發(fā)布時間：2018-09-08 06:19

【摘要】：以我國小興安嶺地區(qū)涼水國家級自然保護區(qū)30年林齡的人工紅松林為研究對象,建立對照(0 kg hm~(-2)a~(-1))、低氮(20 kg hm~(-2)a~(-1))、中氮(40 kg hm~(-2)a~(-1))和高氮(80 kg hm~(-2)a~(-1))四種模擬氮沉降水平的樣地;采用室內培養(yǎng)試驗,研究了短期模擬氮沉降對人工紅松林土壤氮凈礦化、凈硝化速率和氧化亞氮排放的影響。結果表明,與對照處理相比,經過2年的模擬氮沉降處理,土壤的凈礦化、凈硝化速率都有降低趨勢。與對照相比,低氮、中氮、高氮土壤凈礦化速率分別降低了16.9%、20.6%和25.2%,土壤凈硝化速率分別降低了16.7%、20.9%和25.5%,但是處理間差異沒有達到顯著水平。凈硝化速率與凈礦化速率呈顯著正相關關系(P0.05),表明凈礦化速率降低減少銨態(tài)氮供應量可能是氮沉降處理降低凈硝化速率重要原因。另外,模擬氮沉降處理導致土壤p H降低也不利于硝化作用。中氮和高氮處理土壤氧化亞氮累積排放量分別比對照高84%和40%,但是差異不顯著。高的氮沉降量使硝化過程中氧化亞氮的排放比例增加,可能是中氮和高氮處理下凈硝化速率下降而土壤氧化亞氮排放量卻增加主要原因。研究結果表明,氮沉降會影響我國小興安嶺地區(qū)森林土壤氮礦化和硝化過程,但是由于實驗開展觀測時間較短,其影響規(guī)律還需長期實驗驗證。
[Abstract]:The artificial Pinus koraiensis forest in Liangshui National Nature Reserve of Xiaoxinganling region of China was used as the research object. Four simulated nitrogen deposition levels (40 kg hm~ (-2) a ~ (-1) and 80 kg hm~ (-2) a ~ (-1) in control (0 kg hm~ (-2) a ~ (-1),) low nitrogen (20 kg hm~ (-2) a ~ (-1),) were established. The effects of simulated nitrogen deposition on nitrogen net mineralization, nitrification rate and nitrous oxide emission in artificial Korean pine forest were studied in laboratory culture experiment. The results showed that the net mineralization and nitrification rate of the soil decreased after 2 years of simulated nitrogen deposition compared with the control treatment. Compared with the control, the net mineralization rate of low nitrogen, middle nitrogen and high nitrogen soils decreased by 16.9% and 25.2%, respectively, and the net nitrification rate of the soil decreased by 16.720. 9% and 25. 5%, respectively, but the difference between the treatments was not significant. There was a significant positive correlation between the net nitrification rate and the net mineralization rate (P0.05), which indicated that the decrease of the net mineralization rate and the reduction of the ammonium nitrogen supply might be the important reasons for the reduction of the net nitrification rate in the nitrogen deposition treatment. In addition, the reduction of pH in soil caused by simulated nitrogen deposition was not conducive to nitrification. The cumulative nitrous oxide emissions of medium and high nitrogen treatments were 84% and 40% higher than that of the control, respectively, but the difference was not significant. The ratio of nitrous oxide emission increased by high nitrogen deposition, which may be the main reason for the decrease of net nitrification rate and the increase of soil nitrous oxide emission under medium and high nitrogen treatments. The results show that nitrogen deposition will affect the process of nitrogen mineralization and nitrification in forest soil in Xiaoxinganling area of China, but the effect of nitrogen deposition on nitrogen mineralization and nitrification in the forest soil of Xiaoxinganling area of China needs to be verified for a long time due to the short observation time.
【作者單位】： 虛擬地理環(huán)境教育部重點實驗室(南京師范大學);江蘇省地理環(huán)境演化國家重點實驗室培育建設點;江蘇省地理信息資源開發(fā)與利用協(xié)同創(chuàng)新中心;
【基金】：江蘇高校優(yōu)勢學科建設工程資助項目(164320H116)資助
【分類號】：S714

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