摘要
大气湿沉降作为农田生态系统养分的重要来源却一直没有得到足够的重视。文章通过常规农作条件,采用自动降雨收集器结合田间实验方法,重点研究了红壤旱地牧草马唐(Digitaria ischaemum)和蔬菜冬萝卜(Raphanus sativus)连作期间大气湿沉降氮素特征,估算了湿沉降向该生态系统输入的氮量,讨论了其对该生态系统氮素平衡的贡献。结果发现,该研究区域不同月份大气湿沉降T-N平均质量浓度为3.91mg·L-1,其中NH4+-N、NO3--N的分别为1.21、0.61mg·L-1;试验期间,湿沉降输入马唐-冬萝卜连作系统的T-N为34.34kg·hm-2,其中冬萝卜生长期最多,占67.88%,湿沉降T-N对该系统氮素输入、输出、盈余的贡献分别为12.97%、17.65%、48.90%。湿沉降T-N对马唐生态系统氮素输入、输出、盈余的贡献分别为6.45%、16.54%、10.57%;对冬萝卜生态系统氮素输入、输出的贡献分别为24.86%和18.23%。红壤旱地普遍具有"酸瘦黏板"的特点,氮素作为一种重要的生命物质和作物营养的必需元素,对作物产量和人民生活质量的提高具有重要的意义。研究结果表明,湿沉降对农田生态系统的影响不容忽视。
Atmospheric wet deposition plays an important role in origin of nutrition,nor can its function be neglected in farmland ecosystem.The characteristic of wet deposition was studied,the nitrogen input by wet deposition was reckoned and the contribution of the nitrogen input to nitrogen balance was discussed in the graze（Digitaria ischaemum）and the vegetable（Raphanus sativus） rotation ecosystem by automatic precipitation collector combined with the method of field experiment. The results were showed that the concentration of T-N（total nitrogen）in wet deposition was averagely 3.91 mg·L^-1,which the concentrations of NH4 ^＋ -N and NO3 ^- -N were respectively 1.21 mg·L^-1 and 0.61 mg·L^-1.During the whole trial,the T-N input from wet deposition was 34.34 kg·hm^-2 in graze-vegetable economy,which from vegetable ecosystem was more and accounted for 67.88%. Besides,its contributions to the input,output and surplus of T-N were apart 12.97%,17.65%and 48.90%in the graze-vegetable rotation ecosystem.Furthermore,the T-N from wet deposition contributed to the input,output and surplus of T-N by 6.45%,16.54%and 10.57%in the graze ecosystem.And it contributed to input and output surplus of T-N by 24.86%and 18.23%in the vegetable ecosystem. Red soil usually has the characteristics of acid,thin,sticky and hard in China.And nitrogen works as an important living material and is one of necessary elements for crops,which is important to crop yield and quality of community life.So the ecological function of atmospheric wet deposition can not be neglected.
出处
《生态环境》
CSCD
北大核心
2007年第6期1714-1718,共5页
Ecology and Environmnet
基金
国家自然科学基金项目(40305019)
中国科学院知识创新工程项目(KZCX2-413)
关键词
红壤旱地
湿沉降
生态系统
upland red soil
wet deposition
ecosystem
