Effect of Fertilizer Management on Soil Carbon Dioxide Fluxes in Grassland and Cornfield during Winter

This study was conducted to investigate the effect of mineral (F) and Mineral-organic Fertilizers (MF) on soil CO۲ flux during winter in grassland and cornfield in Southern Hokkaido, Japan, from May ۲۰۱۳ to April ۲۰۱۴. CO۲ flux was measured by the static chamber method. Soil CO۲ concentration was determined using silicone tubes pipe. The environmental variables, i.e. climate and soil, were also analyzed in this study. Results showed that, in freezing period, CO۲ flux in MF was lower than F plots in grassland (۰.۱ and ۰.۴ Mg C ha-۱ period-۱, respectively). However, in melting period, CO۲ flux in F was lower than MF plots (۰.۰۱ and ۰.۱ Mg C ha-۱ period-۱, respectively).  CO۲ flux in F and MF plot was similar in cornfield in freezing (۰.۵ Mg C ha-۱ period-۱) and melting (۰.۰۱ Mg C ha-۱ period-۱). These results were opposite to the annual CO۲ flux where MF was higher than F plot in both grassland (۱۰.۹ and ۸.۵ Mg C ha-۱ period-۱, respectively) and cornfield (۸.۷ and ۶.۲ Mg C ha-۱ period-۱, respectively). Soil CO۲ concentration during winter was relatively higher in grassland than cornfield. Soil NH۴-N and Water Extractable Organic Carbon (WEOC) showed a positive correlation with soil CO۲ concentration   (r۲= ۰.۳۹ and r۲= ۰.۱۹, respectively). On the other hand, a negative correlation was observed between soil CO۲ concentration and soil NO۳-N content (r۲= -۰.۳۹).

کلیدواژه ها:

Carbon dioxide emission ، Green-house gasses ، Land use ، Manure ، Plant nutrient.