温度对太湖湖滨带不同水分梯度土壤氮矿化的影响

选择苏州渔阳山保存较为良好、典型的太湖湖滨带湿地作为试验地,并根据距离水体的远近,在湖滨带从近水体到高岗地分别设置3个实验区,每个实验区设置3个重复的取样点,将土样在实验室条件下,置于5、15、25和35℃人工气候箱中培养30 d,以测定土壤净氮矿化对温度的敏感性。结果表明:无论距离水岸带远近,湿地土壤的矿质氮含量、净氮硝化速率、净氮矿化速率总体趋势均表现为随温度的升高而增加;在相同温度下,距水体不同距离土壤的矿质氮含量、净氮硝化速率、净氮矿化速率变化总体趋势从小到大均表现为:近、中、远。土壤氮矿化速率变动范围为1.16～1.55,距离水体远近不同土壤的氮矿化速率增加倍数(Q10)没有明显的规律性。试验表明温度升高对湖滨湿地不同含水量土壤的氮矿化产生着不同的影响。

Responses of soil nitrogen mineralization to temperature along soil moisture gradients in the riparian zone of Taihu Lake

The soil net mineralized nitrogen amount and nitrogen mineralization rates along a soil moisture gradient in a riparian area in Taihu Lake were examined using random block experimental design and incubation method.The soil samples were put in PVC tube and incubated at 5,15,25,and 35 ℃,respectively for 30 days.The results showed that the soil mineralized nitrogen amount,net nitrogen nitrification rate and mineralization rates increased significantly with increasing temperature.At the same temperature,the soil mineralized nitrogen amount,net nitrogen nitrification rate and mineralization rates increased with distance from the water body.The Q10 value of soil nitrogen mineralization fluctuated between 1.16 and 1.55.There was no obvious regularity of the Q10 value of soil N mineralization with distance from the water body.The experiments showed that soil mineralization nitrogen in the riparian zone would be greatly influenced by soil temperature change.