摘要
本文研究了甜菜生育期间种植地、休闲地黑土无机氮的变化动态。结果表明,种植地无机氮的变化受作物生长的影响。可分为3个阶段:氮素供求平衡期、氮素供求尖锐期和氮素供求缓和期。休闲地无机氮的变化动态可分为4个阶段:积累平缓期、下渗积累期、积累旺盛期和积累终止期。其中5月中旬、8月中旬、9月上旬和10月上旬4个测定日期的无机氮值(0～90cm 土层),年际间差异不显著。用该4个数值可绘出土壤无机氮动态曲线,科学地反映出土壤供氮水平,可作为甜菜定量施氮的重要参数之一。
A field experiment was conducted in 1989～1990 to study the dynamics of inorganic ni-trogen in the black soil layer 0～90cm under crop and fallow during vegetation period ofsugarbeet.The resulsts were as follows:The dynamics of inorganic nitrogen in the black soil undercrop mainly depended on the intensity of nitrogen uptake by sugarbeet plants at differentgrowth stages.It was divided into three stages:nitrogen balance,sharp opposition and sub-siding stages bet ween soil nitrogen supply and crop requirement.In the fallow soil,dynamics of inorganic nitrogen was divided into four stages:slow ac-cumulation,leaching accumulation,exuberant accumulation and closing accumulation stages.The differences of four inorganic nitrogen values determined in the second ten days in Mayand August and in the first ten days of september and October were not significant.It is pos-sibleto draw the dynamics curve of soil inorganic nitrogen with the four values.The curve in-dicates inorganic nitrogen supply capacity of the soil an is one of the important parametersfor quantitative nitrogen fertilization of sugarbeet.
基金
国家自然科学基金
霍英东教育基金会资助.
关键词
甜菜
黑土
无机氮
土壤
供氮水平
sugarbeet
black soil
dynamics of inorganic nitrogen
nitrogen supply capacity of soil
