摘要
在室内通过人工配置不同水平土壤容重(1.35、1.40、1.45、1.50 g/cm^3),用土箱进行水肥入渗模拟试验,研究土壤容重对累积入渗量、湿润锋运移、土壤水分以及铵态氮和硝态氮运移的影响,建立以土壤容重和入渗时间为自变量,累积入渗量和各向湿润锋运移距离为因变量的经验模型。结果表明:土壤容重对累积入渗量、各向湿润锋运移距离及湿润体内水分和氮素的分布、转化均具有较为显著的影响。随着土壤容重的减小,累积入渗量、湿润锋运移距离、湿润体内水分、铵态氮及硝态氮含量均呈增大趋势。入渗系数K随着土壤容重的增大而减小,入渗指数α随着土壤容重的增大而增大;在同一时刻,湿润体内铵态氮和硝态氮含量的平均值、变化量及转化率均随着土壤容重的增大而增大。距离灌水器越近,铵态氮、硝态氮含量越高;湿润体内铵态氮分布主要集中在灌水器附近,随着再分布进行,湿润体内铵态氮含量、转化率逐渐减小,转化量逐渐增加。灌水结束、再分布3、5、10、15、20 d条件下,以灌水结束时刻为基准,铵态氮含量降幅依次为2.34%、11.41%、34.22%、59.06%和73.75%。湿润体内硝态氮分布区域与水分分布相似,随着再分布进行,湿润体内硝态氮含量、转化量逐渐增大,再分布15 d达到最大值;而转化率呈现出先增大后减小的趋势,再分布10 d转化率达到最大值。灌水结束、再分布3、5、10、15、20 d条件下,以灌水结束时刻为基准,湿润体内硝态氮含量依次增加0.76%、60.12%、156.95%、204.68%和180.51%。土壤容重对涌泉根灌土壤水分和氮素运移、分布及其转化的影响均较为显著。
The different soil bulk density levels（ 1. 35 g/cm^3,1. 40 g/cm^3,1. 45 g/cm^3 and 1. 50 g/cm^3）were constructed by indoor manual configuration. The experiment of water and fertilizer infiltration was carried out in the soil bin. The effects of soil bulk density on cumulative infiltration,wetting front migration,soil moisture,NH_4~＋-N and NO_4^--N transport were investigated. An empirical model was created,in which the cumulative infiltration amount and the wetting front migration distance were the dependent variables,and the bulk density and infiltration time were independent variables. Results showed that the soil bulk density had a significant effect on the cumulative infiltration,the migration distance of wetting front and the distribution and transformation of moisture and nitrogen in the soil. With the decrease of soil bulk density,the cumulative infiltration,wetting front migration,moisture in the body,NH_4~＋-N and NO_4^--N contents showed an increasing trend. The greater the soil bulk density was,the smaller the infiltration coefficient K became. The greater the soil bulk density was,the greater the infiltration index α became. At the same time,the average value,the change amount and the conversion rates of NH_4~＋-N and NO_4^--N in wetted body were increased with the increase of soil bulk density. The closer the distance to the emitter was,the higher the contents of NH_4~＋-N and NO_4^--N became. The distribution of NH_4~＋-N in the moist body was mostly concentrated in the vicinity of the emitter. With theredistribution,the content of NH_4~＋-N in the wetted soil and the conversion rate were decreased gradually,and the transformation amount was increased gradually. After the redistribution for 3 d,5 d,10 d,15 d and 20 d,with the end of irrigation time as the benchmark,the decline order was 2. 34%,11. 41%,34. 22%,59. 06% and 73. 75%,respectively. The distributions of NO_4^--N in the soil were similar to water. After the redistribution for 3 d,5 d,10 d,15 d and 20 d,with the end of irrigation
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2017年第8期219-228,共10页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家重点研发计划项目(2016YFC0400204)
国家自然科学基金项目(51279157
51479161)
公益性行业(农业)科研专项(201203003)
关键词
涌泉根灌
土壤容重
再分布
模型
氮素运移
bubbled-root irrigation
soil bulk density
redistribution
models
nitrogen migration
