土壤初始含水率对涌泉根灌土壤水分及氮素运移特性的影响

发布时间：2018-04-16 18:00

本文选题：涌泉根灌 + 土壤初始含水率　；参考：《水土保持学报》2017年04期

【摘要】：为了探究涌泉根灌水肥一体化灌溉在不同土壤初始含水率下水氮运移特性,通过室内肥液入渗试验,研究了不同土壤初始含水率(4.13%,7.21%,8.77%,11.06%,14.01%)条件下入渗特性、湿润锋运移、土壤水分以及铵态氮和硝态氮的运移特性,建立了涌泉根灌累积入渗量、各向湿润锋运移距离与不同土壤初始含水率之间的关系,提出了不同初始含水率下涌泉根灌累积入渗量、各向湿润锋运移距离的经验模型。结果表明:累积入渗量、各向湿润锋运移距离以及湿润体内水分和氮素的分布、转化等均不同程度地受到土壤初始含水率的影响。同一时刻条件下,累积入渗量随着土壤初始含水率的增大而减小,而湿润锋运移距离却呈现出增大的趋势;土壤初始含水率越大,湿润体体积越大,湿润体内水分、铵态氮和硝态氮的分布范围越广泛;距离灌水器出水孔越近,土壤中的铵态氮和硝态氮含量越高。入渗系数K随着土壤初始含水率的增大而减小,入渗指数α随着土壤初始含水率的增大而增大;水平湿润锋拟合参数a、b均随土壤初始含水率的增大而增大,竖直向下湿润锋运移指数c随着土壤初始含水率的增大而增大,入渗指数d随着土壤初始含水率的增大而减小。随着土壤水分再分布的持续进行,湿润体内水分分布越加均匀,采用克里斯琴森均匀系数Cu评价灌水结束、再分布1,3天条件下湿润体内水分分布均匀度依次为61.99%,74.27%和83.60%;湿润体内铵态氮含量逐渐减小,但铵态氮的分布区域基本无变化;湿润体内硝态氮分布区域变大,平均值呈增大,最值区域有下移趋势。研究成果为进一步研究涌泉根灌水氮高效利用技术奠定了基础。
[Abstract]:In order to investigate the characteristics of nitrogen and water transport in different initial soil moisture content in Yongquan root irrigation and fertilizer integration irrigation, the infiltration characteristics and wet front migration of different initial soil moisture content were studied under the condition of different initial soil moisture content 4.13 ~ 7.21% ~ 8.77 ~ 11.06% ~ 14.01%).Based on the characteristics of soil moisture, ammonium and nitrate transport, the relationship between the cumulative infiltration of Yongquan root irrigation, the distance of moisture front migration and the initial moisture content of different soils was established.An empirical model for the cumulative infiltration of root irrigation and the migration distance of each wetting front under different initial water content was proposed.The results showed that the cumulative infiltration amount, the migration distance to the wetting front, the distribution of water and nitrogen in the wetting body, and the transformation were all affected by the initial moisture content of the soil in varying degrees.At the same time, the cumulative infiltration decreased with the increase of initial soil moisture content, but the distance of moisture front migration showed an increasing trend, the larger the initial moisture content of soil, the larger the volume of wetted body and the moisture in the moist body.The distribution range of ammonium nitrogen and nitrate nitrogen is wider, and the more close to the outlet of irrigated water, the higher the content of ammonium nitrogen and nitrate nitrogen in soil.The infiltration coefficient K decreases with the increase of the initial soil moisture content, the infiltration index 伪 increases with the increase of the initial soil moisture content, and the horizontal wetting front fitting parameter ab increases with the increase of the initial soil moisture content.The vertical downward moisture front migration index c increased with the increase of initial soil moisture content, and the infiltration index d decreased with the increase of soil initial moisture content.With the continuous redistribution of soil water, the moisture distribution in the moist body became more and more uniform, and the Christiansen uniform coefficient Cu was used to evaluate the end of irrigation.The distribution uniformity of water in moist body was 61.9974.27% and 83.600.The content of ammonium nitrogen in moist body gradually decreased, but the distribution area of ammonium nitrogen remained unchanged, the distribution area of nitrate nitrogen in moist body became larger and the average value increased.The maximum region has a downward trend.The results laid a foundation for further study on the technology of irrigation and nitrogen efficient utilization in Yongquan root.
【作者单位】：西安理工大学水利水电学院;
【基金】：国家重点研发计划课题项目(2016YFC0400204) 国家自然科学基金项目(51279157,51479161) 国家农业公益项目(201203003)
【分类号】：S152.7;S153

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