Dr Gilwon Kim1
1Western Sydney University, Hobartville, Australia
Excessive application of N fertilizer to rice results in water and atmospheric pollution including greenhouse gas (GHG) emissions. Therefore, N fertilizer management needs to be optimized taking into account grain yield, global warming potential (GWP, Mg CO2 eq. ha-1) and GHG intensity (GHGI, kg CO2 eq. kg-1 grain). However, the tradeoffs between the effects of N rate on rice grain yield, GWP and GHGI have not been adequately evaluated. Therefore, field experiments to determine the effect of N rate (as urea) on yield, GWP and GHGI were conducted in a typical flooded, transplanted rice paddy in a temperate environment. Methane (CH4) and nitrous oxide (N2O) emission rates were determined throughout the entire year (both during growing and fallow seasons) over two years. Rice grain yield showed a quadratic response to N rate, and the maximum yield (6.7-6.8 t ha-1) was achieved at 112-119 kg N ha-1, 50% higher than the yield of the control (0 kg N ha-1). Increasing N rate increased the seasonal N2O flux by 4.56-7.11 g N2O kg-1 N, but N2O flux contributed less than 7% of the total GWP. The GWP was mainly determined by the CH4 flux, which showed a relatively flat quadratic response to N rate, peaking at 124-138 kg N ha-1. Thus, GWP also showed a quadratic response to N rate, peaking at 122-130 kg N ha-1. The GHGI decreased as N rate increased and was the lowest (1.10-1.28 kg CO2-eq. kg-1 grain yield) at 104-112 kg N ha-1, approximately 20% lower than GHGI in the 0 N treatment. In conclusion, the N rate for maximum yield was similar to the N rate for minimum GHGI, mainly because of the small effect of N rate on CH4 emissions and the low magnitude of N2O emissions. Thus, GHGI was largely driven by grain yield, so the N rate for maximum grain yield was similar to the N rate for maximum GHGI. Proper N fertilization is essential in rice farming systems to increase crop productivity and reduce the global warming impact (GWP and GHGI).
Biography:
Gil Won Kim
Researcher
Hawkesbury Institute for the Environment (HIE)
Western Sydney University
E-mail: G.Kim@westernsydney.edu.au
Major Projects:
- How to reduce GHGs emission and increasing biomass productivities form pasture field
- The effect of N fertilization on carbon balance and GHGs emission in agricultural land
- Evaluation of CO2 emission factor from urea and calcium carbonate in agricultural land.
Scientific Publications (peer-reviewed paper)
- Jeong, S.T., Cho, S.R., Lee, J.G., Kim, P.J., Kim, G.W., 2019. Composting and compost application: Trade-off between greenhouse gas emission and soil carbon sequestration in whole rice cropping system. Journal of Cleaner Production 212: 1132-1142
- Cho, S.R., Jeong, S.T., Kim, G.Y., Lee, J.G., Kim, P.J., Kim. G.W., 2019. Evaluation of the carbon dioxide (CO2) emission factor from lime applied in temperate upland soil. Geoderma 337: 742-748
- Khan, M.I., Hwang, H.Y., Kim, G.W., Kim, P.J., Das, S., 2018. Microbial responses to temperature sensitivity of soil respiration in a dry fallow cover cropping and submerged rice mono-cropping system. Applied Soil Ecology 128: 98-108
- Jeong, S.T., Kim, G.W., Hwang, H.Y., Kim. P.J., Kim. S.Y., 2018. Beneficial effect of compost utilization on reducing greenhouse gas emissions in a rice cultivation system through the overall management chain. Science of The Total Environment 613: 115-122
- Kim, G.W., Alam, M.A., Lee, J.J, Kim, G.Y., Kim, P.J., Khan, M.I., 2017. Assessment of direct carbon dioxide emission factor from urea fertilizer in temperate upland soil during warm and cold cropping season. European Journal of Soil Biology 83: 76-83
- Kim, G.W., Gwon, H.S., Jeong, S.T., Kim, P.J., 2017. Influence of nitrogen fertilization on net ecosystem carbon budget in temperate mono-rice paddy. Geoderma 306: 58-66
- Hwang, H.Y., Kim, G.W., Kim, S.Y., Haque, M.M., Khan, M.I., Kim, P.J., 2017. Effect of cover cropping on the net global warming potential of rice paddy soil. Geoderma 292: 49-58.
- Kim, G.W., Das, S., Hwang, H.Y., Kim, P.J., 2017. Nitrous oxide emissions from soils amended by cover-crops and under plastic film mulching: Fluxes, emission factors and yield-scaled emissions. Atmospheric Environment 152: 377-388.
- Kim, G.W., Gwon, H.S., Jeong, S.T., Hwang, H.Y., Kim, P.J., 2016. Different responses of nitrogen fertilization on methane emission in rice plant included and excluded soils during cropping season. Agriculture Ecosystems & Environment 230: 162-168.
- Kim, G.W., Jeong, S.T., Kim, G.Y., Kim, P.J., Kim, S.Y., 2016. Evaluation of Carbon Dioxide Emission Factor from Urea during Rice Cropping Season: A Case Study in Korean Paddy Soil. Atmospheric Environment 139: 139-146.
- Haque, M.M., Kim, G.W., Kim, P.J., Kim, S.Y. 2016. Comparison of net global warming potential between continuous flooding and midseason drainage in monsoon region paddy during rice cropping. Field Crops Research 193: 133-142.
- Kim, G.W., Ho, A., Kim, P.J., Kim, S.Y. 2016. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover. Waste Management 55: 306-312
- Atulba, S.L., Gutierrez, J., Kim, G.W., Kim, S.Y., Khan, M.I., Lee, Y.B., Kim, P.J. 2015. Evaluation of rice root oxidizing potential using digital image analysis. Journal of the Korean Society for Applied Biological Chemistry 58: 463-471.
- Haque, M.M., Kim, S.Y., Kim, G.W., Kim, P.J. 2015. Optimization of removal and recycling ratio of cover crop biomass using carbon balance to sustain soil organic carbon stocks in a mono-rice paddy system. Agriculture, Ecosystems & Environment 207: 119-125.
- Hwang, H.Y., Kim, G.W., Lee, Y.B., Kim, P.J., Kim, S.Y. 2015. Improvement of the value of green manure via mixed hairy vetch and barley cultivation in temperate paddy soil. Field Crops Research 183: 138-146.
- Gutierrez, J., Atulba, S.L., Kim, G.W., Kim, P.J. 2014. Importance of rice root oxidation potential as a regulator of CH4 production under waterlogged conditions. Biology and Fertility of Soils 50: 861-868.