滁州花山水文实验流域氮收支研究

摘要

基于调查数据和监测实验数据，对滁州花山水文实验流域氮收入与支出进行了研究。对花山流域内人口、作物种植面积、施肥量、产量、畜禽养殖等进行调查，对大气氮湿沉降、径流含氮量、作物籽粒及秸秆含氮量等进行监测和分析，计算2012年10月—2013年9月及2013年10月—2014年9月这2个灌溉年流域氮收支，分析降雨与径流对流域氮收支的影响。2个灌溉年大气氮沉降通量分别为26�10和26�32 kg·hm－2·a－1，氮径流流失模数分别为3�86和8�95 kg·hm－2·a－1，占氮总输出量的比例分别为6�54％和13�98％；2个灌溉年的化肥氮均为流域最主要的氮输入项，分别占氮总输入的50�46％和50�36％；作物收获是流域氮最主要的输出项，分别占氮总输出的56�68％和52�17％；氮盈余量分别为59�94和55�06 kg·hm－2·a－1。氮随径流流失量与径流量有关，花山流域存在潜在富营养化趋势。%Based on the data collected through surveys, monitoring and experiments, a study was carried out on nitrogen budgeting of the Huashan hydrological experiment watershed in Chuzhou. A survey on population, crop planting area, ferti⁃lization, crop yield, livestock and poultry breeding was conducted and wet deposition of atmospheric nitrogen and nitrogen content in runoff and in grain and straw were measured and analyzed. Nitrogen budgeting of the watershed in the two irriga⁃tion years from October, 2012 to September, 2013 and from October, 2013 to September, 2014 were worked out, and im⁃pacts of rainfall and runoff on N budgeting of the watershed were analyzed. Although wet deposition of atmospheric nitrogen was affected by precipitation, in the two irrigation years,the flux of atmospheric nitrogen deposition was 26�10 and 26�32 kg·hm-2 ·a-1 , separately, posing a difference of less than 1%, and the modulus of nitrogen loss with runoff was 3�86 and 8�95 kg·hm-2 ·a-1 , separately, accounting for 6�54% and 13�98% of the total nitrogen output of their respective years, with the latter being over twice as high as the former;chemical fertilizer nitrogen was the main nitrogen input of the watershed, contributing 50�46% and 50�36% to the total nitrogen inputs;nitrogen removal with crop harvest was the main nitrogen output of the watershed, accounting for 56�68% and 52�17% of the total nitrogen output;nitrogen surplus was 59�94 and 55�06 kg·hm-2 ·a-1 , separately for the two years. Therefore, it could be concluded that nitrogen loss is relat⁃ed to runoff and that a potential trend towards eutrophication exists in the Huashan hydrological experimental watershed.