Judul: Utilization of Resistant Organic Materials to Improve Soil Physical Properties (Infiltration and Penetrability)
Abstrak: Permasalahan utama tanah di kebun PT. Great Giant Pineapple (GGP) yaitu kandungan bahan organik yang rendah dan terjadinya pemadatan tanah. Pemadatan tanah sampai tahap tertentu dapat diatasi dengan perlakuan mekanik yang memaksa partikel tanah saling menjauh dan pemberian bahan organik untuk memicu proses agregasi tanah dan meningkatkan kemampuan menahan air, meningkatkan nilai infiltrasi tanah dan menurunkan nilai ketahanan penetrasi tanah. Penelitian ini bertujuan mengidentifikasi pengaruh aplikasi serat limbah ekstraksi bromelain dan bambu cacah terhadap infiltrasi dan ketahanan penetrasi tanah pada berbagai dosis bahan organik. Pengukuran infiltrasi konstan dilakukan dengan menggunakan alat infiltrometer dan pengamatan ketahanan penetrasi dilakukan dengan menggunakan alat penetrometer saku dan penetrologger. Kapasitas infiltrasi pada perlakuan limbah ekstraksi bromelain memiliki nilai awal sebesar 44,73 cm/jam pada bulan ke-1 dan nilai akhir sebesar 9,32 cm/jam pada bulan ke-5, sedangkan pada perlakuan bambu cacah memiliki nilai awal sebesar 47,26 cm/jam pada bulan ke-1 dan nilai akhir 15,18 cm/jam pada bulan ke-5. Ketahanan penetrasi tanah pada petak perlakuan bambu cacah memiliki nilai relatif lebih rendah dibandingkan dengan petak perlakuan limbah pemrosesan bromelain pada semua kedalaman pada bulan ke-1, bulan ke-3 dan bulan ke-5. Kurva penetrologger menunjukkan bahwa petak perlakuan limbah ekstraksi bromelain pada bulan ke-3 dan bulan ke-5 memiliki nilai relatif lebih tinggi dibandingkan petak perlakuan bambu cacah. Berdasarkan pengamatan, petak limbah ekstraksi bromelain dan bambu cacah berdampak baik terhadap infiltrasi konstan dan penetrasi tanah., The main problem of soil in PT. Great Giant Pineapple (GGP) namely are low of organic matter content and the occurrence of soil compaction. Soil compaction to a certain extent can be overcome by mechanical treatment which forces soil particles away from each other and the application of organic matter to trigger the soil aggregation process and increase the ability to hold water, to increase the infiltration and lowering the penetration resistance of soil. This study aims to identify the effect of the application of bromelain extraction waste product and chopped bamboo on soil infiltration and soil penetration resistence. Constant infiltration measurements were carried out using an infiltrometer and penetration resistance observations were carried out using a pocket penetrometer and a penetrologger. The infiltration capacity in the bromelain extraction waste product had an initial value of 44.73 cm/hour in the 1st month and a final value of 9.12 cm/hour in the 5th month, while in the chopped bamboo treatment it had an initial value of 43.78 cm/hour in the 1st month and a final value of 15.18 cm/hour at the 5th month. The soil penetration resistance of the chopped bamboo treatment plots had a relatively lower value compared to the bromelain extraction waste product treatment plots at all depths either at the 1st, 3rd or 5th month. The penetrologger curve shows that the plots treated with bromelain extraction waste product at the 3rd month and the 5th month had a relatively higher value than the plots treated with chopped bamboo. Based on observations, bromelain extraction waste product and chopped bamboo application had a positif effect on constant infiltration and soil penetration resistance.
Keyword: amelioran, bromelain extraction waste, chopped bamboo, penetrologger, soil compaction

Judul: Utilization of Weatherable Organik Materials for Improvement of Soil Physical Properties (Soil Permeability and Shear Strength)
Abstrak: Penurunan produktivitas pertanian di Indonesia umumnya disebabkan oleh terjadinya penurunan kualitas tanah akibat penggunaan tanah secara terus-menerus. Penurunan produktivitas juga dialami oleh PT Great Giant Pineapple (GGP) sejak 2018. Hal tersebut terjadi karena kandungan bahan organik yang rendah dan terjadinya pemadatan tanah. Pemadatan tanah dapat diatasi dengan pemberian bahan organik. Pemberian bahan organik sering mengalami kendala akibat residence time-nya yang relatif singkat terutama untuk tanaman berumur panjang seperti nanas. Salah satu alternatif adalah dengan memanfaatkan limbah ekstraksi bromelain yang tersedia. Penelitian ini bertujuan mengidentikasi pengaruh aplikasi limbah ekstraksi bromelain dan bambu cacah berbagai dosis terhadap proses agregasi, kekuatan geser tanah dan permeabilitas tanah. Penelitian dilakukan di lokasi 88 C2 Kebun PT GGP, Lampung Tengah dengan metode rancangan acak kelompok (RAK) faktorial. Tanah dengan perlakuan limbah ekstraksi bromelain memiliki indeks stabilitas agregat tanah yang lebih tinggi dibandingkan tanah dengan perlakuan bambu cacah. Laju permeabilitas tanah mengalami penurunan pada 5 bulan setelah aplikasi bahan organik baik pada limbah ekstraksi bromelain maupun bambu cacah. Pemberian bahan organik memicu pertumbuhan akar tanaman nanas sehingga meningkatkan nilai kekuatan geser tanah. Semakin tinggi dosis bahan organik yang diberikan maka semakin baik dampaknya terhadap sifat fisik tanah., The decline in agricultural productivity in Indonesia is generally caused by a decrease in soil quality due to continuous land use. PT Great Giant Pineapple (GGP) has also experienced a decline in productivity since 2018. This is due to the low organik matter content and soil compaction. Soil compaction can be overcome by adding organik matter. The application of organik matter often experiences problems due to its relatively short residence time, especially for long-lived plants such as pineapple. One alternative is to utilize the available bromelain extraction waste. This study aims to identify the effect of the application of bromelain extraction waste and various doses of chopped bamboo on the aggregation process, soil shear strength and soil permeability. The research was conducted at location 88 C2 of PT GGP's plantation, Central Lampung with a factorial randomized block design (RBD) method. Soil treated with bromelain waste extraction had a higher soil aggregate stability index than soil treated with chopped bamboo. The rate of soil permeability decreased 5 months after the application of organik matter in both bromelain extraction waste and chopped bamboo. The application of organik matter triggers the growth of pineapple plant roots thereby increasing the shear strength value of the soil. The higher the dose of organik matter given, the better the impact on soil physical properties.
Keyword: aggregate stability, bromelain, residence time, soil compaction

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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