Judul: Soil Physical Properties and Infiltration Rate at  Various Density Levels in The Urban Forest Park of Muhammad Sabki, Jambi
Abstrak: Taman Hutan Kota Muhammad Sabki merupakan salah satu ruang terbuka hijau yang ada di Kota Jambi. Salah satu fungsi taman hutan kota adalah sebagai sumber air bagi masyarakat kota. Sifat fisika tanah merupakan unsur lingkungan yang sangat berpengaruh terhadap tersedianya air, udara tanah dan secara tidak langsung mempengaruhi ketersediaan unsur hara tanaman. Tujuan dilakukan penelitian ini adalah untuk menganalisis sifat fisik tanah dan menghitung laju infiltrasi pada kerapatan tajuk yang berbeda. Kerapatan tajuk diukur menggunakan spherical densiometer (SD) kemudian sampel tanah diambil pada tiga titik dengan plot berukuran 20m × 20m pada setiap kerapatan tajuk. Sampel tanah kemudian dianalisis tekstur, bobot isi, porositas, dan kadar air. Laju infiltrasi diukur menggunakan double ring infiltrometer dengan melihat besar penurunan air pada ring bagian dalam melalui mistar hingga konstan, kemudian data juga diolah menggunakan model rumus Horton. Berdasarkan hasil penelitian, tekstur tanah yang dominan berupa lempung, bobot isi tanah tergolong sedang, kadar air pada kerapatan tajuk rapat, cukup, dan jarang berturut-turut sebesar 20,37%, 25,33%, dan 29,27%, porositas tergolong porous sampai dengan baik dan kelas infiltrasi tanah tergolong sangat cepat. Hubungan antara tingkat kerapatan tajuk dan sifat fisik tanah memiliki korelasi positif signifikan pada infiltrasi tanah dan negatif signifikan pada kadar air tanah., Urban forests have an important role in maintaining the hydrological cycle. The hydrological cycle is important in relation to the provision of water in the soil. Muhammad Sabki Urban Forest Park is one of the green open spaces in Jambi City, One of the functions of the urban forest park is as a source of water for the city community. The physical properties of soil are environmental elements that greatly affect the availability of water and soil air and indirectly affect the availability of plant nutrients. The purpose of this research is to analyze the physical properties of the soil and calculate the infiltration rate at different canopy densities. Canopy density was measured using a spherical densiometer (SD) then soil samples are taken at three points with a plot measuring 20m × 20m at each canopy density. Soil samples are then analyzed for texture, bulk density, porosity, and moisture content. The infiltration rate is measured using a double ring infiltrometer by looking at the amount of water decrease in the inner ring through the ruler until it is constant, then the data is also processed using the Horton formula model. Based on the results of the study, the dominant soil texture in the form of clay, the weight of the soil is classified as moderate, the moisture content of the canopy density are 20,37%, 25,33%, and 29,27%, the porosity is classified as porous to good and the class of soil infiltration is very fast. The relationship between the level of canopy density and the physical properties of the soil has a significant positive correlation with soil infiltration and a significant negative correlation with soil water content.
Keyword: bulk density, infiltration, water content, porosity, texture

Judul: Effect of Vegetation Density and Soil Physical Characteristics on Infiltration Rate in the Jasinga Silviculture Teaching Industry (JSTI) Area
Abstrak: Hutan Jasinga Silviculture Teaching Industry (JSTI) termasuk hutan penelitian dengan kondisi ekosistem yang belum banyak diketahui. Dibutuhkan penelitian pada ekosistem setempat terutama terkait vegetasi, tanah, dan siklus hidrologi. Tutupan lahan vegetasi di Hutan JSTI belum merata yang memengaruhi resapan air tanah (laju infiltrasi). Penelitian ini bertujuan mengidentifikasi komposisi vegetasi dan sifat fisik tanah yang memengaruhi laju infiltrasi. Plot ditentukan melalui teknik purposive sampling berdasarkan kerapatan vegetasi. Komposisi vegetasi diketahui berdasarkan indeks nilai penting (INP). Laju infiltrasi diukur menggunakan double-ring infiltrometer. Hasil penelitian menunjukkan bahwa komposisi vegetasi bervariasi sesuai dengan tingkat kerapatan tajuk. Struktur tanah berupa subangular blocky dengan tekstur liat, kadar bahan organik tergolong tinggi (>4%), bulk density tergolong sedang, porositas yang didominasi kategori porous, serta kadar air dan laju infiltrasi plot vegetasi rapat cenderung lebih besar dibandingkan plot vegetasi jarang. Parameter kerapatan vegetasi dan sifat fisik tanah yang dianalisis memiliki pengaruh yang kuat hingga sangat kuat dengan laju infiltrasi tanah., The Jasinga Silviculture Teaching Industry (JSTI) forest is a research forest with ecosystem conditions that have yet to be widely known. Research on the local ecosystem is needed, especially regarding vegetation, soil, and the hydrological cycle. Vegetation land cover in the JSTI Forest is uneven, which affects groundwater absorption (infiltration rate). This study aims to identify the vegetation composition and soil physical properties that affect the infiltration rate. Plots were determined through a purposive sampling technique based on stand density. Vegetation composition is known based on the important value index (IVI). The infiltration rate was measured using a double-ring infiltrometer. The results showed that the composition of the vegetation varies according to the level of crown density. The soil structure is subangular blocky with a clay texture, the organic matter content is high (> 4%), the bulk density is moderate, the porous category dominates the porosity, the water content and infiltration rate of dense vegetation plots was more excellent than sparse vegetation plots. Vegetation density parameters and soil physical properties analyzed have a strong to very strong relations with soil infiltration rate.
Keyword: erosion, vegetation density, groundwater infiltration

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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