摘要
以北京东郊永乐店一块农田为背景,将田间取样点所在的土壤剖面假设为一系列不发生相互作用的一维土柱,根据实测的土壤有机质含量,假定不同取样点的土壤有机氮的矿化速率常数(零级动力学)与有机质含量成正比,运用HYDRUS1D软件,分别就考虑和不考虑有机氮矿化速率的空间变异性两种方案,对2001年夏玉米生育期农田尺度下土壤水分运动和硝态氮淋失动态进行了数值分析。模拟结果表明:有机氮矿化速率的空间变异性对剖面250cm埋深处累积硝态氮淋失量的影响很小,其差异主要在于前者影响了土壤氮素的转化量;剖面250cm埋深处平均的土壤水渗透量和累积硝态氮淋失量分别为1.35mm、0.0065mg/cm2,变异系数大于1.8,表现出很强的空间变异性。模拟结果的地统计学分析表明:蒸发量和蒸腾量,收获时剖面250、150cm埋深处的土壤水通量的半方差函数均可用球状模型描述,其变程相近,约为8.7m;土壤水渗透量与累积硝态氮淋失量表现为相互独立的空间结构。考虑有机氮矿化速率空间变异性的土壤氮素净转化量可用球状模型描述,其变程与有机质含量的变程接近,约为4.7m。
This study was conducted to investigate spatial variability of water percolation and nitrate leaching in a 27m × 27m plot, located in Tongzhou District, Beijing, during the growing season of summer maize in 2001. It was assumed that the field was composed of a number of non-interacting 1-D soil columns. According to the measured data it was assumed that the zero-order mineralization rate constant was appropriate to soil organic matter constant and its spatial distribution was obtained. By software HYDRUS-1D soil water percolation and nitrate leaching at the depth of 250cm for two scenarios （with and without considering of spatial variability of mineralization） were simulated. The results showed that ： 1. there was little difference of nitrate leaching between two scenarios and nitrogen transformation was significantly affected by spatial variability of mineralization; 2. the average soil water percolation and nitrate leaching at field scale were 1.35mm and 0.0065mg/cm^2 respectively （CV 〉 1.8）. Results of geostatistics showed that semi-variance of evaporation, transpiration, water flux at the depth of 250cm and 150cm can be fitted by spherical model, senti-variance of water percolation and nitrate leaching was described by pure nugget model. Net N transformation with considering spatial variability of mineralization was fitted by spherical model and its range was approximate to that of organic matter.
出处
《水利学报》
EI
CSCD
北大核心
2005年第9期1067-1076,共10页
Journal of Hydraulic Engineering
基金
国家自然科学基金项目(50479012)
关键词
农田尺度
空间变异性
硝态氮
矿化作用
数值模拟
地统计学
夏玉米
field scale
spatial variability
nitrate nitrogen
mineralization
numerical simulation
geostatistics
summer maize
作者简介
马军花（1975-），女，河北兴隆人．博士生，主要从事土壤氮素运移的数学模拟研究。
