模拟降雨条件下不同植被覆盖度/格局的坡地土壤铵态氮流失特征  

Characteristics of Ammonium Nitrogen (NH_4^+-N) Loss from Slope Lands with Different Vegetation Cover/Patterns Under Simulated Rainfall

作　　者：刘泉[1,2] 李占斌[2,3] 李鹏[3] 黄文军[1] 

机构地区：[1]绵阳师范学院,四川绵阳621000 [2]中国科学院水利部水土保持研究所,陕西杨凌712100 [3]西安理工大学,西安710048

出　　处：《水土保持研究》2017年第1期75-78,共4页Research of Soil and Water Conservation

基　　金：国家科技支撑计划课题"农田水土保持工程与耕作关键技术研究"(2011BAD31B01);绵阳师范学院博士科研启动项目"嘉陵江中游典型小流域水沙-养分(N;P)淋失机理研究"(QD2014A002);绵阳师范学院青年资助项目"坡耕地水土流失过程中养分输移机理研究"(2013B09)

摘　　要：尽管采取各种措施控制农业氮素污染,但大量氮素的流失仍然成为农业非点源污染的主要来源之一。采用室内模拟降雨的方式,选用了3种植被覆盖度(25%,50%和75%)、9种不同的植被格局,对21°坡面铵态氮随径流和泥沙流失迁移规律进行了研究。结果表明:径流和泥沙流失的控制关键期在初期产流阶段。植被覆盖度25%时,铵态氮流失规律不明显。植被覆盖度50%时,在中期和后期产流阶段径流和泥沙携带的铵态氮流失量分别占累计流失量71.2%~82.8%,应加强中期和后期产流阶段铵态氮流失量控制。植被覆盖75%时,初期产流阶段是铵态氮流失控制的关键时期。径流与径流结合态铵态氮流失量呈幂函数关系,两者呈显著正相关(p<0.05),泥沙与泥沙结合态铵态氮流失量均呈幂函数关系,并具有极显著正相关性(p<0.01)。径流和泥沙流失是坡面铵态氮流失的两种途径。从削减水沙和养分流失量角度来看,坡下植被格局最强,坡上植被格局次之,坡中植被格局最弱。Although the government has taken various measures to control nitrogen pollution on cropland, large loss of nitrogen along with runoff and sediment is one of primary source of agricultural non-point source pollution. Three types of vegetation coverage （25%, 50% and 75%） including nine vegetation patterns were selected for examining the loss processes of NH^＋-N along with runoff and sediment on the 21° slope land under indoor simulated rainfall condition. The results show that the critical period of controlling runoff and sediment losses is the early runoff stage （ERS）. The pattern of NH＋-N loss is not obvious when vegetation coverage is 25 -, the amounts of NH4^＋-N loss through runoff and sediment in the middle runoff stage and late runoff stage accounted for 71.2% -82. 8% of total losses when vegetation cover is 50%. As for controlling NH4^＋-N loss, the ERS is the best period when vegetation cover is 75%. The relationship between runoff and NH^＋-N loss by runoff （RAN） follows the power function, and runoff is significantly positive correlated with RAN （p〈0.05）. The relationship between sediment and NH4^＋-N loss by sediment （SAN） can be described by power function, and sediment and NH4^＋-N loss are highly significant and positive correlated （p〈0.01）. With respect to three vegetation patterns, the reduction capacity on runoff, sediment and NH^＋-N loss decreases in the order： lower patterns〉upper patterns〉middle patterns.

关 键 词：铵态氮 植被覆盖度/格局 模拟降雨 

分 类 号：S157.1[农业科学—土壤学] S153[农业科学—农业基础科学]