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Susilawati H.L.,Indonesian Agricultural Environment Research Institute | Susilawati H.L.,Chiba University | Setyanto P.,Indonesian Agricultural Environment Research Institute | Makarim A.K.,Indonesian Center for Food Crops Research and Development | And 3 more authors.
Soil Science and Plant Nutrition | Year: 2015

The increasing human population requires greater rice production. However, rice cultivation contributes to global warming through greenhouse gas (GHG) emissions. Technologies for reducing GHG emissions in concert with the increased rice production from rice fields are needed. The objectives of this study were to evaluate the effects of steel slag applications on methane (CH4) and nitrous oxide (N2O) emissions and rice yields. Two study sites were established at the experimental farm belonging to Indonesian Agricultural Environment Research Institute (IAERI) in Jakenan and a farmer’s field in Wedarijaksa sub-district, Indonesia. Both field trials were conducted during the dry season (DS) of 2009 and the rainy season (RS) of 2009/2010. During the DS, a randomized block design was arranged with two treatments (a control and a steel slag application at 1 Mg ha−1), which were replicated five times. During the RS, the experimental plot with 1 Mg ha−1 of steel slag treatment was split into two small sub-plots to accommodate the additional 1 and 2 Mg ha−1 steel slag treatments. The results showed that there was a decreasing tendency in the CH4 emissions at both sites and during both seasons after steel slag applications, although there was no statistical significance. During the RS in Jakenan, steel slag applications at rates of 1 and 2 Mg ha−1 decreased the CH4 emissions by 9.1 and 10.7%, respectively. In Wedarijaksa, steel slag applications at rates of 1 and 2 Mg ha−1 decreased the CH4 emissions by 12.6 to 18.7%, respectively. The N2O emissions were decreased by 34 and 38% following slag applications at the 2 Mg ha−1 rate during the RS in Jakenan and Wedarijaksa, respectively. The iron content of steel slag could be used to reduce not only CH4 but also N2O emissions. Increased level of electron acceptors suppresses CH4 and N2O emissions. The application of steel slag at 1 and 2 Mg ha−1 increased rice grain yields by approximately 4.8–5.6% in Jakenan and 0.3–4.7% in Wedarijaksa. It might be better to apply steel slag at higher rates for more than two growing seasons to reach reduction in CH4 and N2O emissions. © 2015 Japanese Society of Soil Science and Plant Nutrition.


Susilawati H.L.,Chiba University | Susilawati H.L.,Indonesian Agricultural Environment Research Institute | Setyanto P.,Indonesian Agricultural Environment Research Institute | Ariani M.,Indonesian Agricultural Environment Research Institute | And 2 more authors.
Soil Science and Plant Nutrition | Year: 2016

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 (CO2), methane (CH4) and nitrous oxide (N2O) from the soil columns were measured weekly. There was a linear relationship between water depth and CO2 emissions. No significant difference was observed in the CH4 emissions in response to water depth and amelioration. The ameliorations influenced the CO2 and N2O emissions from the peat soil. The application of biochar+compost enhanced the CO2 and N2O emissions but reduced the CH4 emission. Moreover, the application of steel slag+compost increased the emissions of all three gases. The highest CO2 and N2O 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 CO2, CH4 and N2O fluxes. Experiments for monitoring water depth and amelioration should be developed using peat soil as well as peat soil–crop systems. © 2015 Japanese Society of Soil Science and Plant Nutrition.


Hadi A.,Lambung Mangkurat University | Fatah L.,Lambung Mangkurat University | Affandi D.N.,Indonesian Agricultural Environment Research Institute | Bakar R.A.,University Putra Malaysia | Inubushi K.,Chiba University
Malaysian Journal of Soil Science | Year: 2012

Microbes are theoretically the driving force for the dynamics of greenhouse gases, especially nitrous oxide (N2O) and methane (CH4) which are trace gases but have high global warming potential (i.e., 23 and 296 times higher than that of CO2). Little is known about the population and genetic diversities of bacteria related to N2O and CH4 in peat soils, though an understanding of microbial aspects of N2O and CH4 may explain better the dynamics of these gases across wide ranges of peat conditions and human impacts. Conventional cultivation and molecular methods were carried out to determine the population and genetic diversities of N2O and CH4-related microbes in peat soils with different site locations and land-use covers. The results showed that the population of nitrifying bacteria varied with site locations and land-use covers and ranged from 0.33 x 103 MPN g-1 in an oil palm field in Wanaraya (KW site) to 4.43 x 103 MPN g-1 in a forest in Gambut (GH site). Similarly, the population of methanogenic bacteria was varied with site locations and land-use covers and ranged from 0.15 x 105 MPN g-1 in a paddy field in Barambai (BB site) to 34.46 x 105 MPN g-1 in a paddy field in Balangan (P site). The genetic diversity of denitrifying bacteria increased as forested peat lands (i.e., AH and GH sites) were converted to agriculture lands (other sites). The genetic diversity of nitrifying bacteria seemed to be site specific and less affected by land-use cover. Type I methanotrophic bacteria existed in forest in Gambut (GH site), but disappeared as the soils were cultivated for rice and applied with chopped-swamp weed or silicate fertiliser. The methanotropic bacteria type II existed in all sites and diversity was not affected by land-use cover or soil amelioration, suggesting that type II methanotrophic bacteria was less sentitive to environment shifts or human activities.

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