Tingkat Bahaya Erosi Pada Perkebunan Kelapa Sawit di Kota Subulussalam

Abstrak. Penelitian ini bertujuan untuk mengetahui tingkat bahaya erosi pada perkebunan kelapa sawit di Kota Subulussalam. Metode penelitian menggunakan metode deskriftif yang didasarkan pada hasil pengamatan di lapangan dan analisis tanah di laboratorium. Erosi tanah dihitung dengan menggunakan persamaan Universal Soil Loss Equation (USLE) yang dikemukakan oleh Wischmeir dan Smith (1978). Metode USLE mengamati beberapa aspek seperti erosivitas, erodibilitas, faktor panjang dan kemiringan lereng, faktor pengelolaan tanaman dan tindakan konservasi. Penelitian ini terdiri dari beberapa tahap yaitu, persiapan, pengumpulan data, pelaksanaan lapangan, analisis laboratorium dan analisis data. Hasil penelitian menunjukkkan bahwa pada lokasi penelitian ini terdapat enam satuan peta lahan (SPL) dengan total luas 2437,83 Hektar. Erosi potensial tertinggi dijumpai pada SPL 2 yaitu sebesar 6762,10 ton ha-1 th-1 dan erosi potensial terendah dijumpai pada SPL 1 yaitu 172,01 ton ha-1 th-1. Erosi aktual tertinggi dijumpai pada SPL 2 yaitu sebesar 473,35 ton ha-1 th-1 dan erosi aktual terendah dijumpai pada SPL 5 yaitu 9,58 ton ha-1 th-1. Terdapat 3 klasifikasi tingkat bahaya erosi yaitu tingkat bahaya erosi ringan (R) pada SPL 1, SPL 5, dan SPL 6, tingkat bahaya erosi sedang (S) pada SPL 3, dan tingkat bahaya erosi berat (B) pada SPL 2 dan SPL 4.The Level of Erosion Hazard at Oil Palm Plantation in Subulussalam CityAbstrak. This study aims to determine the level of erosion hazard in palm oil plantations in Subulussalam City. The research method uses a descriptive method based on field observations and soil analysis in the laboratory. Soil erosion is calculated by using the formula of Universal Soil Loss Equation (USLE) which is invented by Wischmeir and Smith (1978). The USLE method observes several aspects such as erosivity, erodibility, length and slope factors, crop management factors and conservation actions. This research consists of several stages, namely, preparation, data collection, field implementation, laboratory analysis and data analysis. The results of the study showed that at the location of this study there were six units of land maps (SST) with a total area of 2437.83 hectares. The highest potential erosion was found in SPL 2 which was 6762.10 tons ha-1 th-1 and the lowest potential erosion was found in SPL 1 which was 172.01 tons ha-1 th-1. The highest actual erosion was found in SPL 2 which was 473.35 tons ha-1 th-1 and the lowest actual erosion was found in SPL 5 which was 9.58 tons ha-1 th-1. There are 3 classifications of the level of erosion hazard namely the level of light erosion hazard (R) in SPL 1, SPL 5, and SPL 6, the level of moderate erosion hazard (S) in SPL 3, and the level of severe erosion hazard (B) in SPL 2 and SPL 4.

Download Full-text

Prediksi Tingkat Bahaya Erosi di Kecamatan Lembah Seulawah Kabupaten Aceh Besar

Jurnal Ilmiah Mahasiswa Pertanian ◽

10.17969/jimfp.v3i2.7467 ◽

2018 ◽

Vol 3 (2) ◽

pp. 381-390

Author(s):

M. Haris Syahputra ◽

M. Rusli Alibasyah ◽

Syakur Syakur

Keyword(s):

