Judul: Potential of Forage Under the Shade of Sorghum with Different Levels of Urea Fertilizer and Quality as a Silage Product
Abstrak: Penelitian bertujuan mengetahui potensi hijauan pakan di bawah naungan tanaman sorgum (Sorghum bicolor (L.) Moench) dengan level pupuk urea berbeda dan kualitasnya sebagai produk silase. Metode yang digunakan adalah observasi lapang langsung terhadap tumbuhan di bawah tanaman sorgum dengan perbedaan pemberian pupuk urea. Rancangan percobaan yang digunakan merupakan Rancangan acak lengkap (RAL) pada 3 perlakuan lahan dengan 4 ulangan, dan dilanjutkan dengan uji jarak Duncan jika terdapat perbedaan yang nyata. Parameter yang diukur meliputi intensitas cahaya, tingkat naungan, suhu, kelembaban, pH tanah, tekstur tanah, biomassa hijauan, kapasitas tampung, analisis vegetasi serta analisis karakteristik fisik dan palatabilitas silase. Hasil penelitian menunjukkan perbedaan level pupuk urea di bawah tanaman sorgum berpengaruh nyata (p<0,01) pada parameter intensitas cahaya, tingkat naungan dan kelembaban akan tetapi tidak berpengaruh nyata terhadap suhu, biomassa, dan kapasitas tampung hijauan. Potensi hijauan pakan yang berada di bawah tanaman sorgum dengan level pupuk urea berbeda menunjukkan keanekaragaman hijauan sedang dengan kemerataan jenis yang tinggi. Jenis hijauan Echinochloa colonum (L.) Link., Cleome rutidosperma DC., dan Spermacoce alata Aubl. memiliki indeks nilai penting yang tinggi pada setiap perlakuan. Produk silase asal rumbah dihasilkan aroma dan warna yang baik dengan skor 3 dengan tingkat palatabilitas kurang disukai dengan skor 2 (skala 1-4)., Research has been carried out on the potential for forage under the shade of sorghum (Sorghum bicolor (L.) Moench) with different levels of urea fertilizer and its quality as a silage product. The method used is direct field observation of plants under sorghum with differences in the application of urea fertilizer. The experiment used was a completely randomized design (CRD) on 3 fields with 4 replications, and continued with Duncan's distance test if there were significant differences. The observed parameters were divided into light intensity, shade level, temperature, humidity, soil pH, soil texture, forage biomass, storage capacity, vegetation analysis, analysis of the physical characteristics and palatability of silage. The results showed that the difference in urea fertilizer levels under sorghum had a significant effect (p<0.01) on the parameters of light intensity, shade level and humidity but had no significant effect on temperature, biomass, and forage holding capacity. Forage potential under sorghum with different levels of urea fertilizer shows moderate forage diversity with high evenness of species. Forage species Echinochloa colonum (L.) Link., Cleome rutidosperma DC., and Spermacoce alata Aubl. had a high index of significance in each treatment. Silage product from rumbah produces good aroma and colour with a score of 3 with a less favorable palatability level with a score of 2 (scale 1-4).
Keyword: Forage, Silage, Sorghum shade, Urea fertilizer

Judul: Determination of Physiological Maturity of Sorghum Seeds (Sorghum bicolor L. Moench) with Two Doses of NPK Fertilizer
Abstrak: Pemupukan dengan dosis yang tepat akan meningkatkan produksi dan mutu benih sorgum. Umur panen yang tepat juga dapat mempengaruhi mutu benih yang dihasilkan. Penelitian bertujuan untuk menentukan masak fisiologis benih sorgum (Sorghum bicolor L. Moench) pada dua dosis pemupukan NPK. Penelitian ini menggunakan Rancangan Split Plot dengan Rancangan Acak Lengkap (RAL). Petak utama adalah dosis pupuk NPK dan anak petak adalah tingkat kemasakan benih setelah antesis. Dosis pupuk pertama yang digunakan yaitu urea 150 kg ha-1 , SP-36 100 kg ha-1 , dan KCl 100 kg ha-1. Dosis pupuk kedua yang digunakan yaitu urea 225 kg ha-1, SP-36 175 kg ha-1, dan KCl 175 kg ha-1. Tingkat kemasakan yang digunakan yaitu 25, 30, 35, 40 hari setelah antesis (HSA). Perlakuan diulang sebanyak tiga kali sehingga diperoleh 24 satuan percobaan. Hasil penelitian menunjukkan bahwa pengaruh faktor tingkat kemasakan menunjukkan hasil yang berpengaruh sangat nyata pada tolok ukur kadar air, bobot 1000 butir, laju pertumbuhan kecambah, sedangkan kecepatan tumbuh benih mendapatkan hasil yang berpengaruh nyata. Pengaruh interaksi dosis pupuk NPK dan tingkat kemasakan benih sangat nyata terhadap pada tolok ukur bobot kering kecambah normal. Masak fisiologis benih sorgum diperoleh pada 35 hari setelah antesis dengan dosis pupuk urea 150 kg ha-1, SP-36 100 kg ha-1, dan KCl 100 kg ha-1 ., The fertilizer with the right doses will improve the results of production and quality of the sorgum seed. The physiological maturity characterized by a quality seed that has reached the maximum seed dry weight, viability and vigor. The aim of research is to determine the physiological maturity of the seed sorghum (Sorghum bicolor L. Moench) at two doses of NPK fertilizer. The experiment was arranged in Split Plot Design with Completely Randomized Design (CRD). The main plot is dose of fertilizer and the sub plot is the level of maturity. The first dose is 15 kg ha-1 of urea, 100 kg ha-1 of SP-36, and 100 kg ha-1 of KCl. The second dose is 225 kg ha-1 of urea, 175 kg ha-1 of SP-36, and 175 kg ha-1 of KCl. The maturity level will harvest at 25, 30, 35, 40 days after anthesis (DAS). The treatment was repeated three times to obtain 24 experimental units. The results showed that the influence of the maturity level had a highly significant effect on the moisture content, 1000 grain weight, growth rate, had a significant effect to speed of germination. The interaction effect of NPK fertilizer dose and seed maturity level showed results had a highly significant effect to the standard dry weight of normal seedling. The physiological maturity of sorghum seeds is harvest at maturity level of 35 DSA with a doses of 150 kg ha-1 of urea, 100 kg ha-1 of SP-36, 100 kg ha-1 of KCl.
Keyword: fertilizer, level of maturity, production, seed quality, sorgum

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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