Chinese Journal of Agrometeorology ›› 2016, Vol. 37 ›› Issue (02): 121-130.doi: 10.3969/j.issn.1000-6362.2016.02.001

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Effects of Reducing Nitrogen and Biochar Application on CO2 and N2O Emissions from Summer Maize-Winter Wheat Field in North China

FAN Jing-wei,BAI Jin-hua,REN Huan-yu, HAN Xue, DIAO Tian-tian,GUO Li-ping   

  1. 1.Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agriculture Environment, Ministry of Agriculture, Beijing 100081, China;2.College of Forestry, Shanxi Agricultural University, Taigu 030801
  • Received:2015-06-19 Online:2016-04-20 Published:2016-04-18

Abstract:

This experiment was conducted in Xinxiang, Henan province from June 2013 to June 2014. Four treatments were designed including farmers common practice (F, 250kg·ha-1),80% F (LF, 200kg·ha-1),80% F + biochar(LFC) and no fertilizer (CK) to measure the dynamic emissions of CO2 and N2O from a summer maize-winter wheat field using static chamber and gas chromatography method. The results indicated that, (1)soil CO2 emission was 21.8-1022.7mg·m-2·h-1 for this agriculture system and was significantly influenced by soil temperature and moisture. Soil moisture was more important for the N2O emissions during the summer maize growth period while N2O emissions during winter wheat growth period was more significantly influenced by the soiltemperature. The cumulative CO2 emissions under LF and LFC treatments were significantly lower than F treatment especially during the winter wheat growing season. (2)Soil N2O emission was significantly influenced by fertilizer application and irrigation. N2O emissions during the fertilization period accounted for 73.9%-74.5% and 40.5%-43.6% of cumulative N2O emissions in summer maize and winter maize growing season, respectively. The peak of emission fluxes was primarily affected by fertilizer rate while irrigation determined the occurrence time when emissions would peak and could affect the mitigation effect of practices. Reduce the nitrogen application rate to 200kg·ha-1 from 250kg·ha-1 could decrease cumulative N2O emissions by 15.7%-16.8% and 18.1%-18.5% during summer maize and winter wheat growing seasons, respectively, therefore decreasing nitrogen application is an effective N2O mitigation practice for high-yielding and intensive farmland. Biochar application did not show no significant influence on soil N2O mitigation of biochar application at suitable nitrogen level(200kg·ha-1) in the short term. (3)N2O emission factors of applied nitrogen were 0.60% and 0.56% for F and LF treatment, respectively, indicating that reducing the nitrogen application rate is an appropriate measure to mitigate greenhouse gas emissions without impact on crop yields in intensive farmlands in North China.

Key words: Nitrogen reduction, Biochar, Greenhouse gases, N2O emissions, Winter wheat-summer maize