Soil Loss ◽

Soil Analysis ◽

Universal Soil Loss Equation ◽

Survey Method ◽

Erosion Hazard ◽

Preparation Phase ◽

Hazard Level ◽

Study Sites ◽

Th 1 ◽

Soil Loss Equation

Abstrak. Penelitian ini bertujuan untuk mengetahui tingkat bahaya erosi di Kecamatan Lembah Seulawah Kabupaten Aceh Besar. Metode penelitian menggunakan metode survei yang didasarkan pada hasil pengamatan di lapangan dan analisis tanah di Laboratorium. Erosi dihitung dengan menggunakan persamaan Universal Soil Loss Equation (USLE) yang dikemukakan oleh Wischmeier dan Smith pada tahun 1978. Metode USLE mengamati beberapa aspek seperti erosivitas, erodibilitas, faktor panjang dan kemiringan lereng, dan faktor pengelolaan tanaman dan tindakan konservasi. Secara garis besar penelitian ini dilaksanakan beberapa tahap yaitu, tahap persiapan, pengumpulan data, pelaksanaan lapangan dan pengambilan sampel tanah, dan analisis data. Hasil penelitian menunjukkan bahwa di lokasi penelitian terdapat tujuh belas satuan peta lahan (SPL) dengan total luas areal 31.935,56 Hektar. Erosi aktual tertinggi dijumpai pada SPL 7 yaitu sebesar 2.699,92 ton ha-1 th-1 dan erosi aktual terendah dijumpai pada SPL 14 yaitu 0,82 ton ha-1 th-1. Erosi potensial tertinggi dijumpai pada SPL 1 yaitu sebesar 5.774,84 ton ha-1 th-1 dan erosi potensial terendah dijumpai pada SPL 16 yaitu 48,53 ton ha-1 th-1. Terdapat 5 klasifikasi tingkat bahaya erosi yaitu tingkat bahaya erosi sangat ringan (SR) pada SPL 16, tingkat bahaya erosi ringan (R) pada SPL 17, tingkat bahaya erosi sedang (S) pada SPL 10, 14, dan 15, tingkat bahaya erosi berat (B) pada SPL 4, 7, 11, 12, dan 13, dan tingkat bahaya erosi sangat berat (SB) pada SPL 1, 2, 3, 5, 6, 8, dan 9.Prediction of Erosion Hazard at Lembah Seulawah Sub-distrik Aceh BesarAbstract. This study aims to determine the level of erosion hazard in Lembah Seulawah, Aceh Besar District. The research method is used survey method based on field observation and soil analysis in the laboratory. Erosion is calculated by using the Universal Soil Loss Equation (USLE) which proposed by Wischmeier and Smith in 1978. The USLE method looked at several aspects such as erosivity, erodibility, long factor and slope, and crops management and conservation measures. In general, this research is carried out several stages, namely, preparation phase, data collection, field implementation and soil sampling, and data analysis. The results showed that in the study sites there were seventeen units of land maps (SPL) with a total area of 31,935.56 hectares. The highest actual erosion was found in SPL 7 of 2,699.92 tons ha-1 th-1 and the lowest actual erosion was found in SPL 14 of 0.82 tons ha-1 th-1. The highest potential erosion was found in SPL 1 of 5,774.84 ton ha-1 th-1 and the lowest potential erosion was found in SPL 16 of 48.53 ton ha-1 th-1. There are 5 classifications of erosion hazard level which is very light erosion (SR) on SPL 16, light erosion hazard (R) on SPL 17, moderate erosion level (S) on SPL 10, 14, and 15, (B) on SPL 4, 7, 11, 12, and 13, and very severe erosion (SB) on SPL 1, 2, 3, 5, 6, 8, and 9.

Download Full-text

Pengukuran erosi pada pertanaman kentang dan jagung padabeberapa kemiringan di desa Guru SingaKabupaten Karo dengan metode USLE

Jurnal Pertanian Tropik ◽

10.32734/jpt.v5i1.3133 ◽

2018 ◽

Vol 5 (1) ◽

pp. 36-39

Author(s):

Ananda P Harahap ◽

Hardy Guchi ◽

Jamilah

Keyword(s):

