Judul: Pengaruh asam humat dan cara pemberiannya terhadap pertumbuhan dan produktivitas tanaman padi (Oryza sativa)
Abstrak: Agricultural land in Indonesia degraded continuously, characterized by decreasing in soil organic matter resulting from the utilization of chemical fertilizers which is not followed by organic fertilizers. In the rice field, the decrease of organic matter is followed by soil compacting and the decrease in soil pH. In order to increase paddy production, it is needed to improve the soil qualities plants growth. This can be achieved by providing ameliorants such as organic matter with chemical fertilizers. But there is a problem in applying organic matter because of its huge volume. Therefore, it is necessary to find a way to replace the organic matter with other materials that are easier not only in procurement but also in application. Humic acid is an extract of organic material which is expected to be able to replace the role of organic matter in improving physical, chemical, and biological properties of soils. Humic acid is expected to be able for improve plant growth through its role in accelerating the absorption of soil nutrients and water. The research was conducted in a greenhouse located at Cikabayan, Bogor Agricultural University with paddy var. Ciherang as the indicator plant. Soil was taken from Situ Gede, Bogor. Basal fertilizers were 300 kg/Ha SP-18, 200 kg/Ha KCl, and 200 kg/Ha urea. Humic acid dosages used were 0 L/Ha, 5 L/Ha, 10 L/Ha and 15 L/Ha. The methods of humic acid application were spraying on the surface of leaves, spraying underside of leaves, and spraying on the soil. The result showed that humic acid can increase the growth of rice plants by increasing tiller number. Humic acid dosage of 15 L/Ha spraying on the soil is the best treatment indicated by tiller number and dry weight of unhulled rice.
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Judul: The Effect of ZeomicAgro Soil Ameliorant on the Productivity of Rice on Sawah Baru Experimental Field Dramaga
Abstrak: Perbaikan kesuburan tanah dan peningkatan efisiensi penggunaan pupuk anorganik penting diupayakan dalam meningkatkan produktivitas pertanian, antara lain dengan penambahan bahan pembenah tanah. Salah satu pembenah tanah adalah ZeomicAgro yang berbahan dasar zeolit, bahan humat, dan kapur. Tujuan dari penelitian ini untuk mengetahui pengaruh pemberian ZeomicAgro terhadap sifat kimia tanah, pertumbuhan dan produktivitas padi. Penelitian dilakukan di Kebun Percobaan Sawah Baru, dengan jenis tanah Latosol, dan menggunakan benih padi IPB 3S. Penelitian dilakukan menggunakan rancangan acak lengkap (RAL) non faktorial dengan lima perlakuan dan empat ulangan. Perlakuan merupakan kombinasi dosis ZeomicAgro dan pemupukan, dengan P1 (kontrol, tanpa ZeomicAgro dan tanpa pupuk), P2 (pemupukan standar, tanpa ZeomicAgro, Urea 200 kg/ha, SP-36 100 kg/ha, dan KCl 100 kg/ha), P3 (ZeomicAgro 100 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, dan KCl 75 kg/ha), P4 (ZeomicAgro 200 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, dan KCl 75 kg/ha), P5 (ZeomicAgro 300 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, dan KCl 75 kg/ha). Hasil penelitian menunjukkan bahwa perlakuan ZeomicAgro dosis 200 kg/ha nyata meningkatkan kadar Corganik, NO3 - , P-tersedia dan K-dd, serta cenderung meningkatkan N-total dan KTK. Pemberian ZeomicAgro berpengaruh nyata terhadap tinggi tanaman dan jumlah anakan pada umur tanaman 9 MST, serta meningkatkan jumlah anakan produktif. Perlakuan ZeomicAgro dengan dosis 200 kg/ha dapat mengurangi dosis pemupukan urea hingga 50 %, pupuk SP36 dan KCl hingga 25%, dengan tingkat produktivitas tidak berbeda nyata dengan perlakuan standar., Improving soil fertility and increasing the efficiency of using inorganic fertilizers are important efforts to increase agricultural productivity, including by adding soil ameliorant. One soil ameliorant is ZeomicAgro which is made from zeolite, humic substance and lime. The aim of this research is to determine the effect of ZeomicAgro on the growth and productivity of rice. The research was carried out at the Sawah Baru, IPB Experimental Field, with Latosols soil type, and using IPB 3S rice seeds. The research was conducted using a non-factorial completely randomized design (CRD) with five treatments and four replications. The treatment was a combination of ZeomicAgro doses and fertilization, with P1 (as a control, without ZeomicAgro and fertilizer), P2 (standard fertilization, without ZeomicAgro, Urea 200 kg/ha, SP-36 100 kg/ha, and KCl 100 kg/ha), P3 (ZeomicAgro 100 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, and KCl 75 kg/ha), P4 (ZeomicAgro 200 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ ha, and KCl 75 kg/ha), P5 (ZeomicAgro 300 kg/ha, Urea 100 kg/ha, SP-36 75 kg/ha, and KCl 75 kg/ha). The results showed that ZeomicAgro treatment with a dose of 200 kg/ha (P4) significantly increased levels of organic-C, NO3 - , available-P and exchangeable-K, and tended to increase totalN and CEC. The application of ZeomicAgro had a significant effect on plant height and number of tillers at 9 WAP, as well as increasing the number of productive tillers. ZeomicAgro treatment with a dose of 200 kg/ha can reduce the doses of urea fertilizer by up to 50%, SP36 and KCl fertilizer by up to 25%, with productivity levels not significantly different from standard treatment.
Keyword: Bahan Humat, Efisiensi pemupukan, latosol, Zeolit, IPB 3S, Fertilizer efficiency, humic substance, IPB 3S, Latosols, zeolite

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf