Judul: Weed Control Management of Tea (Cammellia sinensis (L.) Kuntze) Plantation at PT Perkebunan Nusantara XII, Malang, East Java
Abstrak: Gulma merupakan tumbuhan yang kehadirannya dapat mengganggu pertumbuhan tanaman, sebab gulma dapat menurunkan hasil produksi tanaman. Pengendalian gulmaperlu dilakukan agar kerugian yang diakibatkan oleh gulma bisa diatasi. Kegiatan magang bertujuan memahami dan mempelajari pengelolaan pengendalian gulma serta menganalisis aspek pengendalian gulma yang dilakukan di kebun. Hasil pengamatan menunjukan pengendalian gulma di Afdeling Wonosari dilakukan secara manual dan kimiawi. Pengendalian gulma manual dilakukan untuk mengendalikan gulma diatas bidang petik, gulma yang tingginya >30 cm, serta gulma berkayu. Pengendalian kimiawi dilakukan dengan alat knapsack sprayer dan herbisida yang digunakan berupa herbisida sistemikdengan bahan aktif Isopropilamina Glyphosat. Pengendalian gulma secara kimiawi lebih efektif dan efisien dari sisi tenaga kerja, biaya, serta hasil luasan yang dikerjakan. Kalibrasi semprot dilakukan sebelum dilakukan penyemprotan untuk mengetahui volume semprot yang diperlukan agar penyemprotan dapat dilakukan secara efektif. Keefektifan penyemprotan herbisida dipengaruhi oleh waktu pengaplikasian, waktu turunnya hujan,serta kemampuan penyemprot., Weeds are plants that can interfere with plant growth, because weed can reduce crop production. Weed control needs to be done so that the losses caused by weeds can be overcome. The internship activity aims to under standard study weed control management and analyze aspects of weed control carried out in the garden. Observations showed that weed control in Afdeling Wonosari was carried out manually and chemically. Manual weed control was carried out to control weeds above the picking field, weeds >30 cm high, and woody weeds. Chemical control is carried out by means of a knapsack sprayer and the herbicide used is a systemic herbicide with the active ingredient Isopropylamine Glyphosate. Chemical weed control is more effective and efficient in terms of labor, costs,and the results of the area worked. Spray calibration is carried out before spraying to determine the volume of spray required so that spraying can be carried out effectively. The effectiveness of herbicide spraying is influenced by the time of application, the time of rain, and the ability of the sprayer.
Keyword: Isopropilamina glyphosat, Systemic herbiside, Community coefficient, Spray calibration

Judul: Weeds Dominance According to the Pruning Years of Tea Plant (Camellia sinensis (L) O. Kuntze) at Negara Kanaan Tea Plantation, PT Ratnapura Bianka, Bandung
Abstrak: Budidaya tanaman teh tidak lepas dari keberadaan gulma. Dominansi gulma berdasarkan tahun pangkas perlu diketahui agar pengendalian gulma terlaksana dengan efektif. Kegiatan magang bertujuan menganalisis dominansi gulma menurut tahun pangkas tanaman teh. Hasil pengamatan menunjukkan bahwa gulma dominan yang tumbuh pada TP 1 dan TP 2 didominasi Oplismenus hirtellus sedangkan TP 3, 4, dan 5 didominasi Ageratum conyzoides. Nilai koefisien komunitas antar tahun pangkas kurang dari 70%, sehingga vegetasi gulma bersifat heterogen. Pengelolaan kerja pengendalian gulma berprinsip POACE. Pengendalian gulma dilaksanakan dengan metode manual menggunakan sabit dan kimiawi menggunakan knapsack sprayer. Herbisida yang digunakan berbahan aktif Isopropilamina glifosat dengan dosis antara 1,61-2,50 l ha-1. Pengendalian gulma kimiawi dilaksanakan dengan rotasi 3-6 bulan. Pekerja pengendalian gulma kimiawi dapat menyelesaikan 0,4 ha HK-1 pada TP 1 dan 0,5 ha HK-1 pada TP 2 hingga TP 4. Pekerja pengendalian gulma belum mematuhi kelengkapan APD yang ditetapkan perusahaan. Biaya pengendalian gulma pada TP 1 hingga TP 4 berkisar antara Rp541.971 hingga Rp1.004.928. Keberagaman gulma setiap tahun pangkas mempengaruhi kegiatan pengelolaan kerja pengendalian gulma secara umum., The cultivation of tea plants cannot be separated from the presence of weeds. Weed dominance by year of pruning needs to be known so that weed control is carried out effectively. The internship activity aims to analyze the dominance of weeds by year of pruning of tea plants. The results showed that the dominant weeds growing in TP 1 and TP 2 were dominated by Oplismenus hirtellus, while TP 3, 4, and 5 were dominated by Ageratum conyzoides. The community coefficient value between pruning years is less than 70%, so the weed vegetation is heterogeneous. Weed control work management is based on the POACE principle. Weed control is carried out manually using a sickle and chemically using a knapsack sprayer. The herbicide used as an active ingredient is Isopropylamine glyphosate with a dose between 1.61-2.50 l ha-1. Chemical weed control is carried out with a rotation of 3-6 months. Chemical weed control workers can complete 0.4 ha HK-1 at TP 1 and 0.5 ha HK-1 at TP 2 to TP 4. Weed control workers have not complied with the completeness of PPE set by the company. Weed control costs in TP 1 to TP 4 ranged from Rp. 541,971 to Rp. 1,004,928. The diversity of weeds each year affects weed control work management activities in general.
Keyword: Ageratum conyzoides, cost efficiency, herbicide, Oplismenus hirtellus, PPE

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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