意杨苗木耗水特征与水分利用效率

研究杨树耗水量的变化特征、水分利用效率及其影响因子对杨树生理生态研究、造林树种的选择和林业生态工程建设具有重要的指导价值。以意杨(Populus euramevicana cv.‘I-214’)为研究对象进行盆栽试验,设定了4个处理组,分别为T1处理组(种植意杨,密封处理),T2处理组(种植意杨,非密封处理),T3处理组(不种植意杨,非密封处理),C处理组(不种植意杨,密封处理),定量分析了意杨耗水规律、水分利用效率及土壤蒸发量与植株生理特性、气象环境因子之间的关系。结果表明:(1)4个处理组耗水量变化曲线均呈"单峰型",且在7月份达到最大值,2月份降到最低值。(2)栽植意杨的土壤水分蒸发量占总耗水量的15.9%,全年波动状态稳定,本底流失量占30.4%。(3)在地表覆盖物下的意杨蒸腾耗水量占总耗水量的53.7%,年变化曲线为单峰型;栽培意杨的土壤水分总流失量是不栽培意杨土壤总流失量2.77倍;在裸地上种植意杨的土壤水分总蒸发量仅比没有意杨的裸地土壤多流失7.9%水分。(4)在有地表覆盖物下和裸地上的意杨叶面平均蒸腾强度分别为30.8 g cm~(-2)a~(-1),9.5 g cm~(-2)a~(-1);平均每克生物量耗水量为39.61 g。综上所述,意杨具有很强的蒸腾耗水能力,种植意杨可能会造成造林地区土壤水分大量流失,使该地区深层土壤干燥化,不利于土壤储水调节作用的发挥。

Water consumption characteristics and water use efficiency of poplar

Changes in the water consumption characteristics and water use efficiency of poplar, and the influencing factors were investigated, which is significant to the study of the physiology and ecology of poplars, selection of tree species for forestation, and forest ecological engineering. Four treatment groups were set up for pot culture experiments on poplar. Quantitative analysis showed the relationship between the following characteristics of poplars: water consumption, water use efficiency, soil evaporation, plant physiological properties, meteorological environment factors, and soil moisture. The results showed that: (1) the changing curves in the graph on water consumption in the four treatment groups showed single peaks, and that the curves reached their maximums in July and their minimums in February. (2) Water evaporation of soil used for planting poplar accounted for 15.9% of the total water consumption in steady-state situations annually. The background loss accounted for 30.4% of the total water consumption. (3) Water consumption of poplars under surface covering accounted for 53.7% of the total water consumption, and the annual change curves also had single peaks. Furthermore, the total water loss of soil in which poplars were planted was 2.77 times more than that of soil without poplar. The total water evaporation of soil on bare land in which poplars were planted was 7.9% higher than that of soil on bare land without poplar. (4) The average transpiration rates of leaves of poplars under surface covering and on bare land were 30.8 and 9.5 g cm^-2 a^-1, respectively, whereas the average water consumption per gram of biomass was 39.61 g. These results indicate that poplars have a strong water-seeking capacity and high transpiration rate; therefore, planting poplar will cause significant soil moisture loss in afforestation areas, resulting in the desiccation of deep soil and limited regulation of soil water storage in this area.