DINAMIKA EMISI GAS DINITROGEN OKSIDA (N2O) DARI LAHAN SAWAH SYSTEM OF RICE INTENCIFICATION (SRI) DAN KONVENSIONAL DI KECAMATAN WATES

DIMAS HARIS RIFAI, Dr. Murtiningrum, STP., M.Eng; Rizki Mafukhah, STP., M.Sc

2018 | Skripsi | S1 TEKNIK PERTANIAN

Lahan sawah mengemisikan gas dinitrogen oksida (N2O) yang merupakan salah satu jenis gas rumah kaca melalui proses nitrifikasi dan denitrifikasi. Dinamika emisi gas dinitrogen oksida (N2O) dapat dipengaruhi oleh sistem budidaya padi metode SRI (System Of Rice Intensification) dan konvensional yang diterapkan pada lahan sawah. Penelitian ini bertujuan untuk menentukan sifat fisik tanah sawah, menganalisis besaran dan kecenderungan emisi gas N2O dari lahan sawah dan membandingkan emisi gas N2O yang dihasilkan oleh lahan sawah SRI dan konvensional di Kecamatan Wates. Penelitian ini dilakukan di Desa Ngestiharjo, Kecamatan Wates, Kabupaten Kulon Progo, DI Yogyakarta dengan menguji masing-masing variabel sifat fisik tanah dan menghitung fluks gas N2O yang diukur konsentrasinya dengan alat gas chromatography. Hasil penelitian menunjukan bahwa tanah sawah SRI dan konvensional di Kecamatan Wates memiliki sifat tekstur tanah yang sama yaitu clay. Nilai kadar lengas, porositas, berat jenis dan berat volume tanah sawah SRI berturut-turut adalah 16,47 %, 0,42, 1,62 g/cm3 dan 0,92 g/cm3. Nilai kadar lengas, porositas, berat jenis dan berat volume tanah sawah konvensional berturut-turut adalah 17,10 %, 0,48, 1,81 g/cm3 dan 0,93 g/cm3. Rata-rata emisi gas N2O dari lahan sawah SRI dan konvensional di Kecamatan Wates berturut-turut adalah 14,071 mikrogram/m2/h dan 32,216 mikrogram/m2/h. Sedangkan, tren emisi gas N2O pada lahan sawah SRI dan konvensional terlihat fluktuatif. Secara umum, perubahan emisi gas N2O pada lahan SRI dan konvensional di Kecamatan Wates memilki pola yang sama dengan rata-rata emisi gas N2O dari lahan sawah SRI lebih rendah 43,7 % daripada rata-rata emisi gas N2O dari lahan sawah konvensional.

Rice fields emit dinitrogen oxide (N2O) gas which is included as one of greenhouse gasses through nitrification and denitrification. Dynamics of dinitrogen oxide (N2O) gas emission could be affected by SRI (System of Rice Intensification) dan conventional management methods applied to the rice fields at Wates. This research aimed to determine physical characteristics of the soil, to analyze the amount and trend of N2O gas emission, and to compare N2O gas emitted by SRI and conventional rice fields at Wates. This research had been conducted in Ngestiharjo, Wates, Kulon Progo, DI Yogyakarta by examining each variable of physical characteristics of the soil and calculating the flux of N2O gas which concentration was measured with gas chromatography. The result of this research showed that SRI and conventional soil had the same texture characteristic which is clay. The moisture level, porosity, particle density and bulk density of SRI soil were 16,47 %, 0,42, 1,62 g/cm3 and 0,92 g/cm3 respectively while those of conventional soil were 17,10 %, 0,48, 1,81 g/cm3 and 0,93 g/cm3 respectively. The average amount of N2O gas emission from SRI and conventional rice fields at Wates were 14,071 mikrogram/m2/h and 32,216 mikrogram/m2/h respectively. Trend of N2O gas emission from SRI and conventional rice fields were fluctuative. In general, change of N2O gas emission from SRI and conventional rice fields had same pattern. The average amount of N2O gas emission from conventional rice field is 43,7 % lower than the average amount of N2O gas emission from SRI rice field.

Kata Kunci : nitrifikasi, denitrifikasi, fluks N2O, pengelolaan lahan metode SRI, pengelolaan lahan metode konvensional