Pengaruh sedimen suspensi terhadap lingkungan tanah dan pertumbuhan biomassa tanaman kacang tanah di sekitar selokan Mataram

SUKARTONO, Gatot, Drs. H. Suratman Worosuprojo, MSc

2001 | Tesis | S2 Ilmu Lingkungan

Daerah Aliran Sungai (DAS) di Gunungapi Sumbing, Gunungapi Sindoro, Gunungapi Merbabu, dan Gunungapi Merapi mengalami erosi pada musim penghujan, airnya mengalir di Sungai Progo. Sebagiaii air tersebut dialirkan ke Selokan Mataram untuk dipergunakan mengairi lahan pertmian yang dinaunginya dan berakhir di Sungai Opak. Sedimen suspensi yang ada 1 Selokan Mataram ini mengendap di lahan yang terairi. Penelitian yang dilakdmi bermaksud mengetahui pengaruh massa tanah atasan dari DAS berupa sedimen suspensi terhadap lingkungan fisik yang dinaungi atau lahan yang terairi di bawahnya. Penelitian dilakukan di rumah kaca dengan menguji beberapa sampel tanah yang diambil di sekitar Selokan Mataram di Desa Tirtomartani, Kecamatan Kalasan, Kabupaten Sleman, Yogyakarta. Tolok ukur kesuburan tanah tersebut adalah pertumbuhan atau fabrikasi biomasa tanaman kacang tanah. Penelitian ini menggunakan Rancangan Acak Lengkap Dua Faktor yaitu jarak sampel tanah dari Selokan Mataram dan pupuk NPK, dan hasilnya dianalisis dengan Duncan's Multiple Range Test (DMRT). Tanah sampel dianalisis di laboratorium tanah. Hasil yang diperoleh yaitu jarak 30 meter memiliki nilai fabrikasi biomasa yang terbaik dan yang terendah yaitu tanah kontrol yang tidak mengandung sedimen suspensi Selokan Mataram. Kandungan fraksi lempung yang tinggi atau KPK tinggi pada tanah pasiran sangat menentukan dalam menjerab pup& NPK (tidak mudah tercuci), sehingga hara tanah mudah tersedia bagi tanaman dan mendukung fabrikasi biomasa tanaman dengan baik.

The erosion of catchment's area of Progo River (Sumbing, Sindoro, Merbabu, and Merapi Volcanoes) produce a lot of sediment that is transported through river water flows down to the downstream part. The river water is being used to irrigate the north part of Yogyakarta Province irrigation area through Mataram Irrigation Canal. The suspended sediment that flows with the irrigation water deposited in irrigated land. The aim of this research is to know the influence of the suspended sediment originated fiom the topsoil of the catchment area, to the physical environment and the fertility of irrigated land. This research is conducted in the green house over several samples taken from agriculture lands around Mataram Canal in Tirtomartani Village, Kalasan Sub District, Sleman District, Province of Yogyakarta. The criteria used in this research to judge the soil fertility is the growing rate or biomass fabrication of peanuts. The research used Completly Random Design for two factors that are the distance of the land from the Mataram Canal and the content of NPK fertilizer in soils. The results were analyzed with Duncan's Multiple Range Test. Soil properties (chemically and physically) were analyzed in soil laboratory. The results show that the best rate of biomass fabrication is found in the soil that is laid 30 m distance from the canal and the poorest is the control soil that has no suspended sediment content fiom Mataram Irrigation Canal. The high clay fraction content and high Cation Exchange Capacity (CEC) in the sandy soil could support the capability to hold the NPK fertilizer in the soil, it means that the natural fertility is easily available for the plants and support the biomass fabrication

Kata Kunci : Lingkungan Hidup,Sedimen Suspensi Tanah Selokan,Tanaman Kacang