青土湖间断性水淹干扰对白刺沙丘土壤特性的影响

Effect of Intermittent Flooding Disturbance of Qingtu Lake on Soil Characteristics of Nitraria spinosa Sand Dune

以青土湖过渡带3个不同立地类型(常淹水中的白刺沙丘、固定白刺沙丘、半固定白刺沙丘)的白刺灌丛沙丘为研究对象,采用空间代替时间的方法,测定间断性水淹前后白刺群落土壤水分、土壤理化性质等参数。结果表明,常淹水中的沙丘的土壤全氮含量总体在沙丘中部最大,沙丘上部次之,沙丘下部最小;固定沙丘的土壤全氮含量在沙丘上部较大,沙丘中部各土层的全氮含量均大于沙丘下部;半固定沙丘的土壤全氮含量在表土层达到最大值。常淹水中的沙丘的土壤全钾含量在沙丘上部表土层较低,沙丘中部表土层较高,沙丘下部在土层较深处全钾含量较高;固定沙丘的土壤全钾含量沙丘上部随着土层深度的增加,全钾含量变化不明显,沙丘中部在表土层最大;半固定沙丘的土壤全钾含量5~10cm达到最大值,20~40cm达到最小值。常淹水中的沙丘不同部位的土壤含水量均处于缓慢上升趋势;固定沙丘的土壤含水量在沙丘上部处于上升,沙丘中部先上升后下降,沙丘下部先下降后上升;半固定沙丘土壤含水量呈先上升后下降趋势。常淹水中的沙丘的土壤有机碳含量随着土壤深度的增加均呈不同程度降低趋势;在固定沙丘上,沙丘下部有机碳含量先上升后下降,沙丘中部有机碳含量先下降后上升,沙丘上部有机碳含量呈下降—上升—下降的趋势。在半固定沙丘上,有机碳含量随着土壤深度的增加而增加。

Three different site types of Nitraria spinosa shrub sandbags in the transition zone of Qingtu Lake(normally flooded,fixed and semi-fixed)were taken as the research objects,and the parameters of soil moisture and soil physical and chemical properties of Nitraria spinosa community before and after intermittent flooding were measured by using the method of space instead of time.The results showed that the total nitrogen content of the soil normally flooded was the largest in the middle of the sand dune,the second in the upper part of the sand dune,and the smallest in the lower part of the sand dune;the total nitrogen content of the soil in the fixed dune was larger in the upper part of the dune,and the total nitrogen content of each soil layer in the middle part of the dune was greater than that in the lower part of the dune;the soil total nitrogen content of semi-fixed dunes reached the maximum in the topsoil layer.The total potassium content of the topsoil layer normally flooded was lower in the upper topsoil layer of the sand dune,higher in the middle topsoil layer of the sand dune,and higher in the lower part of the sand dune;the total potassium content of fixed dunes in the upper part of the dune did not change significantly with the increase of soil depth,and the total potassium content in the middle part of the dune was the largest in the topsoil;the total potassium content of semi-fixed dune soil reached the maximum value at 5-10 cm and the minimum value at 20-40 cm.The soil water content in different parts of sand dunes in normal flooding was in a slow upward trend.The soil water content of fixed dunes was rising in the upper part of the dune,first rising and then falling in the middle part of the dune,and first falling and then rising in the lower part of the dune.The soil water content of semi-fixed dunes showed a trend of first increasing and then decreasing.The content of soil organic carbon in sand dunes in normal flooding decreased to varying degrees with the increase of soil depth.On fixed dunes,the organic carbon content in the lower part of the dune first rise and then decreased,the organic carbon content in the middle part of the dune first decreased and then rise,the organic carbon content in the upper part of the dune presented a downward-upward-downward trend.