Judul: Respon Sorghum bicolor (Linn.) terhadap Perbaikan Tanah Masam PT Holcim Tbk, Cibadak, Kabupaten Sukabumi
Abstrak: Mining activities have some obstacles such as acid soil where soil pH is low, high Al saturation, less of macro nutrients content, especially P, K, Ca, and Mg, and low organic content. The purpose of this research was to determine the right treatment of acid soil reparation in the post-mining land and see the impact of acid soils reparation in Sorghum bicolor plants. The research consisted of two factors, namely the treatment of medium acid soil (soil color is gray, reddish brown, brown) and the HSC (Humate Substance Complex) treatment in concentration 1L: 400L, 1L: 800L, and without HSC (control). The appropriate treatment for grey and brown acid soil reparation is adding HSC with a concentration of 1L: 800L, while reddish brown soil with a concentration of 1L:400L. The reparation acid soil with HSC has some impacts on the performance improvement such as increased root length, apical root length, quantity of lateral roots, and lateral root length and leaf color.
Keyword: toxicity, Sorghum bicolor, HSC, acid soil

Judul: The Effect of Acid soil Applied with Earthworm Eisenia foetida on Growth, Biomass Production, and Quality of Sorghum bicolor
Abstrak: Penelitian ini menggunakan tanah masam pasca aplikasi cacing tanah. Tujuan penelitian ini adalah pengaruh penggunaan tanah masam aplikasi cacing tanah Eisenia foetida terhadap pertumbuhan, produksi biomassa, dan kualitas Sorghum bicolor. Penelitian ini menggunakan rancangan acak lengkap faktorial dengan 3 kali ulangan. Faktor pertama adalah media bekas cacing (0 dan 60 ekor). Faktor kedua adalah tanah masam (podsolik dan latosol). Data di analisis menggunakan ANOVA dengan program SPSS versi 20. Parameter yang diamati adalah tinggi tanaman, jumlah daun, analisis produktivitas, analisis kandungan nutrien, serta pH tanah. Hasil penelitian ini perlakuan media bekas cacing dan jenis tanah masam podsolik dan latosol tidak memberikan pengaruh negatif terhadap pertumbuhan, produksi biomassa, dan kualitas tanaman Sorghum bicolor., This study used acid soil that had been applied with earthworm. This study aimed the effect of acid soils that had been applied with earthworm (Eisenia foetida) on growth, biomass production, and Sorghum bicolor quality. This study used factorial completely randomized design with 3 replicates. The first factor was organic residue of earthworm level (0 and 60 earthworms, respectively) the second factor was the type of acid soil (latosol and red yellow podsolik). The data were analyzed with analysis of variance using by SPSS 20. The parameters observed were plant lenght, number of leaves, productivity analysis of sorghum, nitrogen, phosporus, potassium of the plant and soil pH. The results of this study showed growth, biomass production, and quality of sorghum increased by planting on earthworm 60 media and red yellow podsolic soil type.
Keyword: E. foetida, latosol soil, red yellow podsolic soil, S. bicolor

Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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