Abstract:
Objective In order to clarify the relationship between soil N2O emission and carbon source, the response of soil N2O emission to carbon addition under different water conditions was studied by indoor incubation experiment.
Method The experiment set up four different treatments of no carbon source (C0), glucose (C1), sucrose (C2), mannitol (C3) at 2 g kg−1 carbon content, and two water conditions of low moisture (W1) and high moisture (W2) were set. All treatments were treated with the same amount of nitrogen fertilizer and cultured at room temperature 25 ℃ for a week. Soil N2O flux, CO2 flux and soil inorganic nitrogen content of different treatments were measured. Through statistical analysis, the effects of exogenous carbon and different water treatments on N2O emission from brown red soil in southern Hubei were revealed.
Result Under different water conditions, the addition of exogenous carbon decreased the content of NO3--N and NH4 + -N in soil. The results showed that soil moisture significantly affected soil N2O emissions, and the emission of N2O in high-moisture treatment was higher than that in low-moisture treatment. Compared with the control, the cumulative emissions of soil N2O under low moisture conditions were increased by 352.15 times, 393.07 times and 93.94 times, respectively, with the addition of glucose, sucrose and mannitol. Under the conditions of high moisture, the cumulative emissions of soil N2O treated with glucose, sucrose and mannitol were increased by 1.92 times, 0.63 times and 1.88 times, respectively.
Conclusion Three kinds of exogenous carbon input significantly promoted the total amount of soil N2O emissions, the treatment added glucose has the highest N2O emission, and the soil N2O emissions under high moisture conditions are much higher than those in low water treatments.
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