The combined effects of nitrification inhibitor and biochar incorporation on yield-scaled Nsub2/subO emissions from an intensively managed vegetable field in southeastern China

摘要

An experiment was conducted to study the influences of nitrificationinhibitor (NI) and biochar incorporation on yield-scaled N₂O using thestatic chamber method and gas chromatography in an intensively managedvegetable field with seven consecutive vegetable crops from 2012 to 2014 insoutheastern China. With an equal annual nitrogen (N) applicationrate (1217 kg N ha-1 yr-1), six treatments under three biocharamendment rates – namely, 0 t ha-1 (C0), 20 t ha-1(C1) and 40 t ha-1 (C2) – with compound fertilizer (CF) or ureamixed with NI of nitrapyrin as chlorinated pyridine (CP) were studied inthese field experiments. The results showed that, although there was no significantinfluence on soil organic carbon (SOC) content or total nitrogen (TN),nitrapyrin could result in a significant increase in soil pH during theexperimental period. Nitrapyrin significantly decreased cumulative N₂Oemissions by 15.9–32.1% while increasing vegetable yield by9.8–41.9%. Thus, it also decreased yield-scaled N₂O emissionssignificantly. In addition to the differential responses of the soil pH,biochar amendment significantly increased SOC and TN. Compared with thetreatments without biochar addition, the cumulative N₂O emissions showedno significant difference in the CF or the CP group treatments but increasedslightly (not significantly) by 7.9–18.3% in the CP group treatments.Vegetable yield was enhanced by 7.1–49.5% in the CF group treatmentscompared with the treatments without biochar amendment, while there was nosignificant difference in the CP group treatments, and the yield-scaled N₂Oemissions were thus decreased significantly. Furthermore, treatmentsinvolving with nitrapyrin and biochar incorporation slightly increased yield-scaledN₂O emissions by 9.4%, on average, compared with CP-C0. Therefore,the application of nitrapyrin could serve as an appropriate practice forincreasing vegetable yield and mitigating N₂O emissions in intensivelymanaged vegetable fields and should be further examined in variousagroecosystems.