Abstract
Soil dissolved organic carbon (DOC) plays a critical role in migration and transformation of soil organic carbon. For revealing effects of intercropping and N application on dynamics of DOC concentration and chemical structure, a multi-year located field experiment with cropping patterns (maize monocropping and maize-potato intercropping) subjected to four N levels (0 kg ha−1, 125 kg ha−1, 250 kg ha−1, 375 kg ha−1) was conducted. The results showed that N application raised DOC concentration while DOC accumulation, had a quadratic relationship with N application rate during the entire growth period of maize. At the same N level, intercropping increased the concentration and accumulation of DOC compared with monocropping. Meanwhile N application promoted the contents of amines and aromatic compounds and average molecular weight of DOC molecules, which reached the highest value at rate of 125 kg N ha-1. Compared with monocropping at the same N level, there was a tendency to increase the content of amines and aromatic compounds and the average molecular weight of DOC in intercropping, thus improving the degree of humification and aromatization of soil DOC. Soil temperature, water content and NH4+-N were the main factors mediating DOC concentration, while DOC concentration and soil temperature significantly affected the chemical structure of DOC. The structural equation model showed intercropping and N application elevated soil DOC concentration by increasing soil temperature, litter and root biomass, and the improvement of DOC concentration and soil temperature further enhanced the average molecular weight of DOC, resulting in accumulation of DOC.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.