KANDUNGAN BAHAN ORGANIK TANAH DAN POPULASI BAKTERI AMONIFIKASI PADA TIGA FISIOGNOMI DI HUTAN WANAGAMA I, GUNUNG KIDUL, YOGYAKARTA

TOFIQ BAYU SUTRISNA, Handojo Hadi Nurjanto, Haryono Supriyo

2010 | Skripsi | S1 KEHUTANAN

Lahan di Wanagama I merupakan contoh lahan kritis di Yogyakarta. Berbagai jenis tanaman telah ditanam di Wanagama I pada tahun 1968, yang dalam perkembangannya menjadi berbagai fisiognomi. Fisiognomi adalah kenampakan luar dari suatu lahan yang dapat diketahui dari penutupan lahan, pertumbuhan dan persebaran vegetasinya. Pada lahan kritis seperti di Wanagama I, kandungan bahan organik tanahnya relatif rendah yang berakibat pada rendahnya populasi mikroorganisme tanah dan ketersediaan unsur hara makro khususnya Nitrogen (N) yang sangat dibutuhkan oleh tanaman. Penelitian ini bertujuan untuk mengetahui kandungan bahan organik tanah dan populasi bakteri amonifikasi pada 3 fisiognomi di hutan Wanagama I. Penelitian ini dilakukan di Wanagama I, Laboratorium Fisiologi Pohon dan Laboratorium Tanah Hutan, Fakultas Kehutanan, Universitas Gadjah Mada. Pengambilan sampel tanah dilakukan di Fisiognomi 1 (Petak 7), Fisiognomi 2 (Petak 16), dan Fisiognomi 3 (Petak 5) hutan Wanagama I, Gunung Kidul, Yogyakarta. Pengambilan sampel tanah dilakukan pada kedalaman tanah 0-5 cm dan 10-15 cm. Pengujian sampel dilakukan dengan menggunakan metode Plate Count untuk bakteri total, metode Most Portable Number untuk bakteri amonifikasi, metode Walkley dan Black untuk bahan organik tanah, dan metode Kjeldahl untuk N total tanah. Kondisi lingkungan (suhu lingkungan, suhu tanah, kelembaban dan intensitas cahaya) diamati sebagai data pendukung. Hasil penelitian menunjukkan bahwa kandungan bahan organik tertinggi terdapat pada Fisiognomi 2. Kandungan bahan organik tanah pada musim kemarau lebih tinggi daripada musim hujan. Kandungan bahan organik tanah pada kedalaman tanah 0-5 cm lebih tinggi daripada kedalaman tanah 10-15 cm, Kelimpahan bakteri amonifikasi pada musim hujan lebih tinggi daripada musim kemarau.

Land in Wanagama I is a type of critical land in Yogyakarta. Various plants have been planted in Wanagama I in 1968, that developed into various physiognomies. Physiognomi is a physical appeareance of a certain landscape that is characterized by land cover, vegetation growth and distribution. The soil organic matter in the critical land Wanagama I was low because of low microorganism population and macro nutrient availability especially nitrogen (N) that needed by the plants. The aim of the research are to assess the content of soil organic matter and population of ammonification bacteria on 3 physiognomi in Wanagama I forest. This research was conducted in Wanagama I, Laboratory of Tree Physiology and Laboratory of Forest Soil, Faculty of Forestry, Universitas Gadjah Mada. Soil samples were taken in the Physiognomi 1 (Compartment 7), Physiognomi 2 (Compartment 16), and Physiognomi 3 (Compartment 5). Soil samples were taken in the depth of soil in the range of 0-5 and 10-15 cm. The test of sample used plate count method for the total bacteria, Most Probable Number (MPN) method for ammonification bacteria, Walkley and Black method for soil organic matter and Kjeldahl method for total amount of N soil. Environtment condition (temperature, soil temperature, moisture, and light intensity) have been taken as supporting data. The result showed of this research showed that the highest content of the soil organic matter was in the Physiognomi 2. The content of soil organic matter in dry season was higher than in rainy season. The content of soil organic matter in the depth of soil range of 0-5 cm was higher than the range of 10-15 cm. The abundance of ammonification bacteria in rainy season was higher than dry season.

Kata Kunci : Bahan organik tanah, bakteri amonifikasi, fisiognomi.