Judul: Synchronization of Nitrogen supply from green manures and urea with corn growth in Inceptisol Darmaga
Abstrak: Increasing N use efficiency and decreasing N pollution were archieved by sybchronization between supplying pattern of N and crop N demand. Leaching-incubation experiment was carried out for evaluating supplying pattern of N from 14 treatments of green manures (Flemingia and Gliricidia), Urea and their combination, and single application of combination of urea and Gliricidia synchronize with the model of corn N uptake.
Keyword: leaching-incubation, supplying pattern of N, model of corn N uptake, fertilization treatment, West Java

Judul: Comparison of nitrogen absorption by corn (Zea mays L.) from four urea fertilizers
Abstrak: Jagung merupakan salah satu komoditas pangan utama di Indonesia. Peningkatan produktivitas jagung umumnya menggunakan pupuk urea untuk memenuhi kebutuhan nitrogennya. Masalah utama terkait penggunaan urea yaitu tingginya jumlah nitrogen tercuci. Salah satu upaya mencegah pencucian N yaitu dengan mengubah senyawa urea menjadi senyawa urea lambat tersedia (slow release), diantaranya dengan mengubah sebagian senyawa urea menjadi urea-formaldehida yang bersifat lambat tersedia. Penelitian ini bertujuan untuk mempelajari pengaruh empat jenis pupuk urea terhadap bobot biomassa kering, serapan nitrogen, dan efisiensi serapan nitrogen. Penelitian menggunakan rancangan acak lengkap satu perlakuan dengan empat ulangan. Penelitian dilaksanakan di rumah kaca dengan media tanah seberat 15 kg (Bobot Kering Mutlak) dengan polybag. Perlakuan terdiri atas perlakuan tanpa pemupukan N (kontrol), pemupukan urea konvensional yang terdiri dari urea kujang dan urea pusri dan urea slow-release berupa urea urea granul (0,5% formaldehida) dan urea prill (0,1% formaldehida). Biomassa bagian atas tanaman untuk keperluan analisis dipanen tiap minggu selama 10 minggu dari satuan percobaan yang terpisah. Analisis kadar N jaringan jagung dilakukan setiap minggu panen dengan metode mikro Kjehdahl. Hasil percobaan menunjukkan pemberian urea slow-release, khususnya urea granul, meningkatkan bobot biomassa jagung dibandingkan dengan penggunaan urea konvensional. Selain itu, penggunaan urea slow-release memiliki tingkat efisiensi lebih tinggi dibandingkan dengan urea konvensional. Faktor yang menyebabkan urea granul memiliki serapan dan efisiensi yang lebih tinggi adalah pelapisan butir dengan senyawa urea-formaldehid pada urea slow-release., Corn is one of the main foods commodities in Indonesia. To increase corn productivity, urea fertilizer is commonly used to supply its nitrogen (N) needs. The main problem related to the use of urea fertilizer is the high amount of nitrogen leached. One way to prevent nitrogen leaching is by forming a urea compound to a slow-release compound, one of them is changing part of the urea compound to urea-formaldehyde. This research was aimed to study the effect of four different urea fertilizers on corn’s biomass production, nitrogen absorption, and nitrogen absorption efficiency. This research used a completely randomized design of one factor with four repetitions. The research was carried out in a greenhouse with 15 kg soil as plant’s media in a polybag. The treatments consisted of treatment without N fertilization (control), conventional urea fertilizers (kujang urea and pusri urea), and slow-release ureas which is granule urea (0.5% formaldehyde) and prill urea (0.1% formaldehyde). Upper plant biomass for analysis was harvested every week for 10 weeks from separated experimental uni. Total N analysis was determined by mikro Kjeldahl method. The result showed that the application of slow-release urea, especially granulated urea, increased nitrogen absorption and biomass weight compared to the application of conventional urea fertilizers. Factors that cause the granule slow-release urea has higher absorption and efficiency is the coating of the grain with urea-formaldehyde
Keyword: conventional urea, granulated urea, nitrogen efficiency, slow-release, urea-formaldehyde

Judul: Pola Pewarisan Karakter Suara Kicauan Pada Burung Perkutut
Abstrak: Turtledove (Geopelia striata) is a singing birds that has a better melodious voice. The inheritance of this character has not been determined, so that research on the voice inheritance is important. This study was aimed to characterize the voice patterns turtledove. Materials consisted of 12 pairs of parents and their progenies. Twelve of their turtledove was ranked based on their sound quality. The parameters observed included voice patterns, the presence of elements of sound, the type of sound, harmonious sound (frequency and level of sound intensity) and duration of the total sound. Voice analysis was done by using computer software Cool Edit Pro version 2.1. Sound visualization was displayed in waveform shape. Sound intensity level was determined using the formula TI = 10 log I/I0, with the value I0 at 10-12 W/m2. Based on the inheritance analysis sire voices is a better chance in herediting of the voice and the number of beats sound of the middle voice. Dam plays an role in giving voice rhythm modification and sound tip inheritance. Based on the sound analysis, sound quality the voice rank from the highest to the lowest were: ♂AK, ♂ FQ, ♂HHa, ♂ ISS, ♂HRR, ♂ BL, ♂CM, ♂ EQ, ♂GQ, ♂DO, ♂DN, and ♂DP. The frequency value and the highest intensity level displayed by AK turtledove were 929.49 Hz and 91.5 dB, whereas the lowest value displayed by ♂DP were 633.59 Hz, and 67.83 dB. The best rhythm of the turtledove indicated by high frequency with a stable pattern, harmonious the intonation, as well as clear basic voice.
Keyword: