Emissions of greenhouse gas and ammonia from an intensive wheat site affected by different fertilization practices

Abstract

<b><sc>Abstract.</sc> Winter wheat (Triticum aestivum L) is an important crop grown for food in China. Minimizing soil greenhouse gas (GHGs) and ammonia (NH₃) emission has significant implications in regional air quality and nitrogen nutrient management from an intensive wheat site. Therefore, information on integrated use of inorganic N fertilizer, organic fertilizer, and crop residue, and their environmental effects is needed under Conventional Tillage. The objective of this work was to evaluate the effect of different fertilization practices on soil greenhouse gas and ammonia emissions from a winter wheat field. The field trial was set up in June 2015. The research was based on six fertilization treatments: 1) unfertilized control (UC); 2) recommended mineral fertilizers application of 200 kg·ha^−1 N (RF); 3) RF plus organic fertilizer of 15 t·ha^−1 (RFLO); 4) RF plus organic fertilizer 30 t·ha^−1 (RFMO); 5) RF plus organic fertilizer of 45 t·ha^−1 (RFHO); 6) traditional mineral fertilizers applications of 300 kg·ha^−1 N (TF). During growth season from 2019-2020, soil GHGs emission following N fertilization was measured using the closed static chambers method whereas NH₃ emissions were by passive adsorption method. The results showed that RF plus organic fertilizer treatments use helps increase soil organic Total carbon (TC) and nitrogen (TN) levels. In the long-term fertilization, the CO₂ emission for the RFLO, RFMO, and RFHO treatment were 18.3, 19.9, and 20.0 t·ha^-1, respectively, which were higher than for the RF and TF treatment (13.2 and 16.0 t·ha^-1, respectively). In addition, under long-term experiments, the nitrous oxide (N₂O) emission for the combined applications of organic fertilizer and RF treatment were 7.6 kg·ha^-1 for the RFLO, 12.4 kg·ha^-1 for the RFMO, and 8.1 kg·ha^-1 for the RFHO, respectively, which were higher than for the RF and TF treatment (3.1 and 5.6 kg·ha^-1, respectively). The NH₃ emission for RFLO, RFMO, and RFHO treatments (17.3, 26.2, and 22.4 kg·ha^-1, respectively) were lower than RF (31.2 kg·ha^-1) and TF (49.7 kg·ha^-1) treatment in the long fertilization treatments. CH₄ emissions were ignored in this study. Overall, the application of organic fertilizer can significantly decrease NH₃-N loss compared to mineral N application. However, CO₂ and N₂O emissions due to organic fertilizer application were higher than with the application of mineral N with long-term fertilization. </b>