Judul: Surface runoff and Soil Erosion in Pineapple  Plantation Land at PT Great Giant Pineapple, Central Lampung
Abstrak: Aliran permukaan dan erosi tanah sering menjadi masalah pada lahan pertanian karena dapat menyebabkan penurunan produktivitas tanah, pendangkalan badan air, dan penurunan kualitas air. Masalah yang dihadapi oleh PT Great Giant Pineapple (GGP) adalah pendangkalan badan air atau lebung, yang diduga disebabkan oleh erosi tanah di area perkebunan nanas. Aliran permukaan dan erosi tanah berkaitan erat dengan curah hujan dan tutupan tajuk tanaman. Oleh karena itu, perlu dilakukan identifikasi terhadap aliran permukaan dan erosi tanah di lahan perkebunan nanas PT GGP. Penelitian ini bertujuan untuk mengidentifikasi karakteristik aliran permukaan dan erosi di lahan perkebunan nanas PT GGP, Lampung Tengah. Pengukuran aliran permukaan dan erosi dilakukan pada petak erosi lahan perkebunan nanas umur tanaman 6 BST (Bulan Setelah Tanam), 9 BST dan 12 BST dengan kemiringan lahan 5 % - 10 %. Jenis tanah yang mendominasi lahan nanas di PT GGP adalah Ultisol. Aliran permukaan dan erosi memiliki hubungan yang lebih erat dengan curah hujan dibandingkan dengan tutupan tajuk tanaman. Semakin besar curah hujan maka aliran permukaan dan erosi tanah semakin besar. Aliran permukaan yang dihasilkan pada masing masing petak erosi dengan umur yang berbeda beda yaitu sebesar 6,43 liter untuk 6 BST, 2,93 liter untuk 9 BST dan 2,01 liter untuk 12 BST. Jumlah erosi yang terukur pada masing masing petak umur tanaman yaitu sebesar 6,35 ton/tahun/ha pada 6 BST, 2,76 ton/tahun/ha pada 9 BST, dan 1,37 ton/tahun/ha pada 12 BST., Surface runoff and soil erosion often pose problems on agricultural land because they can lead to decreased soil productivity, siltation of water bodies, and deterioration of water quality. The issue faced by PT Great Giant Pineapple (GGP) is the siltation of water bodies or ponds, which is suspected to be caused by soil erosion in the pineapple plantation area. Surface runoff and soil erosion are closely related to rainfall and plant canopy cover. Therefore, it is necessary to identify surface runoff and soil erosion in the pineapple plantation land of PT GGP. This study aims to identify the characteristics of surface runoff and erosion in the pineapple plantation land of PT GGP, Central Lampung. Measurements of surface runoff and erosion were conducted on erosion plots in the pineapple plantation land with plant ages of 6 months after planting (MAP), 9 MAP, and 12 MAP, with land slopes ranging from 5% to 10%. The type of soil that dominates the pineapple land at PT GGP is Ultisol. Surface runoff and erosion have a closer relationship with rainfall than with plant canopy cover. The greater the rainfall, the greater the surface runoff and soil erosion. The surface runoff produced on each erosion plot with different plant ages was 6.43 liters for 6 MAP, 2.93 liters for 9 MAP, and 2.01 liters for 12 MAP. The measured erosion amount on each plot for different plant ages was 6.35 tons/year/ha for 6 MAP, 2.76 tons/year/ha for 9 MAP, and 1.37 tons/year/ha for 12 MAP
Keyword: erosi tanah, aliran permukaan, perkebunan nanas, tutupan tajuk tanaman, surface runoff, soil erosion, pineapple plantation, canopy cover

Judul: Infiltrasi dan Penetrasi Tanah PT GGP Setelah Sebelas Bulan Aplikasi Bahan Organik Tahan Lapuk
Abstrak: Lahan PT Great Giant Pineapple (PT GGP) Lampung Tengah mengalami penurunan produktivitas akibat pengolahan lahan secara intensif selama 40 tahunan. Permasalahan yang dihadapi sejak tahun 2018 adalah rendahnya bahan organik dan terjadinya pemadatan tanah sehingga akar mengalami hambatan dalam menyuplai air dan hara yang dibutuhkan tanaman. Salah satu upaya untuk mengatasi pemadatan tanah di PT GGP adalah dengan pemberian bahan organik tahan lapuk seperti Limbah Ekstraksi Bromelain (LEB) dan Bambu Cacah (BC). Hal ini dilakukan karena penambahan bahan organik pada pertengahan fase umur nanas sulit dilakukan akibat kerapatan tanaman yang masif. Penelitian yang bertujuan untuk mengidentifikasi pengaruh bahan organik tahan lapuk setelah sebelas bulan aplikasi terhadap infiltrasi dan penetrasi tanah telah dilaksanakan di Lahan 88C2 Kebun PT GGP, Lampung Tengah. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok (RAK). Pengukuran infiltrasi dilakukan dengan menggunakan alat double ring infiltrometer sementara pengamatan penetrasi tanah menggunakan alat penetrometer saku. Nilai infiltrasi pada bulan ke-11 mengalami penurunan dibandingkan dengan bulan ke-1 dan bulan ke-5 sedangkan nilai penetrasi tanahnya mengalami peningkatan. Penurunan infiltrasi dan peningkatan penetrasi pada bulan ke-5 dan ke-11 sudah menunjukkan pola mendatar. Peningkatan dosis bahan organik yang diberikan berpengaruh terhadap peningkatan nilai penetrasi dan menyebabkan penurunan infiltrasi setelah sebelas bulan aplikasi., The agricultural land of PT Great Giant Pineapple (PT GGP) Central Lampung experienced a decrease in productivity due to intensive land management during 40 years. The problem occurred since 2018 concerning low organic matter content and soil compaction so that the roots experience obstacles in supplying water and nutrients needed by plants. One of the efforts to overcome soil compaction at PT GGP is by providing a resistant organic matter such as Bromelain Extraction Waste and Chopped Bamboo trees since the addition of organic matter in the middle of the pineapple growth phase is difficult due to the massive density of the plant. Research aimed to identify the influence of a resistant organic matter after eleven months of application on soil infiltration and soil penetration resistant (SPR) has been carried out on Plantation Land 88C2 of PT GGP, Central Lampung. The research used the Randomized Block Design (RBD) method. Infiltration measurement was carried out using a double ring infiltrometer while SPR observation was carried out using a pocket penetrometer. The infiltration value after eleven months of application decreased compared to the value of the first month and the fifth month of application while the SPR value increased. The decrease in infiltration and increase in SPR in the fifth and eleven months have already leveled off. The increase of organic matter dose applied after eleven months of application has affected to increase the SPR value and lead to decrease soil infiltration.
Keyword: chopped bamboo, bromelain extraction waste, soil compaction, resistant

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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