秸秆还田和施氮对农田土壤呼吸的影响

2003年10月至2004年9月期间在华北平原冬小麦-玉米轮作的高产粮区开展了土壤温度、秸秆还田和施氮对农田土壤呼吸影响的研究。土壤类型是砂姜黑土。试验共设6个处理,分别是N 1、N 1 W、N 2 W、N 3 W N 1 W O和N 2 W M,其中N 1、N 2和N 3表示3个施氮水平(纯N计,下同),分别是200 kg hm-2、400 kg hm-2和600 kg hm-2,W表示小麦秸秆还田,M表示玉米秸秆的1/3还田,O表示施用有机肥(每年施用鸡粪30 m3hm-2)。土壤呼吸采用碱液吸收法测定,每个处理6次重复,结果表明:(1)土壤呼吸季节动态明显,夏季高冬季低,土壤呼吸排放速率与5cm深度地温线性拟合最好(R2=0.63~0.74,p<0.001),而与地表温度线性拟合最差。各处理土壤呼吸的年通量在5650~7061 kg.hm-2(纯C计,下同),随着秸秆还田量的增加,土壤呼吸通量显著增加(p=0.05),随着施氮量的增加土壤呼吸通量也增加,但只有施氮量相差400 kg hm-2时,土壤呼吸通量差异显著(p=0.05),施用有机肥的处理土壤呼吸通量最高,有机肥施用后1~2个月,有机肥快速分解,表现为高的土壤呼吸通量。由土壤呼吸与5cm深度地温指数拟合方程求得的Q10值在1.86~2.26之间。

The effects of crop residue amendment and N rate on soil respiration

This study was conducted to examine the effects of N fertilization and amendments of crop residue on soil respiration in a farm with winter wheat-maize rotation in the North China Plain during Oct.2003 ~ Sept.2004.Six treatments included N1,N1+W,N2+W,N3+W,N1+W+O,and N2+W+M,where N1,N2,and N3(Pure N,the same below) were 200,400,and 600 kg hm~(-2) a~(-1), respectively;W was the amendments of wheat residue;M was the amendments of maize residue;and O was 30 m~3 chicken manure hm~(-2) a~(-1).Soil respiration was...