Soil Respiration and Nitrification-Denitrification in Intercropping System.

In an experimental field with maize/soybean intercropping, soil respiration, nitrification and denitrification in the intercropping system with two nitrogen treatments (N0-0 kg N ha^-1and N1-112.5 kg N ha^-1)was investigated using the barometric process separation (BaPS) method. Results indicated that root mass density in the rhizosphere in N1 was greater than that in N0. There was no significant difference in root mass density in the non-rhizosphere between two nitrogen treatments. Soil respiration rate in the rhizosphere in N1 was 1.1 times that in N0, while the difference in soil respiration in the non-rhizosphere between two N treatments was not significant. Soil nitrification rate in maize and soybean strips in N1 was 1.71 and 1.82 times that in N0, respectively. For two N treatments, soil nitrification in the rhizosphere was greater than that in the non-rhizosphere in intercropping, mainly because of the difference in root density. Soil denitrification rate was only measured in the late growth stage, indicating that denitrification was not the main way of nitrogen losses in maize/soybean intercropping in the experimental site. Results indicated that soil nitrification was the main way of N₂O emission in intercropped filed in the experimental zone.