单次和间歇性降雨下紫色土坡地壤中硝氮迁移特征  

Characteristics of Nitrate Nitrogen Transport of Purple Sloped Soils in Response to Single and Intermittent Rainfalls

作　　者：谢梅香 洪大林[1] 付静 张展羽[2] 郑成鑫 张平仓[3] XIE Meixiang;HONG Dalin;FU Jing;ZHANG Zhanyu;ZHENG Chengxin;ZHANG Pingcang(Department of Rural Water Management,Nanjing Hydraulic Research Institute,Nanjing 210029;College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098;Soil and Water Conservation Department,Yangtze River Scientific Research Institute,Wuhan 430010)

机构地区：[1]南京水利科学研究院农村水利研究所,南京210029 [2]河海大学水利水电学院,南京210098 [3]长江科学院水土保持研究所,武汉430010

出　　处：《水土保持学报》2022年第1期24-29,共6页Journal of Soil and Water Conservation

基　　金：中央级公益性科研院所基本科研业务费专项(Y921007)。

摘　　要：为探究不同降雨条件下不同观测时期硝氮在紫色土坡地中的迁移特征,通过室内土槽和人工模拟降雨装置,设置单次降雨和间歇性多次(12次)降雨条件,分别探讨短时期和长时期下的紫色土壤中硝氮迁移特征。结果表明:在单次降雨后短期内紫色土坡地距地表15 cm处土壤水和硝氮均匀地向下距地表35 cm土壤坡脚处迁移,而在间歇性12次降雨条件下,前6次降雨中观测点硝氮浓度由初始345.7 mg/L急速下降至99.7 mg/L;第7次到第9次降雨过程中硝氮浓度由平均值69.7 mg/L缓慢减少至52.0 mg/L,在最后的降雨中趋于稳定不变。随着降雨发生,硝氮在土壤中主要向下迁移,且坡顶处硝氮的迁移幅度最小,壤中流携带流失的硝氮浓度值约为土壤中硝氮浓度值的1/3。整体上壤中硝氮流失呈现出初期3次降雨后快速下降的趋势。研究结果从间歇性降雨的全新视角为紫色土坡地硝氮迁移流失特征研究提供依据和参考。To investigate characteristics of nitrate nitrogen transport in purple sloped soils at different periods under different rainfall events,laboratory soil tanks and simulated rainfall installation were equipped to set each single and total 12 intermittent rainfalls,and nitrate transport characteristics during short and long time periods were discussed respectively.In each soil tank,eight observed points were designed uniformly along the soil profile.The results showed that the soil water and nitrate nitrogen of purple sloped soils transported evenly from the upper 15 cm depth soil layer to the foot slope of lower 35 cm depth soil layer.However,nitrate concentrations of observed points declined rapidly from initial 345.7 mg/L to 99.7 mg/L during the first 6 rainfall events of 12 intermittent rainfalls;mean nitrate concentrations decreased from 69.7 mg/L to 52.0 mg/L during the 7^(th) to 9^(th) rainfall event,and tended to stable.As rainfall occurred,nitrate nitrogen transported towards the lower and foot of sloped soils,and the top of slope showed minimal transport.In addition,the nitrate concentration of subsurface outflow was about 1/3 of that of subsurface soil water.Overall,subsurface nitrate loss showed rapid decrease after 3 rainfall events.This research provided better understanding for nitrate transport and loss mechanism of purple sloped farmland as response to intermittent rainfall events,which was from a bran-new perspective.

关 键 词：单次降雨 间歇性降雨 土壤水运移 壤中流 硝氮迁移 硝氮流失量 

分 类 号：S157.1[农业科学—土壤学]