模拟氮沉降对云冷杉红松林土壤呼吸的影响

Effects of Simulated Nitrogen Deposition on Soil Respiration in Spruce-fir-Korean Pine Forest of Xiaoxing'anling Mountains in China

2011年5月至2011年10月在黑龙江省小兴安岭云冷杉红松林内进行模拟氮沉降试验,使用便携式土壤CO2通量观测仪LI-8100测定不同氮沉降浓度CK(0)、TL(50 kg.hm-2.a-1)、TM(100 kg.hm-2.a-1)和TH(150 kg.hm-2.a-1)对土壤呼吸的影响。结果表明,氮沉降未显著改变土壤呼吸的日变化和季节性变化规律;对比CK,TL、TM和TH处理,分别使土壤日呼吸速率提高了13.72%、23.22%和5.12%,年呼吸速率提高了13.98%、18.26%和1.12%;土壤呼吸与温度呈极显著的指数相关(P<0.001),与土壤湿度无显著相关;CK,TL、TM和TH处理下,土壤呼吸温度敏感系数Q10分别为4.77、5.71、6.62和5.49,氮沉降处理提高了小兴安岭云冷杉红松林的土壤呼吸速率和温度敏感性。

In order to investigate the effects of simulated nitrogen deposition on soil respiration in spruce-fir-Korean pine forests, a simulated nitrogen deposition experiment was conducted in Xiaoxing＇ anling Mountains area in Hei- longjiang Province from May to October, 2011. The experiment included the Control （0, CK ）, low-N （50 kg · hm 2 ·a-1, TL） , medial-N （100 kg ·hm-2 · a-1 , TM） and high-N （150 kg · hm-2 · a-1 , TH） treatment level. The results showed that the nitrogen deposition did not change the daily and seasonal variation patterns of soil respi- ration. Compared to Control, the TL, TM, and TH treatments increased the soil daily average respiration rates by 13.72% , 23.22% and 5.12% , and 13.98% , 18.26% and 1.12% for soil annul average respiration rates. Signinicant exponential relationship was found between soil respiration rate and soil temperature, but no significant rela- tionship was found between the soil moisture and soil respiration rates. The Q10 （the respiratory flux at one tempera- ture over the flux at a temperature 10 ℃ lower） were 4. 77, 5.71, 6.62 and 5.49 for soil respiration of the CK, TL, TM, and THtreatments respectively. The findings suggested that nitrogen deposition could promote soil respira- tion, and increase soil respiration temperature sensitivity in spruce-fir-Korean pine forests.