Judul: Pemberian Pupuk Kandang Ayam dan Frekuensi Penyiraman untuk Perbaikan Sifat Fisik Tanah Pasir Simulasi Tailing Tambang dan Pertumbuhan Tanaman Bayam
Abstrak: Mining activities cause various effects such as reduced agricultural land, fertile land, and decreased function of environment. One of mine waste material is sand tailings. Utilization of sand tailings as growing media faces physical, chemical, and biological problems due to its very high sand fraction and very low organic matter content. This study aims to evaluate the effect of chicken manure and watering frequency to improve physical of soil simulation sand mine tailings and their effect on spinach growth. The design used was a completely randomized design with 2 factors and 3 replications. The first factor was the chicken manure doses of 0, 10, and 20 tons/ha. The second factor was the watering frequency of 2, 4, and 6 days with a volume of 750 ml / pot for each watering. The results show that chicken manure significantly increase the available pore water, but does not significantly affect the bulk density, total pore space, as well as pore drainage of the soil. Watering frequency treatment has no significant influence on the physical properties of the soil. Spinach as indicator plants can grow and adapt to the media of simulated mine tailings with and without chicken manure, watered either 2, 4, or 6 days. Chicken manure significantly affects plant height at 40 HST, but does not on the number of leaves and the weight of the plant. Spinach responses better to the application chicken manure of 10 ton/ha and 20 ton/ha than control. Treatment frequency of watering significantly affects all plant growth parameters observed. Frequency of watering two (2) days provide worse spinach production compare to the frequency of watering four (4) and six (6) days due to waterlogging and translocation of particles.
Keyword: Bogor Agricultural University, chicken manure, mine tailings sand, spinach, watering frequency

Judul: Optimization of Spinach Fertilization Based on Soil Analysis Using Fertigation Through Drip Irrigation Systems
Abstrak: Pemupukan melalui irigasi tetes berdasarkan analisis tanah diharapkan dapat meningkatkan produktivitas bayam varietas Maestro. Penelitian dilaksanakan di Kebun Percobaan Cikarawang, Institut Pertanian Bogor dengan jenis tanah latosol, kandungan P-tersedia 3,9 ppm (sangat rendah), K-tersedia 40,2 ppm (sedang), C Organik 1,92%, dan pH 5,83. Penelitian ini bertujuan mendapatkan dosis rekomendasi pemupukan yang tepat untuk bayam berdasarkan hasil analisis tanah melalui sistem irigasi tetes dan menguji pengaruh potensi pupuk untuk dua kali tanam tanpa preplant dan fertigasi. Penelitian terdiri dari dua kali penanaman menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktor Tunggal dengan 5 ulangan dan 5 taraf pemupukan yaitu 0% X, 50% X, 100% X, 150% X, dan 200% X (X adalah rekomendasi berdasarkan program Ferads). Data dianalisis menggunakan uji-F dengan α 5% dan uji lanjut menggunakan analisis regresi. Hasil penelitian menunjukkan pada penanaman pertama didapatkan dosis optimum untuk bobot per bedeng marketable, bobot per bedeng total, perkiraan bobot panen per hektar marketable, dan perkiraan bobot panen per hektar total berturut-turut yaitu sebesar 151%, 133%, 135%, dan 132% dari dosis rekomendasi Ferads (219 kg N ha-1 , 274 kg P2O5 ha-1 , dan 149 kg K2O ha-1 ). Dosis 100% rekomendasi Ferads digunakan karena kenaikan hasil tidak signifikan meskipun diberikan dosis pupuk yang lebih tinggi. Dosis optimum tidak diperoleh pada penanaman kedua karena hasil analisis regresi tidak menunjukkan respon kuadratik. Residu pemupukan tidak mempengaruhi produksi bayam varietas Maestro secara keseluruhan sehingga analisis tanah perlu dilakukan di setiap musim tanam bayam., Fertilization through drip irrigation based on soil analysis is expected to increase the productivity of Maestro spinach varieties. The research was carried out at the Cikarawang Experimental Garden, Bogor Agricultural Institute with latosol soil type, P-available content of 3.9 ppm (very low), K-available 40.2 ppm (medium), C-Organic 1.92%, and pH 5 .83. This research aims to obtain the correct recommended dose of fertilizer for spinach based on the results of soil analysis using a drip irrigation system and testing the potential effect of fertilizer for two plantings without preplant and fertigation. The research consisted of two plantings using a single factor Randomized Complete Group Design (RKLT) with 5 replications and 5 levels of fertilization, namely 0% X, 50% X, 100% X, 150% X, and 200% X (X was a recommendation based on the Ferads program). Data were analyzed using F-test with α 5% and further testing using regression analysis. The results of the research showed that in the first planting, the optimum dose was obtained for weight per marketable bed, total weight per bed, estimated marketable harvest weight per hectare, and estimated total harvest weight per hectare respectively, namely 151%, 133%, 135%, and 132%. % of Ferads recommended dose (219 kg N ha-1 , 274 kg P2O5 ha-1 , and 149 kg K2O ha-1 ). The 100% dose recommended by Ferads was used because the increase in yield was not significant even though a higher fertilizer dose was given. The optimum dose was not obtained in the second planting because the results of the regression analysis did not show a quadratic response. Fertilizer residue does not affect the overall production of the Maestro spinach
Keyword: Ferads, fertigation, fertilizer dose, production, spinach

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix