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| Characteristics and main influencing factors of denitrification and ammonia volatilization in saline-sodic paddy soils |
| Received:March 30, 2023 Revised:May 09, 2023 |
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| KeyWord:saline-sodic soil;nitrogen;denitrification;ammonia volatilization;influencing factor |
| Author Name | Affiliation | | HUANG Lihua | Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
Jilin Da'an Farmland Ecosystem National Observation and Research Station, Da'an 131317, China | | YANG Yi | Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
College of Resources and Environmental, Jilin Agricultural University, Changchun 130118, China | | LIU Baishun | Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
Jilin Da'an Farmland Ecosystem National Observation and Research Station, Da'an 131317, China | | YANG Jingmin | College of Resources and Environmental, Jilin Agricultural University, Changchun 130118, China | | WANG Ping | Management Center of Jalaid National Modern Agricultural Industrial Park in Inner Mongolia Autonomous Region, Jalaid 137600, China | | HUANG Guangzhi | Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
Jilin Da'an Farmland Ecosystem National Observation and Research Station, Da'an 131317, China | | JIANG Xiaotong | Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
College of Resources and Environmental, Jilin Agricultural University, Changchun 130118, China |
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| Abstract: |
| Nitrogen loss caused by fertilization in farmland is an important source of environmental pollution. In order to clarify the effect of different degrees of soil salinization on nitrogen gas loss, 30 paddy soil samples with different degrees of salinization were randomly taken at 0-20 cm depth. According to the degree of salinization, the samples were divided into light(0.1%-0.3% salt content, 5%-15% exchangeable sodium percentage), moderate(0.3%-0.5% salt content, 15%-30% exchangeable sodium percentage), and severe(0.5%-0.7% salt content, 30%-45% exchangeable sodium percentage)saline-sodic soils. In each category, three soil samples with a similar degree of salinization were selected, according to the minimum number of classified samples(three replicates)for laboratory simulation culture analysis, in order to explore the dynamic characteristics of nitrogen denitrification and ammonia volatilization as well as their main influencing factors in soils with different degrees of salinization. The results showed that nitrogen denitrification decreased significantly, ammonia volatilization increased significantly, and the activities of nitrate reductase, nitrite reductase, and urease decreased significantly with increasing soil salinization(P＜0.05). The maximum denitrification rate and cumulative nitrogen denitrification in moderate and severe saline-sodic soil were 18.9% and 37.8%, 13.7% and 29.4% lower than those of light saline-sodic soil, respectively. The maximum ammonia volatilization rate and cumulative ammonia volatilization in moderate and severe saline-sodic soil were 30.8% and 64.8%, 36.6% and 59.4% higher than those of light saline-sodic soil, respectively. Stepwise regression analysis showed that EC, ESP(exchangeable sodium saturation percentage), CO32-, and TN were the main factors affecting cumulative nitrogen denitrification, while EC, CO32-, and SOM (soil organic matter)were the main factors affecting cumulative ammonia volatilization. Furthermore, higher Na+and CO32- content were the fundamental reasons for increased gaseous nitrogen loss in saline-sodic paddy fields. Although soil salinization inhibited nitrogen denitrification, it significantly enhanced ammonia volatilization, resulting in increased overall gaseous nitrogen loss and loss rate. |
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