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: Permeability and Shear Strength of PT GGP Pineapple Land after Eleven Months of Resistant Organic Matter Application
Abstrak: Penurunan produktivitas pertanian pada umumnya disebabkan oleh penurunan kualitas tanah akibat penggunaan terus-menerus. Penelitian ini dilakukan pada lahan PT Great Giant Pineapple (GGP) yang mengalami penurunan produktivitas buah nanas seiring terjadinya penurunan kualitas tanah. Penurunan kualitas tanah terjadi karena rendahnya pemberian bahan organik yang sesuai dengan usia tanaman nanas, sehingga mengakibatkan pemadatan tanah. Dalam penelitian ini, limbah ekstraksi bromelain dan bambu cacah dipilih sebagai sumber bahan organik tahan lapuk karena mampu mempertahankan residence time pada pengaplikasian nya di lahan. Tujuan penelitian adalah menguji pengaruh bahan organik tahan lapuk setelah 11 bulan aplikasi terhadap permeabilitas dan kuat geser tanah. Metode penelitian yang digunakan adalah rancangan acak kelompok (RAK) di lokasi lahan 88 C2, PT GGP, Lampung Tengah. Hasil penelitian menunjukkan bahwa perlakuan limbah ekstraksi bromelain menghasilkan nilai laju permeabilitas yang lebih rendah dibandingkan dengan perlakuan bambu cacah. Laju permeabilitas pada kedua perlakuan mengalami penurunan setelah 11 bulan aplikasi bahan organik dibandingkan dengan setelah aplikasi 5 bulan. Nilai Kekuatan geser tanah meningkat seiring bertambahnya usia tanaman pada bulan 11, terutama pada kedalaman 0-10 cm, 10-20 cm, dan 20-30 cm. Pemberian dosis bahan organik yang lebih tinggi memberikan perbaikan sifat fisik tanah yang lebih baik., The decline in agricultural productivity is generally caused by a decrease in soil quality due to continuous use. This research was conducted on PT Great Giant Pineapple (GGP)’s land which experienced a decrease in pineapple productivity along with a decrease in soil physical quality. The decline in soil quality occurred due to the low provision of organic matter in accordance with the age of pineapple plants, resulting in soil compaction. In this study, bromelain extraction waste and chopped bamboo were chosen as a source of resistant organic matter since they are able to maintain quite long residence time in land after application. The research objective was to examine the effect of resistant organic matter after 11 months of application on permeability and soil shear strength. The research was held based on Randomized Block Design (RBD) at the location of 88 C2 land of PT GGP, Central Lampung. The results showed that the bromelain extraction waste treatment produced a lower permeability rate than the chopped bamboo treatment. The permeability rate in both treatments decreased after 11 months of organic matter application compared to the 5 months of application. Soil shear strength values increased with plant age of month 11, especially at depths of 0-10 cm, 10-20 cm, and 20-30 cm. Application of higher doses of resistant organic matter provided better improvements in soil physical properties.
Keyword: bromelain, organic matter, permeability, shear strength

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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