Erodibilitas tanah dibawah tegakan bambu sepanjang tebing sungai Pesing kabupaten Bantul

Marita Putri Pambudiningsih, Dr. Muh Aris Marfai, S.Si., M.Sc.

2009 | Skripsi | S1 GEOGRAFI DAN ILMU LINGKUNGAN

Bambu merupakan tanaman yang penting di Indonesia. Berbagai macam penelitian tentang bambu telah banyak dilakukan. Namun kajian mengenai fungsi bambu dalam upaya memperkecil laju erosi khususnya erodibilitas tanah relatif masih terbatas. Bahkan penelitian tentang erodibilitas tanah di bawah tegakan bambu di sepanjang tebing Sungai Pesing belum pernah dilakukan. Studi ini didasarkan untuk mengetahui pengaruh tegakan bambu terhadap erodibilitas tanah di sepanjang tebing Sungai Pesing berdasarkan variasi jenis tanah. Penelitian ini dilaksanakan dengan pengamatan di lapangan, yang dilengkapi dengan pengambilan sampel tanah. Sampel tanah diambil dengan teknik purposive sampling berdasarkan perbedaan jenis tanah. Setiap jenis tanah, sampel diambil secara komposit, yaitu di bawah tegakan bambu maupun pada lahan kosong. Sampel tanah yang diambil merupakan tanah pada lapisan top soil. Analisis sifat tanah dilakukan di laboratorium, sedangkan indeks erodibilitas tanah (K) ditentukan dengan persamaan USLE yaitu menggunakan rumus Wischmeir. Parameter yang harus ditentukan untuk menentukan indeks erodibilitas adalah tekstur tanah, permeabilitas tanah, bahan organik dan struktur tanah. Hasil penelitian menunjukkan bahwa tegakan bambu dapat meningkatkan kandungan bahan organik, mempercepat permeabilitas tanah dan menghasilkan tekstur tanah menjadi lebih halus. Akar merupakan faktor yang mempengaruhi besarnya parameter erodibilitas tanah di bawah tegakan bambu. Hasil penelitian menunjukkan bahwa erodibilitas tanah di bawah tegakan bambu lebih rendah daripada lahan kosong pada semua jenis tanah di sepanjang tebing Sungai Pesing. Tegakan bambu dapat menurunkan indeks erodibilitas tanah pada lahan kosong. Sehingga tegakan bambu dapat digunakan sebagai tanaman konservasi secara vegetatif untuk mengatasi masalah erosi dan longsor di sepanjang tebing Sungai Pesing.

Bamboo is one of important plant in Indonesia. There are many kind researches of bamboo had been done. However, study about bamboo due to minimize soil erosion, especially the soil erodibility under stand of bamboos relatively rare. Moreover, the research of the soil erodibility under stand of bamboos alongside of Riverbank in Pesing River hadn't been conducted. This research was carried out to examine the influence stand of bamboos towards soil erodibility alongside of riverbank in Pesing River based on variation of soil types. This research was done with observation in field, completed with taking soil samples. It was taken by purposive sampling technique based on variation of soil types. Each sample of every soil types were taken compositely from top soil layer, under stand of bamboos and bare lands. Soil character analysis was done in laboratorium, while soil erodibility index was determined with USLE equation using Wischmeir equation. Determinant parameters to determine the erodibility index are soil texture, soil permeability, organics, and soil structure. Result of this research shows that stand of bamboos can increase organic contains, quicken soil permeability and to change soil texture to be softer. Roots are factors that influence in large soil erodibility parameters under stands of bamboos. The result also shows that soil erodibility under stand of bamboos is lower than in bare land for all soil types alongside of riverbank in Pesing river. Stand of bamboos can decrease soil erodibility index in bare land. So, stand of bamboos can be used as conservation plants to overcome erosion and landslide problems alongside of riverbank in Pesing river.

Kata Kunci : Erodibilitas Tanah,Tanah, Erodibilitas, Tegakan Bambu, Sungai