Integrating Ecological Restoration of Agricultural Non-Point Source Pollution in Poyang Lake Basin in China

Shuo Cai,Hengwang Xie,Hong Shi,Fangping Liu,Yuanlai Cui,Xiaohua Pan

doi:10.3390/w9100745

Shuo Cai, Hengwang Xie + Show 4 more

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https://doi.org/10.3390/w9100745

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Journal: Water	Publication Date: Sep 29, 2017
Citations: 26	License type: CC BY 4.0

Affiliation: Jiangxi Agricultural University, Wuhan University

Abstract

This study addresses the excessive consumption of river basin water from the Poyang Lake area in China. Consumption of water for irrigation, together with the discharge of agricultural non-point source pollution, is seriously affecting the water quality of Poyang Lake. This study assesses the application of integrated ecological restoration technology for agricultural non-point source pollution in the Ganfu Plain Area, which is an important agricultural production base in the Poyang Lake basin. The results indicated that the water-fertilizer comprehensive regulation mode for double-cropping rice provided water savings of 10.4% and increased rice yield by 6.5% per hectare. Furthermore, it reduced drainage water pollution by 20.4%, and emissions of ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), total phosphorus (TP), and total nitrogen (TN) from rice paddy surfaces by 18.6%, 11.1%, 15.4%, and 16.0%, respectively. The eco-channel–pond wetland system effectively reduced TN and TP pollutant levels in rice paddy drainage water; the eco-channel reduced TN and TP by 9.3% and 14.0%, respectively; and the pond wetland system showed reductions of 8.6% and 22.9%, respectively. The “three lines of defense” purification technology, including rice field source control, eco-channel interception, and pond wetland purification, removed 29.9% of TN and 44.3% of TP.

Highlights

Poyang Lake (28◦ 220 to 29◦ 450 N and 115◦ 470 to 116◦ 450 E), located downstream of the YangtzeRiver in the northern region of Jiangxi Province, is the largest freshwater lake in China, regulating a yearly average of 145 billion m3 of water and constituting approximately 15.6% of the runoff channeled into the Yangtze River [1,2]
Practical application results showed that, compared with the traditional method of water-fertilizer regulation technique, the rice paddy water-fertilizer comprehensive regulation technique conserved a total of 684.27 m3 /ha irrigation water over the entire year in double-cropping rice paddies; increased the rice yield by 1004.16 kg/ha; increased the effective utilization and efficient use of rainfall and irrigation water by 21.1% and 18.8%, respectively; and reduced the surface runoff discharges of ammonia nitrogen, nitrate nitrogen, total phosphorus (TP), and total nitrogen (TN) by 18.6%, 11.1%, 15.4%, and 16.0%, respectively
This study showed that the respective removal rates for TN and TP can reach above 8.6% and 22.9% through dredging of sediments, selection of appropriate wetland plants, and control of hydraulic retention time and paddy to wetland area ratio

Summary

Introduction

River in the northern region of Jiangxi Province, is the largest freshwater lake in China, regulating a yearly average of 145 billion m3 of water and constituting approximately 15.6% of the runoff channeled into the Yangtze River [1,2]. The Poyang Lake drainage basin is located within the subtropical monsoon climate zone, covering 1.9 million km of arable land with an effective irrigation area of 1.6 million km and total grain output of 17.9 million tons. It is one of the most important agricultural, economic, and grain-producing zones in China [4]

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