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绿洲农田土壤优先流特征及其对灌溉量的响应

闫加亮1,2,赵文智1**,张勇勇1   

  1. (1中国科学院寒区旱区环境与工程研究所中国生态系统研究网络临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室,  兰州 73000;  2中国科学院大学,  北京 100049)
  • 出版日期:2015-05-18 发布日期:2015-05-18

Characteristics of the preferential flow and its response to irrigation amount in oasis cropland.

YAN Jia-liang1,2, ZHAO Wen-zhi1, ZHANG Yong-yong1   

  1. (1Linze Inland River Basin Research Station, Chinese Ecosystem Research Network/ Key Laboratory of Inland River Ecohydrology, Cold and Arid Regions, Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; 2University of Chinese Academy of Sciences, Beijing 100049, China)
  • Online:2015-05-18 Published:2015-05-18

摘要:

优先流是土壤养分和水分快速通过土壤剖面的普遍物理现象.研究农田土壤优先流特征及其影响因素,对量化绿洲灌溉深层渗漏量、提高水肥利用效率以及降低浅层地下水质污染的风险具有重要意义.在绿洲农田利用亮蓝溶液进行原位染色示踪试验,结果表明:沟与垄位置处的染色路径数目在土壤深度7.3~16.7 cm差异显著,而优先流最大入渗深度差异不显著.优先流最大入渗深度主要受蚂蚁洞穴和灌溉量的影响,平均灌溉量120 mm下优先流的最大入渗深度为(43.1±5.9) cm;受到蚂蚁洞的影响,灌溉量55 mm的样方优先流最大入渗深度达(68.3±7.6) cm.细根(Φ≤2 mm)与优先流显著相关,粗根与优先流相关性不显著,表明植物根系中的细根对优先流的产生有重要作用.绿洲农田土壤优先流特征受到灌溉量、垄沟耕作、蚂蚁洞穴和根系等因素的影响,而蚂蚁洞穴是影响优先流最大入渗深度的不确定因素.
 

Abstract: Preferential flow is a physical process describing how water and solutes move along certain pathways through soil profile. Studying the cropland preferential flow patterns and its influential factors could quantify the deep percolation, improve water and fertilizer use efficiency and reduce the risk of agrochemicals contaminating shallow groundwater in oasis cropland. The dye tracer experiments were carried out in field oasis cropland, using a brilliant blue FCF solution. The results showed that between ridge and furrow, the number of stained paths densities differed significantly at the 7.3-16.7 cm depth of the soil profiles, while the maximum dye depth had no significant difference. The main influence factors of the maximum stained depth were the irrigation amount and the ant burrows. The maximum stained depth was (43.1±5.9) cm with the mean irrigation amount of 120 mm, however, the maximum stained depth was (68.3±7.6) cm with the irrigation amount of 55 mm under the influence of the ant burrows. Root played an important role in preferential flow, but only the fine roots (Φ≤2 mm) were significantly related to the preferential flow in oasis cropland, while the coarse roots were not. In oasis cropland, the characteristics of the preferential flow were influenced by the irrigation amount, the furrow and ridge planting, the ant burrows and the roots, and the ant burrows were an uncertain factor which affected the maximum infiltration depth of the preferential flow.