Analysis on the Content of Nitrogen and Phosphorus in Root Exfoliation of Water Hyacinth (Eichhornia crassipes)

• Main Authors: ZHANG Ying-ying, WEN Xue-zheng, LIU Hai-qin, LI Xiao-ming, YAN Shao-hua, QIN Hong-jie, ZHANG Zhi-yong
• Format: Article
• Language: zho
• Published: Agro-Environmental Protection Institute, Ministry of Agriculture 2015-10-01
• Series: Journal of Agricultural Resources and Environment
• Subjects: water hyacinth; root exfoliation; nitrogen; phosphorus; eutrophic water
• Online Access: http://www.aed.org.cn/nyzyyhjxb/html/2015/5/20150510.htm
• ISSN: 2095-6819; 2095-6819

In order to discuss the effect of the release of nitrogen and phosphorus from root exfoliation of water hyacinth (Eichhornia crassipes) on water quality during the course of eutrophic water purification, water hyacinth was cultivated in confined fence facilities in the Caohai of Dianchi Lake. The plant and root exfoliation were collected every 30 days from May to November in the year of 2013, and fresh and dry weight as well as nitrogen and phosphorus contents were determined. The results showed there was no significant difference (P>0.05) between May-Sep (rapid growth period) and Oct-Nov (gradual withering period) on the contents of nitrogen and phosphorus in dry matter of water hyacinth, while the growth rate of water hyacinth in rapid growth period was significantly (P<0.05) higher than that in gradual withering period. As a result, the purification of nitrogen and phosphorus in water by water hyacinth was more evident in rapid growth period than that in gradual withering period. The fresh weight, dry weight, nitrogen content, and phosphorus content of root exfoliation only accounted for 7.72%, 2.10%, 2.50%, and 3.05% of the increment of fresh weight, dry weight, nitrogen content, and phosphorus content of water hyacinth, respectively. The results implied that compared with the amount of nitrogen and phosphorus taken out of the lake water by water hyacinth, the amount returned into the lake water through root exfoliation was much lower. Confined growth of water hyacinth in the lake exerted no negative effect on the lake water quality.