引用本文:郑海金,左继超,奚同行,聂小飞,王凌云,刘 昭.红壤坡地氮的径流输出通量及形态组成[J].土壤学报,2018,55(5):1168-1178.
ZHENG Haijin,ZUO Jichao,XI Tonghang,NIE Xiaofei,WANG Lingyun,LIU Zhao.Nitrogen Output through Runoff on Red Soil Slope and Its Composition[J].Acta Pedologica Sinica,2018,55(5):1168-1178
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红壤坡地氮的径流输出通量及形态组成
郑海金,左继超,奚同行,聂小飞,刘 昭,王凌云
江西省水土保持科学研究院,江西省土壤侵蚀与防治重点实验室,江西省水土保持科学研究院,江西省土壤侵蚀与防治重点实验室,江西省水土保持科学研究院,江西省土壤侵蚀与防治重点实验室,江西省水土保持科学研究院,江西省土壤侵蚀与防治重点实验室,江西省水土保持科学研究院,江西省土壤侵蚀与防治重点实验室,江西省水土保持科学研究院,江西省土壤侵蚀与防治重点实验室
摘要:
为研究自然降雨条件下红壤坡地氮素输出特征,于2015年5月—2016年5月采用野外大型土壤水分渗漏试验装置,对赣北第四纪红壤坡地植草覆盖、干草覆盖和裸露对照3种处理的地表径流和壤中流中不同形态氮素的输出开展了试验观测。结果表明:(1)在侵蚀不明显的第四纪红壤坡地,TN (总氮)、DIN(溶解态无机氮)、DON(溶解态有机氮)和PN(泥沙颗粒态氮)主要随105 cm壤中流输出,占径流输出总通量的71%,而随地表径流和30 cm、60 cm壤中流输出通量分别为23%和6%;(2)氮素随壤中流输出主要以溶解态(DTN(溶解态总氮)占TN比例为54.8%~86.9%)为主,DTN又以无机态(DIN占DTN比例为57.8%~97.1%)尤其是NO3--N(硝态氮)为主。氮素随地表径流输出的主要形态则随处理措施的不同而不同;(3)保留草被覆盖可以较好地削减氮素径流流失,而采取干草覆盖有增大氮素径流流失尤其是深层损失的风险。
关键词:  红壤  植草覆盖  干草覆盖  氮损失  径流  壤中流
DOI:10.11766/trxb201712200550
分类号:
基金项目:国家自然科学基金项目(41401311)、 江西省自然科学基金项目(20171ACB21072)和江西省杰出人才资助计划(20171BCB23080)资助
Nitrogen Output through Runoff on Red Soil Slope and Its Composition
ZHENG Haijin,ZUO Jichao,XI Tonghang,NIE Xiaofei,LIU Zhao and WANG Lingyun
Jiangxi Institute of Soil and Water Conservation, Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention,Jiangxi Institute of Soil and Water Conservation, Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention,Jiangxi Institute of Soil and Water Conservation, Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention,Jiangxi Institute of Soil and Water Conservation, Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention,Jiangxi Institute of Soil and Water Conservation, Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention,Jiangxi Institute of Soil and Water Conservation, Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention
Abstract:
【Objective】The development of agriculture in the sloping uplands of red soil has been restricted by low water use efficiency, high temperatures and low fertilizer use efficiency.Interflow in the soil has been playing a important role in runoff generation, nutrient loss and soil erosion. Carrying soil nutrients along, it merges into rainfall-induced runoff, which flows into water bodies, thus causing environmental problems, like waterbody eutrophication.Nitrogen (N) as one of the common soil nutrients causing eutrophication is highly mobile in the soil because it is hardly absorbed and fixed by soil particles, so it moves easily with surface runoff and interflow as its main pathway of migration.Consequently, to study soil nitrogen loss related to the joint effect of surface runoff and interflow on slope lands is of great significance. In some regions, plentiful and concentrated rainfall results in surface runoff and interflow that enhances nutrient migration.Recently, researchers have studied patterns of nitrogen migration in red soil through surface flow and its impacting factors, as well as generation of interflows and its influence on nitrogen output.However, so far little has been reported on investigations that have taken into full account the joint effect of surface flow and interflow on nitrogen migration in red soil.【Method】In order to explore characteristics of nitrogen output in sloping uplands of red soil under natural rainfall, large-scale lysimeters were used in a field experiment carried out during the year from May 2015 to May 2016, on a sloping upland of quaternary red soil in Jiangxi, China. The experiment had three treatments, i.e. planted with grass, mulched with straw, and bare land laid out for observation of forms of nitrogen lost with surface flow and interflow (30, 60 and 105 cm) relative to treatment under natural rainfall.【Result】 Results show: (1) Interflow at 105 cm depth was an important channel of N loss on the slope of red soil where erosion wasn’t serious. The interflow in the soil layer 105 cm in depth contributed more than 71% of the total N loss while surface runoff and interflows in the soil layers 30 and 60 cm in depth did less than 23% and 6%, respectively; (2) N in the interflow was mainly in the form of dissolved N, composed principally of dissolved inorganic nitrogen (DIN), especially nitrate nitrogen. The proportion of DTN (dissolved total nitrogen) in TN was 54.8%~86.9% and that of DIN in DTN was 57.8%~97.1% in the interflow. The proportions of various forms of N in the surface runoff varied with the treatment; and (3) Grass coverage effectively reduced N runoff loss, while straw mulch increased the risk of N leaching loss. 【Conclusion】All these findings in the experiment provide certain scientific support to control of N runoff loss from red soil slopelands by establishing a suitable vegetation cover. The key to reduction of nitrogen loss from agricultural fields is to control the formation of interflow or subsurface runoff in sloping uplands of red soil slope and to reduce content of nitrate nitrogen in interflow.
Key words:  Red soil  Grass cover  Straw mulch  Nitrogen loss  Runoff  Interflow