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| Effects of long-term fertilization on greenhouse gas and ammonia volatilization from vegetable fields in the Erhai watershed |
| Received:April 06, 2023 |
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| KeyWord:long-term positioning vegetable field;fertilization method;greenhouse gas;ammonia volatilization |
| Author Name | Affiliation | E-mail | | XU Zhuoying | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | XU Yongbo | College of Tobacco Science, Yunnan Agricultural University, Kunming 650201, China | xuyongboxx@163.com | | BAI Caihe | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | | | LEI Baokun | Yunnan Academy of Agricultural Sciences, Agricultural Resources and Environment, Kunming 650205, China | |
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| Abstract: |
| In this study, we sought to examine the trends and influencing factors of greenhouse gases（N2O, CH4, and CO2）and soil ammonia volatilization（NH3）in response to different fertilization modes an open vegetable field in the Erhai watershed under long-term fertilization. On the basis of a long-term positioning experiment conducted over 15 years, in 2007, we examined the characteristics of greenhouse gases and ammonia volatilization in response to the following five fertilization treatments：no fertilizer（CK）, organic fertilizer （OM）, chemical fertilizer and organic fertilizer（NPK+OM）, increased nitrogen fertilizer（NPK+OM+N）, and increased phosphate fertilizer （NPK+OM+P）. After 15 years of long-term positioning, the OM treatment was found to promote a significant increase in the contents of total nitrogen, organic matter, and available phosphorus in the vegetable field. Under iso-nitrogen conditions, compared with the OM treatment, treatment NPK+OM contributed to a significant increase in the NO - 3-N content of vegetable field soil. The pH of the soil subjected to the NPK+OM+N treatment was significantly lower than that of the NPK+OM treatment by 9.27%. Long-term incremental application of nitrogen fertilizer will lead to a significant reduction of soil pH, which leads to soil acidification. Application of organic fertilizer alone resulted in significant increases in soil CO2 and CH4 emissions. The accumulative emission of CO2 and CH4 in the OM treatment was found to be significantly higher than that in other treatments, with an accumulative emissions of（22 489.29±1 562.91）kg·hm-2 and（1.95±1.31）kg·hm-2, respectively. Furthermore, N2O emissions were significantly increased by increasing the application of nitrogen fertilizer. The cumulative N2O emission of NPK+OM+N was（38.33±10.74）kg·hm-2, which was significantly higher than that recorded for other treatments. Ammonia volatilization is mainly concentrated after topdressing. In this regard, we detected significant differences among the assessed treatments, which could be ordered as follows：NPK+OM+P>NPK+OM+N>NPK+OM. Compared with the NPK+OM treatment, treatments NPK+OM+P and NPK+OM+N promoted significant increases in NH3 emission by 245.7% and 124.3%, respectively. Unbalanced fertilization methods such as increased inputs of nitrogen and phosphorus fertilizers can contribute to significant increases in NH3 emission, and we detected significant increases in the global warming potential and greenhouse gas intensity in response to the application of organic fertilizer and nitrogen fertilizer alone. Single application of organic fertilizer led to the production of（3 183.81 ± 293.88）kg·hm-2 NH3. Although such fertilization can significantly increase vegetable yield, it also contributes to the largest global warming potential and greenhouse gas intensity. Total nitrogen, soil organic carbon, and pH are the key factors affecting the emission of greenhouse gases and ammonia volatilization. On the basis of the findings of this study, we recommend a fertilization scheme comprising the combined application of organic and chemical fertilizer, which can ensure economic benefits and also takes into account ecological and environmental factors. |
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