Effects of Long-Term Use of Compost on N₂O and CO₂ Fluxes in Greenhouse Vegetable Systems

ABSTRACT

This study was based on a long-term field trial of three different greenhouse vegetable growing systems which were started in March 2002. Fertilizer nitrogen and organic carbon inputs in three treatments in the spring of 2015 were as follows: (1) conventional system (CON): cow manure and dry chicken manure composts (about 146 kg N ha⁻¹ and 1483 kg C ha⁻¹) and urea (about 525 kg N ha⁻¹); (2) low-input system (LOW): cow manure and dry chicken manure composts (about 325 kg N ha⁻¹ and 3160 kg C ha⁻¹) and urea (about 263 kg N ha⁻¹); and (3) organic system (ORG): cow manure and dry chicken manure composts (about 651 kg N ha⁻¹ and 5456 kg C ha⁻¹). N₂O and CO₂ fluxes were monitored in the growing season of 2015 (from March to August) using static chamber and gas chromatography techniques. Results showed that: (1) The N₂O and CO₂ fluxes in three treatments all reached their peaks within 4 days and 8 days after irrigation, respectively. N₂O emissions were positively correlated with soil temperature, soil water-filled pore space (WFPS), and NO₃⁻-N contents, while strong association between CO₂ emissions and soil temperature was observed. (2) Lower cumulative N₂O emission and direct emission factor (p < 0.05) were observed in ORG than that from LOW and CON. (3) No significant differences of cumulative CO₂ emissions were observed in three treatments, but CO₂ emissions proportion of fertilizer carbon inputs and soil organic carbon stock in ORG was significantly lower (p < 0.05).

Acknowledgments

The authors wish to thank Aiming Shi for managing the field experiment.

Funding

This work was supported by the National Science and Technology Pillar Program in rural areas (2013BAD20B01) and China Special Fund for Environmental Protection Research in the Public Interest (201309036).