Judul: Pengaruh Pemberian Biosoil terhadap Sifat Kimia  Tanah serta Pertumbuhan dan Produksi Tanaman  Caisim (Brassica chinensis)
Abstrak: Several methods are able to increase soil productivity. One of them is biosoil (a soil conditioner with contains 8 % of humic acid extracted from leonardite). Biosoil plays important role in improving physical, chemical and biological properties of soil. The application of the substance increases soil fertility thus increases fertilization efficiency. Greenhouse experiment was conducted using Latosol from Darmaga. The aim of this research was to evaluate effect of biosoil on chemical properties of soil as well as the growth and yield of caisim (Brassica chinensis). The experiment consisted of 5 treatments and 3 replications, and was arranged in completely randomized design. The treatments applied biosoil 0, 25, 50, 70, 100 l/ha which equivalent to 0, 0.06, 0.13, 0.19, 0.25 ml/pot. Fertilizers applied were 500 mg/pot urea, 375 mg/pot SP36 and 250 mg/pot KCl. The result of experiment indicated that the effects of biosoil on available P and K and soil pH and CEC were not significant. On the other hand, the effect of biosoil on exchangeable Al was significant. Increasing exchangeable Al and low soil pH after application of biosoil caused caisim did not respond to biosoil application. Increasing dosage of biosoil tended to decrease wet and dry bweight of plant. In addition, the effect of biosoil on P and K contents of plant were not significant,while on N content was significant.
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Judul: Pengaruh Zeolit Dan Biosoil Pada Sifat Kimia Tanah Dan Produksi Tanaman Caisim Bangkok (Tosakan).
Abstrak: Several methods are able to increase soil and crop productivity. Zeolith and biosoil application are one of methods to enhance plant growth and yield. The aim of this research was to evaluate effect of zeolith and biosoil to chemical characteristic of soil (pH, cation exchange capacity, exchangeable cation, NO3 - and NH4 +) and yield of Caisim Bangkok (Tosakan) in Regosol Ciomas Bogor. This research was layout by randomize complete design with two factor. The first factor was 5 level of zeolith: 0 ton/ha, 7.5 ton/ha, 15 ton/ha, 22.5 ton/ha, dan 30 ton/ha. The second factor was 2 level of biosoil : 0 l/ ha dan 20 l/ha, with 3 replications. This research conducted with two steps. The first step was incubation research and the second step was green house research. This research shows that application of zeolith significantly increased Na-dd and cation exchange capacity (KTK) in the rate of Z4 and tend to increase exchangeable Ca and Mg, and to decrease exchangeable K and to increase soil base saturation (KB). Biosoil application tend to decrease exchangeable Ca and Mg, but tend to increase exchangeable K and Na, cation exchange capacity (KTK) and soil base saturation (KB). However, zeolith and biosoil application, tend to decrease NO3 and NH4 ions. Zeolith application tend to decrease wet and dry weight leaves and root of caisim, whereas biosoil tend to increase wet and dry weight of the leaves, but significantly decreased wet weight of the root and tend to decrease dry weight of root. Zeolit significantly decreased N concentration and N uptake, and tend to decrease P and K contain and uptake of P and K whereas biosoil tend to increase N, P and K concentration and N, P and K uptake.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular