UPTAKE OF NITROGEN FROM SOILS IN RELATION TO SOLUTE DIFFUSION
UPTAKE OF NITROGEN FROM SOILS IN RELATION TO SOLUTE DIFFUSION
复制标题
DOI：
10.1071/sr9680075
复制
发表时间：
1968-01-01
影响因子：
--
通讯作者：
BARLEY, KP
中科院分区：
文献类型：
--
作者：
CLARKE, AL;BARLEY, KP
用一定浓度的溶液润湿砂土或壤土时，硝态氮（KNO3）和铵态氮（KNH3）的表观扩散系数随溶液体积的增加而增加。KNO3的值（0.5-5 x 10-3 cm2/sec）与先前报道的KCl相似，比KNH4的值（0.4-3 x 10-7 cm2/sec）高一个数量级。用两种方法测定了小麦根系消耗硝态氮和铵态氮的速率。一种方法是使用根垫，另一种方法是在薄层土壤中种植单根。在这两种方法中，流向根部的水流都被最小化。氮的吸收遵循一个与搅拌溶液截然不同的模式。硝态氮吸收量随土壤溶液浓度的增加呈线性增加，在100-1000 p.p.m.范围内。此外，虽然在搅拌溶液中铵的吸收速度通常比硝的快，但在土壤中加入等量的硝时，硝的吸收速度远远快于铵。所观察到的氮吸收的变化在很大程度上可归因于土壤对溶质扩散的阻力的变化。
When either a sand or a loam was wetted with solutions of given concentration, the apparent diffusivities of nitrate, KNO3, and ammonium, KNH3, increased with the volume of solution added. Values of KNO3 (0.5-5 x 10-3 cm2/sec) were similar to those reported previously for KCl, and were one order of magnitude higher than the values for KNH4 (0.4-3 x 10-7 cm2/sec). The rate at which wheat roots depleted the sand and loam of nitrate or ammonium was measured by two methods. In one method root mats were used, and in the other single roots were grown through a thin layer of soil. In both methods the flow of water to the roots was minimized. The uptake of nitrogen followed a very different pattern from that reported for stirred solutions. Nitrate uptake increased linearly with soil solution concentration over a wide range, 100-1000 p.p.m. of nitrate nitrogen. Also, although ammonium is generally absorbed more rapidly than nitrate from stirred solutions, nitrate was absorbed far more rapidly than ammonium when equivalent amounts were added to the soil. The observed variations in nitrogen uptake could be largely attributed to changes in the resistance that the soil offered to the diffusion of solutes.