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Recently, large areas of tropical peatland have been converted into agricultural fields. To be used for agricultural activities, peat soils need to be drained, limed and fertilized due to excess water, low nutrient content and high acidity. Water depth and amelioration have significant effects on greenhouse gas (GHG) production. Twenty-seven soil samples were collected from Jabiren, Central Kalimantan, Indonesia, in 2014 to examine the effect of water depth and amelioration on GHG emissions. Soil columns were formed in the peatland using polyvinyl chloride (PVC) pipe with a diameter of 21 cm and a length of 100 cm. The PVC pipe was inserted vertically into the soil to a depth of 100 cm and carefully pulled up with the soil inside after sealing the bottom. The treatments consisting of three static water depths (15, 35 and 55 cm from the soil surface) and three ameliorants (without ameliorant/control, biochar+compost and steel slag+compost) were arranged using a randomized block design with two factors and three replications. Fluxes of carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) from the soil columns were measured weekly. There was a linear relationship between water depth and CO 2 emissions. No significant difference was observed in the CH 4 emissions in response to water depth and amelioration. The ameliorations influenced the CO 2 and N 2 O emissions from the peat soil. The application of biochar+compost enhanced the CO 2 and N 2 O emissions but reduced the CH 4 emission. Moreover, the application of steel slag+compost increased the emissions of all three gases. The highest CO 2 and N 2 O emissions occurred in response to the biochar+compost treatment followed by the steel slag-compost treatment and without ameliorant. Soil pH, redox potential (Eh) and temperature influenced the CO 2 , CH 4 and N 2 O fluxes. Experiments for monitoring water depth and amelioration should be developed using peat soil as well as peat soil-crop systems.

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Rice is an essential crop in Indonesia. Any aspects of rice to increase productivity have been well studied and documented; however, there are still lacking well-documented studies on its environmental aspects, including climate change. Many researches might already be conducted, but only a few have been published in a peer-reviewed journal. There is still a lack of robust data on greenhouse gas (GHG) emissions from the rice field in Indonesia, factors affecting and the technology on how to reduce it. From the reviewed publications, it was found out that research only conducted under a controlled environmental setting. More research on understanding the controlling factors (e.g., water management, rice cultivar, soil types, and fertilizer) of GHG emission from rice field is still needed. The result will introduce a sustainable farming practice,  with low in GHG emissions, high in productivity, simple to apply and generate more income to farmers. This review has identified the gaps for future research and development in Indonesia. The research should meet the need, either national or global strategies. Development of a new farming practice will succeed in the presence of government policies. Therefore an intensive interdisciplinary approach between researcher and other stakeholders should be conducted.

ABSTRAKTanpa olah tanah (NT) telah banyak ditunjukkan sebagai praktik pengelolaan lahan sawah yang mampu mengurangi emisi gas rumah kaca (GRK) karena kemampuannya untuk menyerap karbon dalam tanah. Di luar negeri, bahkan juga oleh FAO, sekarang ini sedang banyak dikembangkan apa yang disebut dengan conservation agriculture, yaitu cara bercocok tanam dengan meminimalkan gangguan pada tanah atau dikenal juga dengan istilah No tillage/Zero Tillage (tanpa olah tanah). Penelitian ini bertujuan untuk memperoleh informasi emisi CH4 dan N2O dari lahan sawah di daerah tropis dengan perlakuan cara olah tanah. Percobaan disusun dengan rancangan faktorial acak kelompok 3 ulangan. Perlakuan yang dicobakan terdiri dari 2 faktor, yaitu faktor I cara olah tanah (1) Olah tanah sempurna, (2) tanpa olah tanah, dan faktor II adalah pemberian herbisida berupa (1) glifosat, (2) paraquat dan (3) tanpa herbisida. Jarak tanam adalah tegel 20 cm x 20 cm. Emisi CH4 pada MK 2015 yang terendah adalah pada perlakuan tanpa olah tanah (TOT) dan pemberian herbisida glifosat, yaitu sebesar 201 kg CH4/ha/musim dan yang tertinggi pada perlakuan olah tanah sempurna tanpa penambahan herbisida yaitu sebesar 353 kg CH4/ha/musim. Tanpa olah tanah menghasilkan rerata fluks harian CH4 yang lebih rendah dibanding perlakuan olah tanah sempurna. Emisi N2O terendah dihasilkan pada perlakuan olah tanah sempurna dengan penambahan herbisida glifosat, yaitu sebesar 0,34 kg N2O/ha/musim, dan tertinggi pada perlakuan tanpa olah tanah dengan penambahan herbisida paraquat yaitu sebesar 0,65 kg N2O/ha/musim. Hasil padi pada semua perlakuan menunjukkan nilai yang tidak berbeda nyata. Faktor emisi N2O langsung dari lahan padi sawah irigasi dengan perlakuan olah tanah dan herbisida berkisar antara 0,0008 -0,0015 kg N2O-N/kg N dengan kisaran hasil padi sebesar 4,96 -5,12 t/ha GKG. Secara total, yang dinyatakan dengan GWP, perlakuan tanpa olah tanah menimbulkan emisi GRK yang lebih kecil dibanding perlakuan olah tanah sempurna Kata kunci: olah tanah, herbisida, GWP, CH4, N2O ABSTRACTNo-tillage (NT) management has been promoted as a practice capable of offsetting greenhouse gas (GHG) emissions because of its ability to sequester carbon in soils. Even FAO and many countries, are now being widely developed what so called conservation agriculture, on how to grow crops with minimize soil disturbance or also known as No tillage/Zero tillage. This study aimed to obtain information CH4 and N2O emissions and grain yield from rice fields in the tropics with tillage treatments. The experiment was arranged in a randomized factorial design with 3 replications. The treatments tested consisted of two factors, namely the first factor was tillage (1) deep tillage, (2) zero tillage, and the second factor is application of herbicide in the form of (1) glyphosate, (2) paraquat and (3) without herbicides, using tiles row spacing (20 x 20 cm). In DS 2015, the lowest CH4 emissions resulted from no-tillage (TOT) treatment combined with the application of glyphosate, which amounted to 201 kg CH4/...