Widyadmaja, Arya Putra (2019) Peran Akar Pohon untuk Pengendalian Tanah Longsor di DAS Mikro BangsriPeran Akar Pohon untuk Pengendalian Tanah Longsor di DAS Mikro Bangsri. Sarjana thesis, Universitas Brawijaya.
Abstract
Kualitas air sungai di DAS Bangsri Kecamatan Wajak menurun karena konsentrasi sedimen air sungai yang tinggi, yang berasal beberapa sumber antara lain erosi lahan pertanian, longsor dinding lahan dan dinding sungai dan dari kegiatan penambangan pasir; dengan demikian air sungai yang keruh tersebut kurang dapat dimanfaatkan oleh masyarakat. Salah satu strategi untuk mengurangi konsentrasi sedimen dalam air sungai adalah dengan meningkatkan stabilitas dinding lahan dan dinding sungai dengan cara menanam pepohonan di bantaran sungai yang bermanfaat bagi masyarakat, berperakaran dalam dan kuat. Kemampuan vegetasi dalam mencegah terjadinya longsor tergantung pada kerapatan dan jenis tanaman yang ditanam. Bagian terpenting dari tanaman untuk mencegah longsor adalah di bagian akar. Akar pohon dapat mengurangi longsor melalui 2 mekanisme yaitu (1) Mencengkeram tanah di lapisan permukaan (kedalaman 0-5 cm); (2) Menopang tegaknya batang sehingga menghambat terjadinya longsor. Penelitian dilaksanakan di Desa Bambang Kecamatan Wajak Kabupaten Malang yang termasuk dalam cakupan DAS Mikro Bangsri. Penelitian di lapangan berlangsung selama 1 bulan yaitu pada bulan April - Mei 2018. Analisis tanah dan tanaman dilaksanakan di Laboratorium Fisika dan Biologi Tanah Fakultas Pertanian Universitas Brawijaya. Penelitian ini dilakukan dengan melakukan survey akar pohon yang tumbuh di sepanjang sungai Bendo (riparian zone). Untuk parameter yang diamati ialah variabel pohon, meliputi diameter batang setinggi dada (dbh = diameter at breast height) yaitu diameter batang setinggi 1,3 m dari permukaan tanah dan kondisi perakaran. Kondisi perakaran yang diukur yaitu diameter akar horisontal dan vertikal, pola sebaran akar pohon. Varibel tanah meliputi tekstur, kadar air, berat isi, berat jenis, porositas dan pH tanah. Hasil penelitian menunjukkan bahwa ada 2 jenis pohon yang berpotensi untuk mengurangi resiko terjadinya longsor adalah pohon Mindi (Melia azedarach) dan pohon Suren (Toona surenii). Pohon mindi merupakan pohon penghasil kayu bangunan, adalah satu-satunya jenis tanaman yang memiliki nilai IJA dan ICA tinggi maka berpotensi besar sebagai penguat tebing, pohon rekisi dan pohon suren memiliki nilai IJA tinggi, tetapi nilai ICA tergolong sedang saja. Pada zona riparian DAS mikro Bangsri jenis-jenis pohon dengan nilai IJA tinggi, tetapi nilai ICA menurun, maka campuran beraneka macam pohon akan menghasilkan beraneka tingkat nilai IJA dan ICA yang ideal untuk meningkatkan stabilitas tebing lahan dan tebing sungai.
English Abstract
River water quality in the Bangsri watershed in Wajak sub-district has decreased due to high river water sediment concentrations, which originate from several sources including erosion of agricultural land, landslides and river walls and from sand mining activities; thus the murky river water cannot be utilized by the community. One strategy to reduce the concentration of sediment in river water is to increase the stability of land and river walls by planting trees on the riverbanks that are beneficial to the community, deep and strong. The ability of vegetation to prevent landslides depends on the density and type of plants planted. The most important part of the plant to prevent landslides is at the roots. Tree roots can reduce landslides through 2 mechanisms: (1) Gripping the soil in the surface layer (0-5 cm deep); (2) Support the upright of the stem so that it prevents landslides. The study was conducted in Bambang Village, Wajak District, Malang Regency which is included in the Bangsri Micro Watershed. The field research lasts for 1 month, from April to May 2018. Soil and plant analysis was carried out at the Soil Physics and Biology Laboratory, Faculty of Agriculture, Universitas Brawijaya. This research was conducted by surveying tree roots that grow along the Bendo river (riparian zone). The parameters observed were tree variables, including the diameter of the stem at breast height (dbh = diameter at breast height) ie the diameter of the stem as high as 1.3 m from the ground surface and the condition of the roots. Root conditions measured were horizontal and vertical root diameters, tree root distribution patterns. Soil variables include texture, moisture content, density, specific gravity, porosity and soil pH. The results showed that there are 2 types of trees that have the potential to reduce the risk of landslides, namely the Mindi tree (Melia azedarach) and the Suren tree (Toona surenii). Mindi tree is a wood-producing tree building, is the only type of plant that has a high value of IJA and ICA, so it has great potential as a reinforcement of cliffs, trees and suren trees have high IJA values, but the ICA value is classified as moderate. In the riparian zone of the Bangsri micro watershed, tree species with high IJA values, but the ICA value decreases, then a mixture of various kinds of trees will produce various levels of IJA and ICA values that are ideal for increasing the stability of land cliffs and river cliffs.
| Item Type: | Thesis (Sarjana) |
|---|---|
| Identification Number: | SKR/FP/2019/802/051909592 |
| Uncontrolled Keywords: | - |
| Subjects: | 600 Technology (Applied sciences) > 631 Specific techniques; apparatus, equipment materials > 631.8 Fertilizers, soil conditioners, growth regulators |
| Divisions: | Fakultas Pertanian > Agroekoteknologi |
| Depositing User: | soegeng sugeng |
| Date Deposited: | 10 Aug 2020 07:02 |
| Last Modified: | 19 May 2022 06:05 |
| URI: | http://repository.ub.ac.id/id/eprint/174737 |
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