Mr JEONG GU LEE1, Mr SONG RAE CHO1, Ms HYEON JI SONG1, Ms HO GYEONG CHAE1, Dr PIL JOO KIM2
1Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, South Korea, 2Institute of Agriculture and Life Sciences, Gyeongsang National University, South Korea
Plastic film mulching (PFM) utilization is rapidly expanded in intensive farming fields. PFM is very effective to increase crop productivity via improving soil temperature and moisture conditions. However, since PFM can deplete soil organic carbon (SOC) stock and increase greenhouse gas (GHG) emission, the utilization of PFM is still debating. In this two year-field study, to determine the influence of PFM on global warming impact, PFM and no-mulching treatments were installed in maize cropping field under chemical and organic fertilizations. In organic fertilization plots, cover crop was cultivated during the fallow season, and the whole biomass was recycled as green manure before sequential maize seedling. Maize productivity and net global warming potential (GWP) were analyzed during cropping seasons. To estimate net GWP, two GHG (N₂O and CH₄) fluxes and SOC stock changes were determined. SOC stock changes were analyzed using net ecosystem carbon budget (NECB), which implies the difference between C input and C output. GHG intensity (GHGI) was calculated using net GWP per unit of grain yield. PFM significantly increased maize grain yields by 45-78% over no-mulching under the same fertilization, but it was more effective in organic fertilization than chemical, due to higher nutrient input. In contrast, PFM considerably increased seasonal N₂O and CH₄ emissions by 4-11 and 132-263 % over no-mulching under the same amendment, respectively. PFM depleted SOC stock 29-36 and 186-227% more in chemical and organic fertilization than no-mulching, respectively. Irrespective with fertilization and mulching background, net GWP was decided by SOC stock change, which covered 75-93% of net GWP. PFM differently influenced net GWP and GHGI between chemical and organic fertilizations. In chemical fertilization, PFM increased net GWP by approximately 30% over no-mulching, but decreased GHGI by 20-32%. However, in organic amendment, PFM highly increased net GWP and GHGI by 147-177% and 45-71% over no-mulching, respectively. Therefore, PFM in chemical fertilization system could be very powerful tool to decrease global warming impact via crop yield increase. However, in organic farming system, PFM should be carefully selected to increase crop yields, due to highly increased global warming impact.
Jeunggu lee has master’s degree and ph. Degree in soil science laboratory of gyeongsang national university.