LAND USE CHANGE: STUDIES ON CARBON AND NITROGEN DYNAMICS IN PARKING AREA, UPLAND, AND CHESTNUT ORCHARD FROM ORIGINALLY PADDY FIELD

PUTU OKI BIMANTARA, Dr. Ir. Eko Hanudin, M.P.; Dr. Weiguo Cheng

2017 | Skripsi | S1 ILMU TANAH

Alih fungsi lahan yang berbeda akan mempengaruhi dinamika karbon dan nitrogen di tanah. Penelitian ini bertujuan untuk mengetahui dinamika karbon dan nitrogen di tanah yang diperlakukan pada kondisi aerobik dan anaerobik. Sampel tanah diambil dari 3 jenis penggunaan lahan yang berbeda, yaitu lahan dataran tinggi (upland), perkebunan chestnut, dan areal parkir. Untuk kondisi anaerobic nilai dekomposisi bahan organik didapatkan berdasarkan produksi gas metan (CH4) dan produksi karbon dioksida (CO2). Untuk kondisi aerobik hanya berdasarkan oleh produksi karbon dioksida (CO2). Sedangkan untuk mineralisasi nitrogen di kondisi aerobik ditetapkan berdasarkan produksi amonium (NH4+) dan nitrat (NO3-), dan untuk kondisi anaerobik hanya berdasarkan produksi amonium (NH4+). Pada inkubasi aerobik, tanah di upland paling banyak memproduksi amonium (NH4+), 3 mg kg-1 di top soil dan 2.5 mg kg-1 di sub soil. Di tanah perkebunan chesnut terjadi nitrifikasi dan paling banyak terbentuk NO3- sekitar 2 mg kg-1 di top soil. Inkubasi tanah di areal parkir memiliki nilai mineralisasi yang rendah dikarenakan oleh nilai total nitrogen yang rendah (1.1 g kg-1 di top soil). Untuk nilai dekomposisi bahan organik pada inkubasi aerobik, perkebunan chestnut memiliki nilai yang hampir sama dengan tanah di upland, walaupun nilai karbon organik tanah di perkebunan chestnut lebih tinggi (21.1 g kg-1) dibanding nilai karbon organik tanah di upland (18.6 g kg-1), hal itu dikarenakan kandungan lignin yang tinggi di bahan organik di tanah perkebunan chestnut. Pada inkubasi dengan kondisi anaerobik, tanah di perkebuan chestnut memiliki nilai mineralisasi NH4+ (160 mg kg-1) dan dekomposisi bahan organik (5 g C/kg) tertinggi. Hanya tanah pada perkebuan chestnut yang diinkubasi secara aerobik, bakteri memproduksi gas metan oleh metanogenesis. Perbedaan tipe penggunaan lahan akan menghasilkan bahan organik, yang berbeda dan akan mempengaruhi dinamika karbon dan nitrogen di tanah.

Different type of land use change can affected dynamic of carbon and nitrogen in the soil. This research objective is to understand the dynamic of carbon and nitrogen in soil using aerobic and anaerobic condition. Soil samples were taken from 3 types of land use, such as upland, chestnut orchard, and parking area. For anaerobic condition the C decomposition potential was assessed based on methane (CH4) and carbon dioxide (CO2) produced, for aerobic condition the organic matter decomposition potential was assessed based only on carbon dioxide (CO2) produced. While the N mineralization for aerobic condition was determined from the potassium chloride (KCl)-extractable ammonium nitrogen (NH4+-N) and (NO3�N). For anaerobic condition only used ammonium nitrogen (NH4+-N). In aerobic soil incubation, the upland soil has the highest production of NH4+ about 3 mg kg-1 in top soil and 2.5 mg kg-1 in sub soil. In chestnut orchard the nitrification happened and has the highest production of NO3- about 2 mg kg-1 in the top soil. Parking area had low nitrification rates caused by low of total nitrogen value there is about 1.1 g kg-1 in top soil. For organic matter decomposition in aerobic soil incubation, the chestnut orchard soil had same similar amount with upland soil, even though the soil organic carbon in chestnut orchard had the higher value (21.1 g kg-1) compared to upland soil (18,6 g kg-1) it was caused by the high value of lignin. In anaerobic condition chestnut orchard soil had the highest nitrogen mineralization (160 mg kg-1) and organic matter decomposition (5 g kg-1). Only in chestnut orchard soil in anaerobic condition methanogenesis happened. It was the reason only in chestnut orchard produce CH4. Different type of land use will produces different type of organic matters that affected carbon and nitrogen dynamic in the soil.

Kata Kunci : C decomposition, N mineralization, Chestnut, Parking, Upland, Incubation