Soil Erosion ◽

Soil Loss ◽

Soil Analysis ◽

Middle Level ◽

Land Conservation ◽

Universal Soil Loss Equation ◽

Potato Field ◽

Erosion Hazard ◽

Soil Loss Equation ◽

Selection Of

The type of plant and selection of conservation techniques greatly influence the extent of erosion. The aim of this study was to measure the value of the erosion in the field of potato and corn with the slopes by using USLE method (Universal Soil Loss Equation). This study had been implemented in the fields of potato and corn with a slope 0-3, 3-8%,8-15%, 15-25% and 25-45% in Guru Singa village, Berastagi sub-district, Karo district started on April until October 2016. Soil analysis was carried out in Research Laboratories and Technological Faculty of Agriculture, Universitas Sumatera Utara. The result showed that the amount of erosion occurred in the potato field. The field planted by contour direction in slope 0 – 3 % was 4,55 ton ha-1 yr-1 with the low level of erosion hazard. The highest level of erosion hazard in slope 8 – 15 % was 112,57ton ha-1 yr-1. The highest level of erosion hazard in slope 15 – 25 % was 160,97ton ha-1 yr-1. Based on data from the cornfield planted by cutting on contour, the amount of erosion in slope 3 – 8 % was 15,61ton ha-1 yr-1with the middle level of erosion hazard. The highest level of erosion hazard in slope 25 – 45% was 106,08ton ha-1 yr-1. It is required to do the changing of land conservation in order to minimize the risk of erosion or at least equal to the soil erosion tolerated.

Download Full-text

Estimasi Tingkat Bahaya Erosi dengan Menggunakan Metode USLE Pada Daerah Aliran Sungai (DAS) Amandit

Indonesian Journal of Earth Sciences ◽

10.52562/injoes.v1i1.20 ◽

2021 ◽

Vol 1 (1) ◽

pp. 17-27

Author(s):

Julita Safitri ◽

Deasy Arisanty ◽

Sidharta Adyatma ◽

Karunia Puji Hastuti

Keyword(s):

Data Analysis ◽

Soil Erosion ◽

Land Cover ◽

Land Degradation ◽

Soil Loss ◽

Universal Soil Loss Equation ◽

Erosion Hazard ◽

Hazard Level ◽

Weight Classification ◽

Soil Loss Equation

Abstrak: Erosi tanah menjadi semakin meningkat setiap tahun yang disebabkan oleh terjadinya peningkatan kerusakan lahan. Daerah Aliran Sungai (DAS) Amandit mengalami kerusakan lahan yang ditandai dengan luasnya lahan kritis pada DAS tersebut yang akan berpengaruh pada tingginya tingkat bahaya erosi pada DAS tersebut. Penelitian ini bertujuan untuk menganalisis tingkat bahaya erosi yang terjadi pada Daerah Aliran Sungai (DAS) Amandit. Penelitian ini menggunakan peta bentuklahan sebagai dasar pengambilan sampel. Jumlah sampel dalam penelitian ini adalah 18 buah sampel. Analisa data yang digunakan adalah berdasarkan Metode Universal Soil Loss Equation (USLE) yang digunakan untuk mengetahui tingkat bahaya erosi yang terjadi pada wilayah penelitian. Hasil penelitian menunjukkan tingkat bahaya erosi yang terjadi di Daerah Aliran Sungai (DAS) Amandit termasuk dalam klasifikasi berat-sangat berat. Tingkat bahaya erosi yang paling tinggi adalah 1276.535 ton/ha/tahun. Faktor yang dominan yang mengakibatkan tingkat bahaya erosi pada Daerah Aliran Sungai (DAS) Amandit termasuk dalam klasifikasi berat-sangat berat adalah kemiringan lereng, nilai erodibilitas yang tinggi, dan tutupan lahan. Kata Kunci: Tingkat Bahaya Erosi (TBE), Bentuklahan, USLE, DAS Amandit Abstract: Soil erosion is increasing every year due to increased land degradation. The Amandit Watershed has suffered damage which affects critical land in the watershed which will affect the level of erosion hazard in the watershed. This study aims to analyze the level of erosion that occurs in the Amandit Watershed. This study uses a landform map as a basis for sampling. The number of samples in this study were 18 samples. The data analysis used is based on the Universal Soil Loss Equation (USLE) method which is used to see the level of erosion hazard that occurs in the study area. The results showed that the level of erosion that occurred in the Amandit Watershed was classified as heavy-very heavy. The highest level of erosion was 1276.535 ton/ha/year. The dominant factors resulting in the level of erosion in the watershed (DAS) included in the weight-very weight classification are the slope of the slope, high erodibility values and land cover. Keywords: Erosion Hazard Level, Landform, USLE, Amandit Watershed

Download Full-text

Analisis Spasial dan Basis Data Tingkat Bahaya Erosi dengan Menggunakan Sistem Informasi Geografis dan Visual Basic

