Judul: Knowledges, Attitudes, and Practices of Mango Farmers Regarding Pesticide Use in Mango Production Centers of Cirebon District
Abstrak: Aplikasi pestisida merupakan upaya yang paling umum dilakukan petani untuk mengendalikan hama dan penyakit tanaman. Namun, penggunaan pestisida yang tidak tepat dapat berdampak negatif bagi manusia dan lingkungan. Penelitian ini bertujuan menentukan tingkat pengetahuan, sikap dan tindakan petani mangga di Kabupaten Cirebon terhadap penggunaan pestisida. Penelitian dilakukan pada Bulan Februari hingga April 2021 menggunakan metode survei langsung di lapangan melalui wawancara dengan petani mangga menggunakan kuesioner terstruktur. Lokasi pengambilan sampel ditentukan berdasarkan populasi masyarakat yang berprofesi sebagai petani mangga di kecamatan tersebut lebih banyak dibandingkan dengan di kecamatan lainnya dengan jumlah sebanyak 45 responden. Data dimasukan ke dalam Microsoft Excel 2007, lalu dianalisis secara deskriptif dan disajikan dalam bentuk tabel. Hasil penelitian menunjukkan bahwa sebagian besar petani menggunakan pestisida secara intensif dan terjadwal serta menggunakan dosis yang tidak sesuai dengan anjuran sehingga dapat menimbulkan residu pestisida. Sebagian besar petani mangga menggunakan insektisida dengan bahan aktif lambda sihalotrin dan sipermetrin, sedangkan fungisida yang digunakan adalah prokloraz dan azoksistrobin., Pesticide application is the most frequent method to control plant pests and diseases. However, improper use of pesticides can cause negative effects on both human health and the environment. This study aimed was to evaluate the knowledge, attitudes, and behaviors of mango farmers in Cirebon Regency regarding pesticide use. The study has been conducted from February to April 2021 using a direct survey method through interviews with mango farmers using a structured questionnaire. Respondents were determined based on the farmer population who work as mango farmers in the village, with a total of 45 respondents. The data was entered into Microsoft Excel 2007, then analyzed descriptively and presented in tabular form. Results showed that most of the farmers were using pesticides intensively regularly (calendar system) using doses that are not as recommended. The active ingredients of lambda-cyhalothrin and cypermethrin (insecticides) and prochloraz and azoxystrobin (fungicides) are commonly used by mango farmers.
Keyword: active ingredient, interview, pesticide application

Judul: Knowledge, Attitudes and Practices of Farmers in  the use of pesticides on Citrus Plantations in Simalungun Regency
Abstrak: Jeruk (Citrus spp.) merupakan tanaman tahunan yang tergolong kedalam famili Rutaceae. Serangan hama pada tanaman jeruk merupakan salah satu faktor penting yang harus diperhatikan untuk mempertahankan bahkan untuk meningkatkan hasil dengan kualitas dan kuantitas yang optimal. Penurunan produktivitas jeruk sering terjadi yang salah satunya diakibatkan oleh serangan organisme pengganggu tanaman (OPT). Pengendalian OPT baik hama maupun penyakit pada tanaman jeruk dilakukan oleh petani menggunakan pestisida. Penggunaan pestisida harus mengikuti rekomendasi yang telah ditentukan karena apabila tidak sesuai maka dapat menyebabkan berbagai dampak negatif. Penelitian ini bertujuan mempelajari pengetahuan, sikap dan tindakan petani dalam penggunaan pestisida untuk pengendalian OPT pada pertanaman jeruk di Kabupaten Simalungun, Sumatera Utara. Penelitian dilaksanakan pada bulan Mei hingga Agustus 2021 menggunakan metode survei langsung di lapangan dengan kuesioner terstruktur untuk mendapatkan data primer. Penentuan lokasi pengambilan contoh dilakukan secara terpilih (purposive) yang didasarkan pada populasi penduduk yang bekerja sebagai petani jeruk di tiga kecamatan yaitu Kecamatan Pematang Silimahuta, Purba, dan Silimakuta. Petani responden yang dipilih secara acak berjumlah 50 orang. Data yang diperoleh kemudian dianalisis secara deskriptif untuk mendeskripsikan tingkat pengetahuan, sikap dan tindakan petani dalam penggunaan pestisida. Secara umum petani responden memiliki pengetahuan, sikap dan tindakan yang cukup baik dalam penggunaan pestisida. Sebagian besar petani mengendalikan hama dan penyakit menggunakan pestisida sintetik dengan bahan aktif abamektin dan sipermetrin., Citrus (Citrus spp.) is an annual plant belonging to the Rutaceae family. Pest infestation on citrus plants is one of the important factors that must be considered in order to increase the high citrus production, both in quality and quantity. The decrease of citrus productivity often occurs due to plant pest and disease attacks. Generally farmers control the pests using synthetic pesticides. The use of synthetic pesticides is a common method used by farmers to control pests and diseases in citrus plants. The application of pesticides must follow the recommendations. However, the improper and exceesive uses of pesticides can cause various negative impacts, one of which is pesticide residues. This study aimed to study the knowledge, attitudes and practices of farmers in the use of pesticides in pest management of citrus plantations in Simalungun Regency, North Sumatra. The research was conducted from May to August 2021 using a direct survey method in the field using a structured questionnaire to obtain primary data. The respondents were selected using purposive sampling based on the population who worked as citrus farmers in the three selected sub-districts, namely Pematang Silimahuta, Purba, and Silimakuta sub-districts. The number of respondent farmers selected was 50 people. Data obtained were then descriptively analysis to describe the level of knowledge, attitudes, and practices of farmers in the use of pesticides. In general, respondents had good knowledge, attitudes and practices in the use of pesticides. Most farmers used synthetic pesticides with active ingredients of abamectin and cypermethrin in order to control the pests.
Keyword: negative impact, pesticide application, plant pests and diseases

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.
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