Hubungan Curah Hujan Harian Terhadap Erosivitas di Kawasan DAS Brantas Hulu.

Akbariawan, Pradiktya Bagaskara (2019) Hubungan Curah Hujan Harian Terhadap Erosivitas di Kawasan DAS Brantas Hulu. Sarjana thesis, Universitas Brawijaya.

Abstract

Beberapa dekade terakhir telah terjadi perluasan lahan pertanian di DAS Brantas Hulu dengan cara alih guna lahan hutan atau kawasan alami menjadi lahan pertanian dan pemukiman. Hal tersebut mengakibatkan berkurangnya fungsi kanopi yang dapat berpotensi menyebabkan erosi ketika adanya hujan. Beberapa tahun terakhir, nilai erosi yang terjadi termasuk dalam skala sedang. Oleh karena itu perlu diketahui faktor penyebab terjadinya erosi. Beradasarkan metode USLE, salah satu faktor yang mempengaruhi erosi adalah curah hujan atau disebut erosivitas. Penelitian ini bertujuan mengetahui hubungan curah hujan terhadap erosivitas di kawasan DAS Brantas Hulu. Penelitian ini dilaksanakan pada bulan Januari hingga Mei 2017 di wilayah DAS Brantas Hulu dan Laboratorium Fisika dan Kimia Tanah, Fakultas Pertanian, Universitas Brawijaya. Wilayah penelitian berada di Desa Tulungrejo (6 plot) dan Desa Sumberejo (1 plot), Kecamatan Bumiaji, Kota Batu. Plot tersebut dipilih berdasarkan tutupan dan pengelolaan lahan. Tutupan dan pengelolaan lahan yang digunakan adalah hutan lindung, hutan produksi pinus, perkebunan apel, kentang pengelolaan gulud searah lereng, sawi pengelolaan gulud searah lereng, sawi pengelolaan teras, sawi pengelolaan gulud searah kontur. Ukuran plot yang digunakan 300 – 500 m2 untuk tutupan lahan tanaman semusim dan 500 – 1000 m2 untuk tutupan lahan tanaman tahunan. Parameter yang diambil di lapangan adalah curah hujan, sampel sedimen, struktur tanah, panjang dan kemiringan lereng, tutupan lahan dan pengelolaan lahan. Parameter yang dianalisis laboratorium adalah berat kering sedimen, tekstur tanah, permeabilitas tanah dan bahan organik. Analisis korelasi digunakan untuk mendapatkan hasil hubungan curah hujan dengan erosivitas di kawasan DAS Brantas Hulu. Selama 3 bulan penelitian, didapatkan sebanyak 33 hari hujan. Curah hujan tertinggi terdapat pada plot yang terletak pada wilayah yang tertinggi. Curah hujan antar wilayah penelitian juga beragam hasilnya, keberagaman antar wilayah tersebut disebabkan adanya perbedaan ketinggian pada lokasi penelitian sehingga mempengaruhi jenis hujan yang terjadi. Erosivitas tertinggi terdapat pada Sawi pengelolaan gulud searah kontur dan terendah terdapat pada hutan produksi pinus. Hubungan curah hujan dengan erosivitas yang dihasilkan dalam korelasi lemah (r ≤ 0,29), hal tersebut dikarenakan tidak konsistennya curah hujan terhadap erosivitas yang terjadi. Dimana, kenaikan curah hujan tidak diikuti dengan kenaikan erosivitas.

English Abstract

In the past few decades there has been an expansion of agricultural land in the Upper Brantas watershed by transferring forest land or natural areas into agricultural land and settlements. This results in reduced canopy function which can potentially cause erosion when it rains. In the past few years, the value of erosion that occurred has been on a medium scale. Therefore it is necessary to know the causes of erosion. Based on the USLE method, one of the factors that affect erosion is rainfall or erosion. This study aims to determine the relationship of rainfall to erosion in the Upper Brantas watershed. This research was conducted from January to May 2017 in the Upper Brantas watershed area and the Soil Physics and Chemistry Laboratory, Faculty of Agriculture, Universitas Brawijaya. The research area is in Tulungrejo Village (6 plots) and Sumberejo Village (1 plot), Bumiaji District, Batu City. The plot was chosen based on land cover and management. Cover and management of land used are protected forests, pine production forests, apple plantations, potato management of gulud in the direction of the slope, mustard management of gulud in the direction of the slope, mustard management of terraces, mustard management of gulud in the direction of contours. The size of the plot used is 300-500 m2 for annual crop cover and 500-1000 m2 for annual crop land cover. The parameters taken in the field are rainfall, sediment samples, soil structure, slope length and slope, land cover and land management. Parameters analyzed by the laboratory are sediment dry weight, soil texture, soil permeability and organic matter. Correlation analysis is used to obtain the results of the relationship between rainfall and erosion in the Upper Brantas watershed area. During the 3 months of the study, 33 rainy days were obtained. The highest rainfall is found in plots located in the highest area. Rainfall between research areas also varies in results, diversity between regions is due to differences in altitude at the study site, which affects the type of rain that occurs. The highest erosion is found in plots 7 and the lowest is found in plot 2. Erosion and influence factors of erosion affect the results of erosivity produced. The relationship of rainfall with erosivity produced is a weak correlation (r ≤ 0.29), so the relationship of rainfall in the Upper Brantas watershed to erosivity is weak.

Item Type: Thesis (Sarjana)
Identification Number: SKR/FP/2019/517/051907291
Uncontrolled Keywords: -
Subjects: 600 Technology (Applied sciences) > 631 Specific techniques; apparatus, equipment materials > 631.4 Soil science > 631.45 Soil erosion
Divisions: Fakultas Pertanian > Agroekoteknologi
Depositing User: soegeng sugeng
Date Deposited: 24 Aug 2020 07:18
Last Modified: 06 Dec 2021 02:41
URI: http://repository.ub.ac.id/id/eprint/173589
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