Rona Teknik Pertanian ◽

10.17969/rtp.v12i2.13043 ◽

2019 ◽

Vol 12 (2) ◽

pp. 23-38

Author(s):

Dewi Sri Jayanti ◽

Maulidawati Maulidawati ◽

Mahbahgie Mahbahgie

Keyword(s):

Information System ◽

Geographic Information System ◽

Soil Loss ◽

Erosion Rate ◽

Source Code ◽

Visual Basic ◽

Geographic Information ◽

Universal Soil Loss Equation ◽

Erosion Hazard ◽

Soil Loss Equation

Erosi mengakibatkan kerusakan fungsi hidrologis daerah aliran sungai, juga kehilangan lapisan tanah yang subur dan baik untuk pertumbuhan tanaman serta kemampuan tanah dalam menyerap dan menahan air menjadi berkurang. Penyusunan basis data tingkat bahaya erosi ini diharapkan dapat memberikan informasi yang akurat dan up to date mengenai potensi tingkat bahaya erosi yang terjadi di wilayah Sub DAS Krueng Keumireu. Sub DAS Krueng Keumireu merupakan bagian dari DAS Krueng Aceh yang termasuk ke dalam sungai dengan prioritas I. Penelitian ini bertujuan untuk menduga tingkat bahaya erosi dan menyusun aplikasi basis data dengan menggunakan sistem informasi geografis dan Visual Basic 2010. Metode yang digunakan untuk pendugaan laju erosi yang terjadi menggunakan metode USLE (Universal Soil Loss Equation), pengelolaan data-data spasial menggunakan Sistem Informasi Geografi dan penyususan basis data menggunakan Visual Basic.Net 2010. Hasil penelitian menunjukkan bahwa kondisi Sub DAS Krueng Keumireu masih dalam kategori sangat ringan hingga ringan dengan persentase 38% kategori sangat ringan dan 36% kategori ringan dengan laju bahaya erosi tertinggi sebesar 1.388,8843 ton/ha/tahun dan laju bahaya erosi terendah sebesar 0,1618 ton/ha/tahun. Sehingga upaya konservasi yang dapat dilakukan dengan pemberian mulsa mau pun pengelolaan Program aplikasi basis data sudah dapat dijalankan dengan baik tanpa ada kesalahan source code sehingga informasi tingkat bahaya erosi yang ditampilkan sudah dapat diakses oleh user.Spatial Analysis and Erosion Hazard Level Database by Using Geographic Information System and Visual Basic.Erosion results in damage to the hydrological function of the watershed, as well as the loss of fertile soil layers and good for plant growth and the ability of the soil to absorb and retain water becomes reduced. Preparation of erosion hazard data base expected to provide accurate and information up to date about the potential level of erosion hazard that occurs in the Krueng Keumireu Sub-watershed area. Krueng Keumireu Sub-watershed is part of the Krueng Aceh watershed which belongs to the river with priority I. This study aims to estimate the level of erosion hazard and develop database applications using geographic information systems and Visual Basic 2010. The method used to estimate the rate of erosion occurred using the USLE (Universal Soil Loss Equation) method, spatial data management using Geographic Information System and database deduction using Visual Basic.Net 2010. The results showed that the condition of Krueng Keumireu Sub watershed is still in very light to light category with the percentage 38 % very light category and 36% light category with the highest erosion rate of 1,388,8843 ton/ha/year and the lowest erosion rate of 0,1618 ton/ha/year. So with such conditions can be carried out conservation efforts such as mulching and land management in a simple way. Database application program can be run properly without any error source code so that the information level of erosion hazard that displayed can be accessed by the user.

Download Full-text

Pendugaan tingkat bahaya erosi pada hutan dan lahan Kopi Arabika (Coffea arabica) di Kecamatan Sibolangit

Jurnal Pertanian Tropik ◽

10.32734/jpt.v5i1.3131 ◽

2018 ◽

Vol 5 (1) ◽

pp. 30-35

Author(s):

Devisna Situngkir ◽

Jamilah ◽

Posma Marbun

Keyword(s):

