Effects of Nitrogen Application Rates on Rhizosphere Soil Enzyme Activity and Potential Nitrification in Maize and Potato Intercropping

Field trials were carried out to investigate the effects of different nitrogen application rates(0, 125, 250 and 375 kg/hm2) on rhizosphere soil enzyme activity and potential nitrification in maize//potato intercropping ecosystem. The results indicated that compared with monocropping, intercropping increased the activity of urease, protease and catalase, and promoted the soil nitrification. The enzyme activities and the potential nitrification in rhizosphere soil of maize and potato in intercropping increased with the increase of nitrogen application rates and peaked at N3 treatment, and the protease, catalase activities increased with the increase of nitrogen application rate and the highest increment was with N2 treatment at the jointing stage(squaring stage); the urease, protease, catalase activities in rhizosphere soil of maize and potato in intercropping increased with the increase of nitrogen application rate and peaked at N2 treatment, the potential nitrification increased with the increase of nitrogen application rate and the highest increment was with N3 treatment at the maturing stage. The result of correlation analysis revealed that the soil enzyme activity was significantly and markedly significantly related to soil potential nitrification. It is indicated that applying N and intercropping have a positive effect on the improvement of the soil enzyme activities and soil potential nitrification.