混合植物型生态浮岛对乡村河道水体的净化效果

研究旨在筛选对邯郸市乡村河道水体净化效果较好的生态浮岛植物组合模式,主要研究静态条件下,多种植物进行不同组合搭配的生态浮岛对乡村河道水体的净化效果,选取水葫芦、再力花、美人蕉、慈姑、水芹作为供试植物,比较5种组合对水体中COD、TP、NH4+-N等污染物的去除效率。经过38d试验,结果表明：水芹+慈姑+美人蕉+水葫芦、美人蕉+再力花+水葫芦对COD去除率较高,分别为35.5%、31.2%；水芹+慈姑+美人蕉+水葫芦、美人蕉+再力花+水葫芦对TP去除率较高,分别为81.6%、77.3%；水芹+慈姑+美人蕉+水葫芦、水葫芦+再力花+美人蕉+水芹对NH4+-N去除率较高,分别为55.4%、53.9%；混合植物型生态浮岛对乡村河道水体的净化有显著效果。

Variation Characteristics and Influence of Precipitation Resources During Crop Growing Season in Lower Reaches of the Yangtze River: A Case Study of Shanghai

This paper aims to make appropriate use of the agricultural climatic resources in rice crop growing season, as well as to improve the ability of disaster prevention and mitigation in agriculture. The characteristics of spatial and temporal distributions and variations of precipitation resources during single-crop late rice growing season are analyzed by using the index of precipitation-concentration degree(PCD) and precipitation-concentration period (PCP), based on the daily climatic data of 10 weather stations in Shanghai during 1961 to 2015. The results show that in the recent 55 years the precipitation has an increase tendency, and the linear trend rate of precipitation is 33.6/10a;The intensity of precipitation of heavy rain and rainstorm increased（p＜0.05）,the average growth rate of them were 33.6 and 32.0mm per10 years respectively. Precipitation days have little change indistinctively, and the precipitation days have obvious inverse relationship with different precipitation magnitude, and over the significant level at 0.01. The coefficient of variation of precipitation is smaller in the 1995-1997, 2008-2011 and 2011-2013 years, and the relative change rate of average precipitation in three years shows a rising trend(p＜0.01). The variation trend of the precipitation-concentration degree (PCD) is not significant, and uneven distribution of precipitation, the precipitations concentration period (PCP) is mainly focused on June 19 - August 7, and the mean is on July 14. These results can provided a scientific reference for the utilization of the precipitation resources of crop growing season of single-crop late rice and the response to climate change.