Soil Loss ◽

Prediction Equation ◽

Universal Soil Loss Equation ◽

Survey Method ◽

Land Use Patterns ◽

Factors Affecting ◽

Erosion Hazard ◽

Coffee Arabica ◽

Hazard Level ◽

Soil Loss Equation

Vegetation is one of the factors affecting the actual erosion of a land. The changes in forest land use patterns into coffee lands can increase the erosion hazard. The aim of this research was to get information about erosion hazard level in forest and coffee arabica lands in Sibolangit Sub District by using USLE (Universal Soil Loss Equation) method. The Research was conducted in January-July 2017 in Sibolangit District at three villages ie Negeri Suah, Bukum and Cinta Rakyat. In this research, were 6 samples in Arabica coffee field sample (1, 2 and 3) and in Forest sample (1, 2 and 3). The research was conducted by using survey method and continued with soil erosion calculation by USLE (Universal Soil Loss Equation) prediction equation. The results showed that the value of erosion in the coffee arabica land in Cinta Rakyat Village on the slope of 60% was 432,87 ton.ha-1.year-1 (very high). The highest erosion hazard level in Bukum Village on the slope of 25% was 88,144 ton.ha-1.year-1 and the highest erosion hazard level in the Negeri Suah Village on the slope of 46% was 193,083 ton.ha-1.year-1. The value of erosion in the area forest in the Cinta Rakyat Forest on the slope 58% was 1,087 ton.ha-1.year-1with lowest erosion hazard. The lowest erosion hazard level in the Bukum Forest on the slope of 21% was 0,190 ton.ha-1.year-1and the lowest erosion hazard level in the Negeri Suah Forest on the slope of 36 % was 0,309 ton.ha-1.year-1.

Download Full-text

Assessment of Soil Erosion Hazard in Prambanan District Using RUSLE (Revised Universal Soil Loss Equation)

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/884/1/012010 ◽

2021 ◽

Vol 884 (1) ◽

pp. 012010

Author(s):

S. A Mulya ◽

N. Khotimah

Keyword(s):

Soil Loss ◽

Hazard Index ◽

Universal Soil Loss Equation ◽

Annual Rainfall ◽

Rainfall Erosivity ◽

Slope Length ◽

Erosion Hazard ◽

Erosion Processes ◽

Factor C ◽

Soil Loss Equation

Abstract Prambanan District which located in Daerah Istimewa Yogyakarta Province has the potential for land degradation due to erosion processes. With the characteristics of annual rainfall more than 2000 mm / year, topography with a slope of more than 20% in upland areas, as well as the conversion of upland to dryland agriculture are factors that can trigger the erosion process more quickly. If the rate of erosion speed exceeds the ability of the soil to regenerate the soil body, its productivity will be disrupted and accelerate the formation of critical soil. Therefore, it is necessary to know the estimated rate of erosion, tolerable distribution of erosion, and the potential danger of erosion that occurs. The purpose of this study was to (1) predict the rate of erosion, (2) calculate the permissible erosion value, (3) identify the rate & index of erosion hazard. Data were collected using field surveys and soil sampling using stratified random sampling techniques with land units as the unit of analysis. The value of erosion was predicted using the Revised Universal Soil Loss Equation (RUSLE) method. The RUSLE method is described by the following equation, A=R*K*L*S*C*P, where; A as estimated averages annual loss of soil, R is the rainfall erosivity factor, K is the soil erodibility factor, LS is the slope length factor, C is the cover management factor, & P is the conservation practice factor. The results showed that the erosion value ranged from 0.39 - 268.55 tons/ha/year. Permissible erosion ranges from 8.4 – 15 tons/ha/year for Latosol and 27.4 ton/ha/year for Regosol. The Rate of Erosion Hazard is dominated by moderate erosion, covering an area of 1330.7 ha or 31.8% of the total area. The Erosion Hazard Index is dominated by the low class (<1.0) which is covered over 2703.1 ha or 64.61% of the total area.

