Emissions of greenhouse gases and ammonia from a wheat site under intensive management affected by different fertilization practices

Greenhouse gas (GHG) and ammonia (NH3) emissions from wheat fields have been a serious challenge to agriculture and the environment. The integration of the use of inorganic N fertilizer, organic fertilizer, and crop residues and their environmental effects is needed under conventional tillage. In situ field experiments were established to evaluate the impact of different fertilization practices on soil greenhouse gas and ammonia emissions from a winter wheat field. A fertilizer experiment was performed from 24th October 2019 to 11th June 2020 in a winter wheat (Triticum aestivum L.) field in China with six fertilization treatments: (1) unfertilized control (UC); (2) recommended mineral fertilizer application of 200 kg ha-1 N (RF); (3) RF plus 15 t ha-1 of organic fertilizer (RFLO); (4) RF plus 30 t ha-1 of organic fertilizer (RFMO); (5) RF plus 45 t ha-1 of organic fertilizer (RFHO); and (6) traditional mineral fertilizer application of 300 kg ha-1 N (TF). The results showed that the RF plus organic fertilizer treatments increased the soil organic total carbon (TC) and nitrogen (TN) levels. Under long-term fertilization, the CO2 emissions from the RFLO, RFMO, and RFHO treatments were 18.3, 19.9, and 20.0 t ha-1, respectively, compared with those from the RF and TF treatments (13.2 and 16.0 t ha-1, respectively). In addition, the N2O emissions from the organic-inorganic fertilizer treatment were 7.6 kg ha-1 for the RFLO treatment, 12.4 kg ha-1 for the RFMO treatment, and 8.1 kg ha-1 for the RFHO treatment, which were higher than those from the RF and TF treatments (3.1 and 5.6 kg ha-1, respectively). The NH3 emissions from the RFLO, RFMO, and RFHO treatments (17.3, 26.2, and 22.4 kg ha-1, respectively) were lower than those from the RF (31.2 kg ha-1) and TF (49.7 kg ha-1) treatments under long-term fertilization. The methane emission potential of organic-inorganic fertilizer applications was 27.0% to 98.5% higher than a single application of inorganic fertilizer.