三河口水库消落带植物水解氮磷释放特征研究

以三河口水库5种消落带优势植物青蒿、艾、醴肠、菵草、酸模叶蓼的地上茎叶部分为样本，库水为实验原水，进行室内水解模拟实验。通过测定上覆水的基本水质指标及氮磷养分浓度，探明消落带植物经过水解后，对水体水环境的影响及不同形态氮磷养分的释放特征和负荷。结果表明：5种植物水淹后均引起上覆水颜色加深且产生异味，pH值下降，浊度增大，电解率增大，溶解氧降低；氮、磷养分得到释放，总氮和总磷的平均释放量分别为4.06和0.78 mg/g,其中颗粒态氮、磷相应占总氮和总磷的43.2%和36.2%;在水库的蓄水初期(30 d),消落带植被向水体释放的氮、磷负荷可达40.4和7.6 kg/hm²,这些将对三河口水库的水环境安全造成影响。

Release characteristics of hydrolyzed nitrogen and phosphorus from dominant plants in Sanhekou Reservoir drawdown zone

The indoor hydrolysis simulation experiment was carried out with the aboveground stems and leaves of five dominant plants in the drawdown zone of Sanhekou reservoir, namely, Artemisia carvifolia Buch-Ham, Artemisia argyi Levl. et Van, Eclipta prostrata L., Bechmannia syzigachne(Steud.) Fem and Polygonum lapathifolium L. as the samples and the reservoir water as the experimental raw water. By measuring the basic water quality indices and the nutrient concentration of nitrogen and phosphorus of the overlying water, we investigated the impact of the plants in the drawdown zone on the water environment and the release characteristics and load of different forms of nitrogen and phosphorus nutrients after hydrolysis. The results showed that when these five plants were inundated, the color of the overlying water deepened, peculiar smell occurred, pH value decreased, turbidity increased, electrolytic rate increased and dissolved oxygen decreased; nitrogen and phosphorus nutrients were released, and the average release amounts of total nitrogen and total phosphorus were 4.06 mg/g and 0.78 mg/g, respectively, among which, the particulate nitrogen and phosphorus accounted for 43.2% and 36.2% of total nitrogen and total phosphorus, respectively; at the initial stage of reservoir impoundment(30 d), the nitrogen and phosphorus load released by vegetation in the drawdown zone to the water body can reach 40.4 kg/hm² and 7.6 kg/hm², which in turn will affect the water environment safety of the Sanhekou Reservoir.