Relationship between the Movement of Soil Water and Nitrogen in the Volcanic Ash Soil

火山灰土中土壤水运动与氮素的关系

• 批准号: 09660264
• 负责人: TOYOMITSU Yukio
• 金额: $ 1.6万
• 依托单位: Miyazaki University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660264/
• 关键词: Nitrate nitrogen; Soil water; Leaching; Rainfall; Percolation; Hydraulic conductivity; Solute transport

Potassium nitrate was sprayed over experimental field ( subdivision of 65cm × 150cm ) of the bare field condition in 100gN/mィイD12ィエD1 in order to clarify mutual relationship between movement of soil water and nitrogen, and movement and leaching of the nitrogen were studied from October fifth, 1998 to October fifth, 1999. The soil was collected to 210cm in the auger ( the 20mm diameter ) for the 2 〜 4 week every and every 15cm depth. The quantity of ammonia nitrogen and nitrate nitrogen was obtained by the 10%KCl soil extract. Soil water potential was measured from 30cm to 170cm by the tensiometer in hour by every 20cm depth. And, the volumetric water content was measured to the 90cm depth by the TDR method in 1 hour by every 30cm. Amount of rainfall was recorded throughout the experiment. Results are as follows.(1) Though the TDR method can not be applied to this experimental field, it is possible to obtain amount of change of soil water, because amount of increase of soil water and amount of rainfall agree almost.(2) The increase in the soil water is not always shown, and there is a case in which it is the propagation of the pressure only on the increase of pressure potential in the rainfall time.(3) Zero flux plane in experimental field is located in the vicinity of the 110cm depth.(4) Most disappears on the rain water in many cases from soil layer to the 90cm depth in a few days, and all most of the rain water disappear after 20th.(5) The case that amount of rainfall and soil water were less than the case in which there are many amount of rainfall and soil water mainly disappeared more on the transfer of the nitrogen from the soil layer of the 210cm depth. This supposed for the reason that soil water moves macropore mainly when there is much soil water and soil water moves micropore when there is little soil water. It is considered that that is to say, the nitrogen is mainly retained than the macroscopic pore in the micropore.

为阐明土壤水氮运移的相互关系，于1998年10月5日至1999年10月5日，在裸地条件下，以100 gN/m2·d-12·d-1的浓度，在试验田（65 cm × 150 cm）上喷施硝酸钾，研究了氮素的运移和淋溶规律。每隔15 cm深度，在螺旋钻（直径20 mm）中收集土壤至210 cm，持续2 - 4周。采用10%KCl土壤浸提液测定氨氮和硝态氮含量。在30 ~ 170 cm土层内，每隔20 cm深度，用张力仪测定土壤水势，每小时测定一次。并且，通过TDR方法每30 cm在1小时内测量体积含水量至90 cm深度。在整个实验过程中记录降雨量。结果如下。(1)虽然TDR法不能应用于该试验田，但由于土壤水分增加量与降雨量基本一致，因此可以获得土壤水分变化量。(2)土壤水分的增加并不总是表现出来的，有一种情况下，它是传播的压力只有在降雨时间的压力势的增加。(3)实验场的零通量面位于110 cm深度附近。(4)从土壤层到90 cm深度的降水中，多数在几天内消失，20日以后大部分降水消失。(5)降雨量和土壤水分较少的情况比降雨量多、土壤水分主要消失的情况对210 cm土层中氮素的转移影响更大。这是由于土壤水分多时，土壤水分主要在大孔隙中运移，而土壤水分少时，土壤水分主要在小孔隙中运移。可以认为，也就是说，氮主要保留在孔隙中，而不是宏观孔隙中。