科尔沁沙地南缘樟子松固沙林更新迹地土壤理化特性演变研究

科尔沁沙地南缘在90年代初引种失败后,对原有植被采伐并在采伐迹地进行植被重建。为了研究沙地植被更新13 a后土壤特性,选取土壤容重、有机质、全氮、全磷、全钾、碱解氮、速效钾7个衡量土壤肥力的重要指标作为土壤环境肥力质量的评价指标,采用改进的内梅罗(Nemoro)公式对山杏、彰武小钻杨和白丁香三种林分的土壤环境肥力质量进行综合评价。结果表明,植被重建后土壤特性演变朝良性方向发展,相较于采伐迹地土壤容重减小、田间持水量提高;有机质、氮磷钾及其有效性明显提高,有效磷和碱解氮含量相较于采伐迹地增幅最大;3种植被重建类型对提高土壤上层(0~10 cm)理化性质的能力较下层(10~20 cm)强;樟子松更新迹地3种植被重建类型下土壤肥力质量综合排序为:彰武小钻杨(0.82)白丁香(0.72)山杏(0.66)。樟子松固沙林更新迹地植被重建后的土壤理化性质及肥力条件得到了有效改善,且有很大的提升空间。研究结果将为今后科尔沁沙地生态恢复提供科学依据。

Evolution of Soil Physicochemical Characteristic in Regeneration Site with Pinus sylvestris var.Mongolica in the South Edge of Horqin Sandy Land

The southern edge of Zhangwu County is one of the most serious desertification areas in Liaoning Province.In order to study soil characteristics after 13 years of vegetation reconstruction in the regeneration site in Horqin Sandy Land with Pinus sylvestris var.mongolica,this paper took soil bulk density,organic matter (SOM),total nitrogen (N),total phosphorus (P),total potassium (K),alkaline N and available K as evaluation indices and comprehensively evaluated soil fertility quality in Prunus sibirica,Syringa oblata var.affinis and Populus × xiaozhuanica using the improved Nemoro formula.The results showed that after vegetation reconstruction,soil characteristics evolved well:soil bulk density was lowered,and soil field capacity,the contents of SOM,total N,P and K and available P and alkaline N significantly increased compared with in cutover land.The reconstruction with 3 types of vegetation more strongly improved soil field capacity and SOM content at the upper layer (0-10 cm) than at the lower layer (10-20 cm).Comprehensive index of soil fertility quality decreased after 3 types of vegetation reconstruction in regeneration site of Pinus sylvestris var.mongolica following the order of Populus × xiaozhuanica W.Y.Hsuet L.cv.Zhangwu (0.82) ＞ Syringa oblata var.affinis (0.72) ＞ Prunus sibirica (0.66).In a word,vegetable regeneration in regeneration site with Pinus sylvestris fixing sand greatly improved soil physichemical properties and soil fertility quality.The research results would provide a scientific basis for the ecological restoration in Horqin sandy land.