水肥减量对设施芹菜地N2O排放的影响

为明确减量灌溉和施肥对设施菜地N₂O排放的影响，提出有效的N2O减排措施，本研究采用静态箱法，对北京郊区设施芹菜在灌溉和有机肥（沼渣）减量处理下的N₂O排放进行全生长季监测，分析灌溉和有机肥减量对土壤充水孔隙度（WFPS）、NO₃--N和NH₄+-N含量及土壤N2O排放的影响。试验为2个灌溉量和3个有机肥施用量的裂区双因素设计，具体为：常规灌溉量（H处理）下的常规施肥(HN)、减量1/3施肥(HN₃)和不施肥 (HN0)，以及减量20%灌溉（L处理）下的常规施肥(LN)、减量1/3施肥(LN3)和不施肥 (LN0)共6个处理。结果表明，L处理在保证芹菜产量的前提下，对土壤充水孔隙度及无机氮含量无显著影响，但N₂O排放总量较H处理减少32.23%，达极显著水平（P＜0.01）。与常规施肥处理相比，减量1/3施肥和不施肥处理的土壤NO₃--N含量分别降低43.96%和76.42%，均达极显著水平（P＜0.01），不同施肥量处理间土壤NH₄+-N含量无显著差异；芹菜产量随施氮量增加而增加，但减量1/3施肥和常规施肥处理对芹菜产量影响无显著差异，芹菜全生长季的土壤累积N₂O排放总量显著减少62.04%（P＜0.01）。本试验条件下，减量20%灌溉（L处理）和减量1/3施肥（N3处理）均能保证芹菜产量，显著降低芹菜地N2O排放通量，减少生产成本投入。

Effects of Reducing Irrigation and Organic Fertilization on N2O Emissions from Celery Field in Facilities

In order to monitor the N2O emissions after irrigation and organic fertilization from vegetable soil in celery growing season, and make sure effective reduction measures were put forward, an experiment with 6 treatments was done in Beijing suburbs by using static chamber measurement techniques. The impact of the reductions of irrigation and organic fertilization (biogas residue) on the water-filled pore space (WFPS, 0-5cm), NO3--N content, NH4+-N content and N2O emissions were analyzed. It was a split block experiment with irrigation and fertilization two factors. The 6 treatments were as fellows: conventional irrigation under the condition of conventional fertilization (HN), conventional fertilization with 1/3 decrement (HN3) and no fertilization (HN0), and conventional irrigation with 20% decrement under the condition of conventional fertilization (LN), conventional fertilization with 1/3 decrement (LN3) and no fertilization (LN0). The results showed that, conventional irrigation with 20% decrement reduced total N2O emissions by 32.23%, significantly lower than that of conventional irrigation (P<0.01), however, had no significantly influence on celery yield, WFPS and Nmin content of soil. Compared with conventional fertilization, the treatments of conventional fertilization with 1/3 decrement and no fertilization had no significantly influence on NH4+-N content of soil, however, significantly reduced NO3--N content of soil (P<0.01) by 43.96% and 76.42%, respectively. In addition, conventional fertilization with 1/3 decrement made the cumulative N2O emissions from the soil in the whole growing season of celery, significantly reduced by 62.04%, however, had no significantly influence on celery yield. In this field experiment, conventional irrigation with 20% decrement (L) and conventional fertilization with 1/3 decrement (N3) both significantly reduced N2O emissions, and had no significantly influence on the celery yield, furthermore, the combination of the decrement of irrigation and fertilization (LN3) can reduce the production costs at the same time.