施肥时机对土壤水氮运移转化规律的影响  

Effects of Fertilization Timing on Soil Water and Nitrogen Transport and Transformation

作　　者：马敬东 聂卫波[1] 冯正江 王慧[1] 马孝义[2] MA Jingdong;NIE Weibo;FENG Zhengjiang;WANG Hui;MA Xiaoyi(State Key Laboratory of Ecohydraulics in Northwest Arid Region, Xi’an University of Technology, Xi’an 710048;Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100)

机构地区：[1]西安理工大学省部共建西北旱区生态水利国家重点实验室,西安710048 [2]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《水土保持学报》2022年第4期236-246,共11页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(51579205,51909208);陕西省教育厅重点实验室基金项目(20JS099)。

摘　　要：为揭示不同施肥时机(全过程、前1/2和后1/2入渗水量施肥)下土壤水氮运移转化规律,以砂壤土和黏壤土质地的一维垂直肥液(尿素)入渗试验为基础,重点分析不同施肥时机下土壤水氮分布与再分布过程中的运移转化规律,并量化比较其对土壤中氮素含量的影响。结果表明,施肥时机对土壤累积入渗量和湿润体中水分分布影响微小,但对不同形态氮素运移转化影响显著;砂壤土和黏壤土入渗结束时刻,全过程和后1/2入渗水量施肥时,其尿素态氮、铵态氮(NH_(4)^(+)-N)和硝态氮(NO_(3)^(-)-N)含量均随土层深度增大而减小;前1/2入渗水量施肥时,尿素态氮和NO_(3)^(-)-N含量在湿润体边缘累积,NH_(4)^(+)-N呈先增大后减小趋势,且主要分布在5—25 cm土层;再分布阶段,全过程和后1/2入渗水量施肥时,砂壤土和黏壤土中尿素态氮分别在再分布3天和5天时基本水解完成,同时NH_(4)^(+)-N含量达到峰值,NO_(3)^(-)-N含量再分布10天内未出现下降趋势;前1/2入渗水量施肥时,尿素态氮再分布10天时基本水解完成,NH_(4)^(+)-N含量再分布5~10天达到峰值,NO_(3)^(-)-N含量则呈先增加后减小趋势;后1/2入渗水量和全过程施肥条件下,砂壤土和黏壤土再分布10天时0-40 cm土层中NH_(4)^(+)-N和NO_(3)^(-)-N含量均大于前1/2入渗水量施肥,说明其氮素潜在利用效率高,故推荐畦(沟)灌合理施肥时机为后1/2入渗水量或全过程施肥。研究结果可为农田畦(沟)灌施肥系统的设计和管理提供理论基础和技术支撑。In order to reveal the law of soil water and nitrogen transport and transformation under different fertilization timing(the whole process,the first 1/2 and the last 1/2 infiltration water fertilization),we analyzed the migration and transformation law of soil water and nitrogen distribution and redistribution under different fertilization timing,and compared their effects on soil nitrogen content quantitatively based on the one-dimensional vertical fertilizer solution(urea)infiltration experiment of sandy loam and clay soil.The results showed that fertilization timing had little effect on the cumulative infiltration of soil and the distribution of water in moist body,but it had a significant effect on the transport and transformation of different forms of nitrogen in the process of distribution and redistribution.At the end of infiltration in sandy loam and clay loam,during the whole process and fertilization of the last 1/2 infiltration water,the content of urea nitrogen,ammonium nitrogen(NH^(4)^(+)-N)and nitrate nitrogen(NO_(3)^(-)-N)decreased with the increasing of soil depth.When the first half of the infiltration water was fertilized,the content of urea nitrogen and NO_(3)^(-)-N accumulated at the edge of the wet body,and NH^(4)^(+)-N increased first and then decreased,mainly distributed in 5—25 cm soil layer.In the redistribution stage,urea nitrogen in sandy loam and clay loam was basically hydrolyzed after 3 and 5 days of redistribution during the whole process and the last 1/2 infiltration water fertilization,respectively.At the same time,NH^(4)^(+)-N content reached the peak,and NO_(3)^(-)-N content did not decline within 10 days of redistribution.When the first half of the infiltration water was fertilized,the hydrolysis of urea nitrogen was basically completed after 10 days of redistribution,the content of NH^(4)^(+)-N reached the peak after 5-10 days of redistribution,and the content of NO_(3)^(-)-N increased first and then decreased.Under the condition of the last 1/2 infiltration water and the who

关 键 词：灌溉施肥 施肥时机 土壤水分 水氮运移 

分 类 号：S275.3[农业科学—农业水土工程]