三江平原典型小叶章湿地土壤氨挥发特征及影响因素

Characteristics of ammonia(NH_3) volatilization and its affecting factors of typical Calamagrostis angustifolia wetland soils in Sanjiang Plain

采用通气法对三江平原典型草甸小叶章湿地和沼泽化草甸小叶章湿地土壤的氨挥发进行了原位测定,并对其主要影响因素进行了分析。结果表明,二者的氨挥发速率在生长季内的变化趋势基本一致,7月中旬前出现两次挥发高峰和一次低值,之后整体呈严格单调下降趋势,后者的氨挥发速率较高,平均为前者的1.35±0.53倍;二者累计氨挥发量的变化趋势也基本一致,7月中旬前增加迅速,且值比较接近;之后增加缓慢,但其值发生明显分异,表现为后者大于前者;生长季内,典型草甸小叶章湿地土壤的氨挥发总量为6.35 kg N.hm-2,而沼泽化草甸小叶章湿地则为6.87 kg N.hm-2,二者之比为1∶1.08;氮素物质基础不是影响二者氨挥发过程的重要限制因素,大气温度及其所引起的其它温度波动是影响氨挥发速率变化的重要因素;降水及土壤水分波动与散失是引起氨挥发速率局部波动的重要原因;土壤pH和质地是导致氨挥发速率普遍较低的根本原因;而各种因素综合作用的结果则是引起二者氨挥发速率和氨挥发量变化及差异的主要原因。

With venting method,this paper determined in situ the ammonia(NH_3) volatilization from the soils of typical meadow Calamagrostis angustifolia wetland and marsh meadow C.angustifolia wetland in Sanjiang Plain,and analyzed its main affecting factors.The results showed that the change trends of the NH_3 volatilization rates of these two typical C.angustifolia wetland soils were basically the same,with two peaks and a valley before the middle ten days of July,and as a whole,strictly monotony downtrend afterwar...