Judul: Pengelolaan hayati tanah untuk meningkatkan peran fauna tanah dalam proses dekomposisi jerami padi pada budidaya System of Rice Intensification (SRI) di Kecamatan Cibungbulang, Kabupaten Bogor
Abstrak: Recently, low agricultural production is becoming a main problem in agricultural sector in Indonesia, especially for food crop. System of Rice Intensification (S.R.I.) is a method of rice cultivation which is able to increase crop yield through soil, crop and water management system. The principles of the S.R.I. technique include planting of young and single seedlings with shallow-root planting, wide spacing and maintain unflooded soil condition with intermittent irrigation. Soil biological management can be applied to support the creating of more conducive environment for improving population and role of soil fauna, especially on organic matter decomposition. Modification of bund distance in rice field is one of those methods. This research aimed to study the effect of bund distance (4 meters and 8 meters) on the role of soil fauna in rice straw decomposition in S.R.I. cultivation technique by using litterbag method. The research was conducted in NOSC (Nagrak Organic S.R.I. Center) field in Cijujung Village, Cibungbulang Subdistrict, Bogor Regency. This research was designed according to bund distance treatment, two levels (short, 4 meters and long, 8 meters) and four replications. Measurement of the decomposition rate of rice straw performed by using litterbag in coarse mesh (10 mm), medium mesh (0.25 mm) and fine mesh (0.038 mm), which contained 10 g rice straw per litterbag. These litterbags were exposured to the rice field with humid soil condition and retrieved after 30, 60 and 90 days. Decomposition rate was measured by counting the difference weight of before and after exposure time. The result showed that decomposition rate of the rice straw in the field with short bund distance (4 meters) is higher than in the field with long bund distance (8 meters). Decomposition rate based on the difference of litterbag showed that in field with short bund distance, coarse mesh litterbag have the higher rate with 93.91%, meanwhile medium mesh size about 89.07% and fine mesh about 81.58%. In long bund distance field, percentage of coarse -, medium - and fine mesh sizes are 88.98%; 85.87% and 78.53%, respectively. This result showed that the field with short bund distance have the higher decomposition rate, indicated that field with short bund distance has more soil fauna population that involved in decomposition process, compared to field with long bund distance.
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Judul: Peningkatan populasi dan keragaman fauna tanah melalui pengelolaan hayati tanah pada budidaya System of Rice Intensification (S.R.I.) di Kecamatan Cibungbulang, Kabupaten Bogor
Abstrak: Soil fauna is important component in the soil ecosystem. They play a very important role in organic matter decomposition, nutrient cycling, nutrient availability and uptake, soil physical properties, prevention of nutrient leaching, and maintain plant health through natural predation and parasitism of plant pathogens and pest. Land management practice can affect soil fauna population and diversity, therefore land management should be environmental frindly, in order to preserve the ecosystem and consequently improve diversity of the soil fauna. In the rice field ecosystem, modification of bund distance is one of managements to improve population and diversity of soil fauna. This research aimed to evaluate the effect of different bund distance (4m and 8m) on soil fauna population and diversity in System of Rice Intensification (S.R.I.). S.R.I. is an innovative cultivation technique to increase yields. The basic principles of S.R.I. method are the use of young seedling of 8-12 days old, wide spacing of 30 cm x 30 cm, maintain unflooded soil condition and planting with a single seed. The research was conducted in Cibungbulang sub district of Bogor regency and Laboratory of Soil Biotechnology of Soil Science and Land Resource Department, Bogor Agricultural University. The research used a treatment of bund distance with two levels (4m and 8m) and four replications. The result showed that the abundance and biomass of soil fauna in plot with 4m bund distance (4m plots) were 26259 individual/m2 and 11.7 g/m2, respectively, and plot with 8m bund distance (8m plots) were 8402 individual/m2 and 2.3 g/m2, respectively. Abundance and biomass of soil fauna in 4m bunds were 25343 individu/m2 dan 10.8 g/m2, respectively, meanwhile in 8m bunds were 19611 individu/m2 and 6.4 g/m2, respectively. The cultivation of soybean in the bund was proven to be able to increase soil fauna population in the bund, that can be seen from 0 day to 90th days. Diversity Index calculated according to Shannon Diversity Index showed the low value (< 1.5) in both 4m plots and 8m plots. The most dominant animals in 4m and 8m plots was Collembola, meanwhile in the bunds was Hymenoptera. The rice productivity determined by the parameters of yield (ton/Ha), filled and empty grain percentage (%), and weight of 1000 grains (g) showed a higher value in 4m plots, as compared to 8m plots. The results in 4m plots based on parameters above were 5.08 ton/ha, 82.64 % 17.36 % and 26.87 g, respectively, meanwhile in 8m plots were 4.96 ton/ha, 76.39 %, 23.61 % and 26.29 g, respectively.
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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