Download Full-text

Erosion and sedimentation analysis due to land use changes in the Krueng Pase watershed

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/922/1/012040 ◽

2021 ◽

Vol 922 (1) ◽

pp. 012040

Author(s):

Muntazar ◽

Joni ◽

I Ramli

Keyword(s):

Land Use ◽

Soil Loss ◽

Negative Impact ◽

Positive Impact ◽

Land Use Changes ◽

Appropriate Technology ◽

Universal Soil Loss Equation ◽

Erosion Hazard ◽

Land Management System ◽

Soil Loss Equation

Abstract Human interactions with watershed can have positive and negative impact. The positive impact can improve socio-economic conditions. However, the negative impact is the degradation of the watershed function. For example, it’s continued increase in erosion rate on the land. The purpose of this study is to analyze erosion and sedimentation due to land use changes using the Universal Soil Loss Equation (USLE) and Modified Universal Soil Loss Equation (MUSLE) methods. Data collecting to determine erosion and sedimentation values are rainfall, soil erodibility and soil moisture, land use, and river water samples. The biggest decreased land use changes occurred in forest by 5.87%, followed by agriculture which decreased by 0.65% and water body 0.047%. On the other hand, built-up area increased by 0.65% and land used for agriculture increased by 6.15%. Furthermore, the level of erosion hazard in the Krueng Pase watershed from 2009 to 2019 increased in area, the mild level of erosion hazard increased by 7.9% and the moderate level erosion hazard by 27.4%. The amount of sedimentation obtained using the MUSLE method in 2019 was 6,869,98 tons and in 2009 was 41,692,97 tons. Erosion valuein 2019 is relatively small compared to other years. It’s really depends on the rainfall and the discharge that occurs. Therefore, a good land management system, proper and appropriate technology used, eco-hydrology concept and the monitoring of land use change regularly are needed, so damage that impact the Krueng Pase watershed can be prevented and minimize.

Download Full-text

KAJIAN EROSI LAHAN DI KAWASAN AIR STRIP RUNWAY 2600 BANDARA DEPATI AMIR (PGK) BERDASARKAN TATA GUNA LAHAN MASTERPLAN ULTIMATE

FROPIL (Forum Profesional Teknik Sipil) ◽

10.33019/fropil.v7i2.1627 ◽

2019 ◽

Vol 7 (2) ◽

pp. 100-111

Author(s):

Miskar Maini ◽

Junita Eka Susanti

Keyword(s):

Sediment Yield ◽

Soil Loss ◽

Universal Soil Loss Equation ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

Sediment Delivery ◽

Soil Loss Equation

Standar permintaan engineering pesawat agar desain bangunan infrastruktur di area Air Strip Runway 2600 yang ada dapat mempunyai fungsi lain. Sedangkan kondisi lain sangat menentukan keselamatan karena lahan di sekitar Air Strip Runway 2600 Bandara Depati Amir (PGK) jika tidak ditutupi vegetasi seperti rumput, kondisi lain lahan yang belum ditutupi vegetasi di sekitar Air Strip Runway 2600 berpotensi akan mengalami erosi lahan, kemudian hasil erosi lahan ini akan terbawa oleh aliran air sehingga akan masuk ke saluran drainase yang akan menyebabkan sedimentasi pada saluran drainase tersebut, akhirnya akan berkurang efektifitas kinerja saluran drainase tersebut. Metode yang digunakan untuk memprediksi laju rata-rata erosi di area Air Strip Runway 2600 dengan memperhitungkan faktor erosivitas hujan, erodibilitas tanah, kemiringan lereng atau panjang lereng, pengelolaan tanaman dan konservasi tanah, yang masing masing tata guna lahan tersebut mengacu pada Masterplan Ultimate Bandara Depati Amir (PGK). Perhitungan dilakukan menggunakan persamaan USLE (Universal Soil Loss Equation) yang dikembangkan oleh Wischmeier dan Smith (1965, 1978), kemudian Sediment Delivery Ratio (SDR) dan Sediment Yield.Hasil penelitian ini, prediksi laju erosi permukaan pada area Air Strip Runway 2600 Bandara Depati Amir (PGK) tahun pertama yang mencapai 5,60 mm/tahun atau 100,76 Ton/Ha/tahun, laju erosi tahun kedua mencapai 3,38 mm/tahun atau 60,84 Ton/Ha/tahun dapat diklasifikasikan ke dalam kelas bahaya erosi sedang (kelas III) dan nilai SDR adalah sebesar 56,3%, nilai sediment yield (SR) pada tahun pertama sebesar 5.887,59 Ton/Tahun, pada tahun kedua ketika rumput pada area Air Strip telah tumbuh dengan sempurna terjadi penurunan hasil sediment yield yaitu nilai SR sebesar 3.554,85 Ton/Tahun.

Download Full-text