments and three replications. The treatments were P1 (returning straw to the field, using biological fertilizers, reducing synthetic fertilizers, without the use of synthetic pesticides), P2 (returning straw to the fields, using synthetic fertilizers and pesticides with the dosage as commonly practiced by local farmers), and P3 as comparison treatment (cultivation techniques commonly practiced by local farmers include burning straw, use of synthetic fertilizers and pesticides with doses as commonly practiced by local farmers). Data on incidence and severity of leaf blast and neck blast, plant height, number of total tillers and number of productive tillers in each replication were observed on 50 sample plants which were determined systematically. The observations were made at 30, 40, 60, 80, and 90 days after transplanting. The treatments tested did not show significant differences in the incidence and severity of both leaf and neck blast disease, plant height, total number of tillers and number of productive tillers. The P2 treatment showed
Keyword: bio-fertilizer, blast disease, straw return, synthetic fertilizer, synthetic pesticides

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
Keyword: