科尔沁沙地21种植物水分提升作用的实证检验
Empirical test of hydraulic lift in 21 plant species in the Horqin sandy land,Inner Mongolia
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摘要: 对科尔沁沙地21种植物开展了水分提升作用检测和发生特点研究。试验采用上下层土壤隔离的自制栽植箱,通过控制上、下层土壤水分含量的方法检测植物水分提升作用。结果表明:有19个参试物种观测到水分提升作用,水分提升作用可能是沙生植物适应干旱环境的普遍特性;植物水分提升作用在00:00—06:00时段内发生频率和提升数量较高;不同物种间水分提升能力存在差异,本研究首次采用每克根系生物量(干质量)24 h可产生的水分提升数量作为比较植物水分提升能力的单位,其数值变化范围为4.86~325.62 g/g之间,平均为72.9 g/g。综合比较认为,乌丹蒿、万年蒿、牧马豆和雾冰藜具有较强的水分提升能力。浅层土壤干旱程度与累计水分提升数量在统计学分析上并未表现出明显的相关性。利用植物水分提升能力改善固沙植被区浅层土壤水分环境条件,对提高半干旱区人工固沙植被的稳定性具有重要意义。Abstract: We examined the hydraulic lift function of 21 psammophytes and clarified the characteristics of this process in the Horqin sandy land,Inner Mongolia. We used self-made growth boxes,in which the soil was separated into upper and lower layers by Vaseline. The water supply to the upper soil was controlled during the examination period. We determined the hydraulic lift effects by measuring the variation of soil water content in the upper soil. Results showed that the hydraulic lift process occured mostly during 00:00 to 06:00 hours. The amounts of hydraulically lifted water were different among species. The increment of soil water content lifted per gram of roots during 24 hours varied between 4.86 and 325.62 g/g, the average is 72.90 g/g. Four species,Artemisia wudanica,A. gmelinii,Thermopsis lanceolata and Bassia dasyphylla had higher hydraulic lift capability among all examined species. No marked correlation was observed between the drought degree of the upper soil and accumulative total water lifted by hydraulic process. It is significant to make use of hydraulic lift capability of psammophytes to improve the water content of shallow soil for artifical vegetations on semiarid sandy lands.