Judul: The Effect of Leaf Pruning on the Productivity of Three Cowpea Varieties (Vigna unguiculata L. Walp.)
Abstrak: Pemangkasan daun menjadi salah satu upaya yang dapat dilakukan untuk meningkatkan produktivitas kacang tunggak. Penelitian ini bertujuan mengetahui waktu terbaik pemangkasan daun dalam memperoleh produktivitas paling optimal. Penelitian dilaksanakan di Desa Tangkil, Kecamatan Citeureup, Bogor, dari bulan April hingga Juli 2017. Penelitian ini menggunakan rancangan kelompok lengkap teracak (RKLT) dengan dua faktor yaitu varietas (petak utama) dan waktu pemangkasan (anak petak) yang disusun pada petak terbagi (split plot) dengan empat ulangan. Petak utama adalah tiga varietas tanaman kacang tunggak, yaitu KT-2, KT-6, dan KT-8. Anak petak adalah waktu pemangkasan daun, yaitu 4 MST, 6 MST, 8 MST, dan 10 MST. Hasil penelitian menunjukkan pemangkasan daun berpengaruh nyata terhadap peningkatan jumlah polong, bobot kering polong, dan bobot biji kacang tunggak. Komponen hasil paling optimal didapatkan pada tanaman dengan perlakuan pemangkasan tua, yaitu minggu ke 8 dan 10. Pemangkasan minggu ke 8 menunjukkan hasil paling optimal dalam peubah umur berbunga, jumlah tandan bunga, jumlah bunga, jumlah polong, bobot kering polong, dan bobot biji. Pemangkasan pada minggu ke 10 menunjukkan hasil paling optimal dalam peubah jumlah daun, bobot 100 biji, dan indeks panen. Varietas KT-8 menunjukkan hasil paling optimal pada peubah jumlah daun, jumlah tandan bunga, jumlah bunga, jumlah polong, bobot kering polong, bobot biji, dan indeks panen, Leaves pruning is one of the efforts that can be done to increase the productivity of cowpea. The experiment aimed to determine the best time to prune the leaves in obtaining the most optimal productivity. The experiment was conducted at Tangkil Village, Citeureup, Bogor, from April to July 2017. The experiment was arranged in split plot randomized block design with four replications and two factors. The main plot was variety of cowpea consisted of KT-2, KT-6, and KT-8. The subplot was pruning time consisted of 4 MST, 6 MST, 8 MST, and 10 MST. The result showed that leaf pruning significantly affected the increase of number of pods, weight of dry pods, and weight of cowpea grains. The most optimal yield component was obtained in plants with old pruning treatment (8 MST and 10 MST). Pruning at week 8 showed the most optimal result in the variables of flowering age, number of flower bunches, number of flowers, number of pods, weight of dry pods, and weight of grains. Pruning at week 10 showed the most optimal results in variables of number of leaves, weight of 100 grains, and harvest index. KT-8 showed the most optimal results on the variable number of leaves, number of flower bunches, number of flowers, number of pods, weight of dry pods, weight of grains, and harvest index.
Keyword: harvest index, KT-8, pruning time, sink source, southern pea

Judul: The Effect of Type and Pruning Time for Peanuts (Arachis hypogaea) Production of Zebra Varieties
Abstrak: Hasil produksi kacang tanah dapat ditingkatkan dengan cara melakukan pemangkasan pada cabang tanaman. Pemangkasan pada cabang diharapkan dapat menekan laju pertumbuhan vegetatif sehingga laju pertumbuhan generatif meningkat. Penelitian ini bertujuan mengetahui jenis pangkas dan waktu pangkas yang berpengaruh terhadap hasil produksi kacang tanah. Penelitian ini dilaksanakan di Kebun Percobaan Leuwikopo IPB pada bulan November 2020 sampai Maret 2021. Rancangan percobaan yang digunakan dalam penelitian ini adalah rancangan petak terbagi (split-plot) dengan petak utama merupakan jenis pangkas dan anak petak merupakan waktu pangkas. Jenis pangkas yang digunakan adalah tanpa pangkas, pangkas batang utama, dan pangkas cabang lateral. Waktu pangkas adalah pada saat tanaman berumur 6 MST, 8 MST, dan 10 MST. Hasil penelitian menunjukkan jenis pangkas berpengaruh nyata terhadap jumlah cabang lateral pada 8 MST, 10 MST, dan 12 MST. Jenis pangkas juga berpengaruh nyata terhadap bobot 100 biji. Waktu pangkas tidak memberikan pengaruh yang nyata terhadap peubah pengamatan yang diamati. Interaksi antar kedua perlakuan berpengaruh nyata terhadap bobot 100 biji., Peanuts production can be increased by pruning plant branches. Pruning is expected can be suppressed the vegetative growth rate so that the generative growth rate increases. The purpose of this research is to find out which type and time pruning that can affect peanuts production. This research was conducted in Leuwikopo Experimental Station IPB on November 2020 until March 2021. This research is arranged in split-plot randomized block design with the main plot is the type of pruning and the subplot is time of pruning. The types of pruning are without pruning, main branches pruning, and lateral branches pruning. Time of pruning is when the age of the plant are 6 weeks after planting, 8 weeks after planting, and 10 weeks after planting. The result shows that type of pruning affects the number of lateral branches at week 8, week 10, and week 12. Type of pruning also affects weight of 100 seeds. Time of pruning does not have significant effect on the observed variables. Interaction between the two treatments affect the weight of 100 seeds.
Keyword: generative growth rate, peanuts, productivity, type of pruning

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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