|
| Nitrogen Losses of Zhaidi Underground River Agricultural System in Eastern Guilin |
| Received:April 17, 2015 |
| View Full Text View/Add Comment Download reader |
| KeyWord:Zhaidi underground river;N loss;nitrate;ammonia volatilization |
| Author Name | Affiliation | | XIE Yun-qiu | Key Laboratory of Karst Ecosystem and Rocky Desertification Rehabilitation, MLR & Institute of Karst Geology, CAGS, Guilin 541004, China | | YU Hong | The Third Middle School of Liuzhou, Liuzhou 545006, China | | PEI Jian-guo | Key Laboratory of Karst Ecosystem and Rocky Desertification Rehabilitation, MLR & Institute of Karst Geology, CAGS, Guilin 541004, China | | CHEN Yu | High School of Guigang, Guigang 537000, China |
|
| Hits: 2511 |
| Download times: 2363 |
| Abstract: |
| In order to evaluate non-point pollution of agriculture in karstic area, nitrogen losses via subterranean runoff, ammonia volatilization and farm product exports were estimated in Zhaidi karst underground river agricultural systems in Lijiang River watershed situated in Guilin City, Guangxi Zhuang Autonomous Region. Results showed that 1.03×105 kg of nitrogen was lost every year in Zhaidi karst underground river agricultural ecosystem. Of which 4.37 ×104 kg N was removed through soil and water loss of underground river, 3.91×104 kg N escaped by ammonia volatilization, and 2.06× 104 kg N output as farm products. Soluble N, with 99% of NO-3-N, amounted to 2.62×104 kg, 8 times more than 30 years ago. Sediment-adsorbed N was 1.75×104 kg. More than 90% of N losses via water and soil occurred in rainy days, which was mostly caused by chemical fertilizer N in the first half year and by the excreta of animal and human(including manure) or sewage mixed with dung in the second half year. Fresh peach fruits exported 39.8% of N outputs of agricultural produce. Rice field contributed to 56.5% of ammonia volatilization, which was caused by high pH of calcareous soil. Therefore, about 80% of lost N in Zhaidi karst underground river agricultural system entered into surface water and atmospheric environment through water-soluble and gaseous forms, increasing environmental pressure on the Lijiang River. |
|
|
|
