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| Effects of aquatic plants on phosphorus adsorption characteristics by sediments in ecological ditches |
| Received:August 18, 2015 |
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| KeyWord:ecological ditch;aquatic plant;sediment phosphorus adsorption;Langmuir equation |
| Author Name | Affiliation | E-mail | | LI Hong-fang | Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China | | | LIU Feng | Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China | liufeng@isa.ac.cn | | XIAO Run-lin | Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China | | | HE Yang | Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China | | | WANG Di | Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China | | | WU Jin-shui | Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China | |
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| Abstract: |
| Ecological ditches play important roles in controlling agricultural pollution of nitrogen and phosphorus. Here three ecological ditches were selected to investigate properties and P adsorption capacities of sediments. The sediment samples were collected at the inlet(S1), mid-section(S2), and outlet(S3) of a ditch. Total P concentrations in the sediments ranged from 0.19 to 0.60 g·kg-1. Total P increased, but pH values decreased along water flow direction. Oxalate extractable P(Pox) and organic matters(OM) were significantly and positively related with total P(P < 0.01, R2=0.920 and P<0.05, R2=0.549, respectively; n=9). The Langmuir equation showed good fitting of P adsorption. The equilibrium P concentration(EPC0), sorption maximum(Smax), and adsorption constant(Kc) were 0.08~0.38 mg·L-1, 555.6~909.1 mg·kg-1, and 0.18~0.52 L·mg-1, respectively. The sediments from S2, located at the joint site of two aquatic plants Pontederia cordata and Myriophyllum aquaticum, had the highest Smax and lowest EPC0, followed by S3. The S1 sediments had the lowest Smax and highest EPC0. Therefore, planting and rational combination of aquatic plants influence sediment properties, improve P adsorption capacity, and reduce the potential risk of P losses from the ditches. |
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