黑岱沟露天矿区排土场2种典型植物的水分来源及利用策略

论文利用稳定性同位素示踪技术,分析排土场2种典型植物水分来源的差异及水分利用策略.结果表明,黑岱沟矿区大气降水的氢,氧同位素含量均落在中国大气降水的变化范围之内,不同月份大气降水的δD(δ¹⁸Ο)值表现出明显的降水量和季节效应.旱季小叶杨主要利用10 cm土层以下的水分,对100~150 cm土层水分利用率最高,达25.6%;沙棘对各层次土壤水分的利用比例接近,差异不明显,对表层土壤水分的利用最高,达26.5%;为了避免种间竞争,小叶杨很少利用表层(0~10 cm)土壤水分.雨季小叶杨主要利用表层和浅层土壤水分,利用比例高达70.9%,沙棘主要利用30~60 cm土层的水分,达73.5%,其次是10~30 cm土层,达17.4%.两种不同生活型植物通过不同策略合理利用旱季有限的水分,而在雨季水分供给充分时,均优先利用浅层水源,使其组成的生态系统更好地适应矿区排土场脆弱的生态环境.

Water Use Patterns of Two Typical Plants Based on Hydrogen and Oxygen Stable Isotopes at Dumping Site in the Opencast Coal Mining Area of Heidaigou

The stable isotope tracer technique was used to analyze the water sources and their seasonal changes of two plants (Populus simonii and Hippophae rhamnoides) with different life forms, and IsoSource Model was used to determine the probable contribution of certain soil-layer water source to total water uptake of plants. The result showed that δD and δ¹⁸Ο in rainfall water are in significantly negative correlation with the amount of precipitation, and there are obvious seasonal variation of δD (δ¹⁸Ο) values. In the dry season (March-June), hydrogen isotopic composition is enriched and the value of δD (δ¹⁸Ο) is higher; in the wet reason ( July-September) when rainfall events are frequent, the δD (δ¹⁸Ο) value in rainfall water deplete. In the dry season, Populus simonii uses soil water largely from the 10-150 cm layer, 25.6% of which is from the 100-150 cm layer. Hippophae rhamnoides uses soil water from all the soil layer (0-150 cm), 26.5% of which is from the surface layer (0-10 cm). Populus simonii does not used soil water from the 0-10 cm layer that avoids the inter-specific competition with Hippophae rhamnoide. In the wet season, two species both absorb water from shallow layers (0-60 cm). Populus simonii uses more than 70.9% of water from the 0-60 cm layer, and Hippophae rhamnoides uses more than 73.5% of water from the 30-60 cm layer. These findings indicated that two species utilize rationally the limited soil water in dry season by the different strategies, and use preferentially the shallow soil water when the soil water supply is adequate in wet season, which makes it much easier for them to be adaptive to the fragile ecological system in opencast coal mining area. The research will be useful for vegetation reconstruction in the opencast coal mining area.