水保所知识产出(1956---)知识库

黄土高原地区是典型生态脆弱地区，同时也是我国重要的煤炭基地，煤炭开
采中形成了大面积的露天煤矿排土场，排土场体积巨大改变了原有地貌，且重构
土壤养分贫瘠、土壤结构性差、植被覆盖度低，极易引发水土流失等生态环境问
题，因此排土场治理对于该地区生态安全有重要意义。植被恢复是退化土壤生态
修复普遍采用的措施，对于黄土区植被恢复已经积累了大量理论技术，而露天煤
矿排土场为重构土体，其土壤性质与自然地貌土壤有很大差异，目前对于该地区
排土场重构土壤长时间植被恢复下土壤环境效应及影响因素还不清楚。本文以不
同植被恢复措施下黄土区露天煤矿排土场为主要研究对象，采用野外调查和和室
内分析相结合的方法，研究了植被恢复对排土场重构土壤养分性质和土壤结构的
影响，并筛选适宜于排土场的植被恢复措施，探讨了黄土区露天煤矿排土场的植
被恢复土壤环境效应。主要研究结论如下：
（1）经过 15 年植被恢复，排土场土壤养分含量有了显著的提升，其中植被
恢复对表层土壤养分提高较明显，而对次表层土壤养分影响较小，土壤养分表现
出明显的表聚。土壤有机质和氮素对植被恢复响应较敏感，植被恢复下表层土壤
有机质、全氮和碱解氮含量分别达到 6.12 g/kg，0.27 g/kg 和 21.89 mg/kg，但其
含量水平仍然较低，土壤有机质和氮素含量低是植被生长的限制性因素，需要进
一步熟化培肥；土壤表层速效磷含量达到 6.56 mg/kg，含量相对较高，但有减小
趋势，长时间植被恢复下土壤磷素可能出现耗竭；排土场土壤速效钾含量水平高，
土壤表层含量达到 135.08 mg/kg，且植被恢复下有一定提高。不同植被恢复模式
相比，草地土壤养分含量显著高于灌木和乔木。土壤有机质与土壤全氮、碱解氮、
速效钾表现出极显著（P<0.01）的线性正相关，有机质可以作为排土场土壤肥力
的主要指标。从提高土壤培肥角度，排土场植被恢复早期应以草地作为主要植被恢复模式，然后采用林草结合模式提高排土场群落结构功能和稳定性，矿区植被
恢复中有机质和氮磷亏缺是重要的限制因素。
（2）植被恢复促进了排土场水稳性团聚体的形成，改善了土壤结构。平台
0~20 cm 土层水稳性大团聚体数量（R0.25）、平均重量直径（MWD）和几何平
均直径（GMD）分别达到 31.1%，0.70 mm 和 0.26 mm，边坡分别达到 13.3%，
0.37 mm 和 0.17 mm，均显著高于裸地，分形维数（D）在平台和边坡分别为 2.91
和 2.96，均显著低于裸地；平台土壤团聚性要好于边坡，草地对于平台土壤团聚
结构改良效果较好，而灌木对于边坡改良效果较好；排土场土壤有机碳和粘粒含
量均与土壤团聚体指标有显著正相关性。植被恢复提高了排土场土壤团聚性，植
被恢复类型和地形对排土场土壤团聚体特征有显著影响。
（3）排土场人工草地对土壤有机碳、养分和团聚体状况都有较好的改良效
果，其中表层与原地貌已经较为接近，而深层还需要进一步熟化改良。不同类型
人工草地中苜蓿对土壤改良效果最好，但其耗水严重，对深层土壤改良效果较差，
从改良排土场土壤质量角度在恢复初期应以苜蓿作为主要人工草地类型培肥土
壤，但在一定阶段应引种冰草等耗水较少的其它草本，增加群落稳定性，减缓群
落退化和土壤干层的形成，对排土场进行持续的生态恢复和土壤改良。
关键词：黄土区；排土场；植被恢复；土壤养分；土壤团聚体

The Loess Plateau region is a typical fragile area of ecology as well as the most
important coal production base of our country. The dump is forming in the processing
of coal-mining production，which has special poor soil, loosely slope, a extremely low
vegetation coverage and will easily bring about a series of ecological and environment
problems, especially the soil erosion. Therefore ecological management of dump has
important implications for ecological security in this area. Vegetation restoration is the
fundamental management to construct ecological environment in the ecological
degradation region and many theories and techniques about vegetation restoration in
Loess Plateau have come to being, but few research work had been done on
vegetation restoration of mining area on the Loess Plateau. In this paper, by the
method of soil sampling and laboratory analysis, the effects of vegetation restoration
on soil nutrients and soil structure of opencast coal mine dump on the Loess area have
been researched. We explored the effects of vegetation restoration on soil environment
of reconstructed soil of opencast coal mine dump in loess area and the results are as
follows:
（1）There was a significant increase in soil fertility of dump through fifteen
years of vegetation restoration. Soil organic matter, total N and available N had
significant increase but they still at lower level and far below the content of original
landform soil. Available P of dump was higher than original landform soil but had a
decreasing tendency with vegetation restoration. The soil of dump under vegetation
restoration was rich in available K which was still increasing with revegetation.
Vegetation types had significant influences on soil nutrient and the nutrient content in  grassland was obvious higher than in shurbland and woodland. The influence of
vegetation on the surface 0~10 cm soil nutrient was greater than that on the deep
10~20 cmoil, also the soil nutrient was to surface enrichment under the action of
vegetation. The content of organic matter had a linear positive correlation with the
total N, available N and available K in 0~10 cm soil layer. Therefore soil organic
matter could be selected as a primary index for evaluating soil fertility. In terms of
improving soil fertility, it was better to select grassland as the main vegetation type in
early restoration in dump and then combined grass with tree to maintain soil fertility
and the stability of plant community. Soil organic matter, nitrogen and phosphorus
deficiency was the limiting factor in vegetation restoration on coal mine dump in the
Loess area.
（2）The R0.25, MWD and GMD of 0~20 cm soil layer were significantly
increased in revegetation land than that in abandoned land on both platform and slope.
The R0.25, MWD, GMD and D in 0~20 cm soil layer of revegetation land were
31.1%, 0.70 mm, 0.26 mm and 2.91 respectively on platform, and 13.3%, 0.37 mm,
0.17 mm and 2.96 respectively on slope. The soil aggregates quality was better on the
platform than on the slope. Artifical grassland had a more significantly improvement
for soil aggregates quality than the shrubbery on the platform of dump. While on the
slope, the shrubbery was better than the artifical grassland. The soil aggregates quality
was lower in surface layer than sub-surface layer on the platform. Soil organic carbon
content and soil clay content were significantly related to soil aggregate quality. Our
results suggested that soil aggregates quality was improved significantly after 15 years
of vegetation restoration, and vegetation types and landforms had significant
influences on soil aggregates properties in this studied mining area on the Loess
Plateau.
(3) Artificial grassland reconstruction improved SOC, nutrient and soil
aggregates quality significantly. The soil quality in surface soil layer had been near the
level of original landform soil but in deep soil layer was still in a poorer conditions.
Improvement on soil environment of Medicago sativa was the best in different
grassland but it had a low effect on deep soil layer and tend to degradation at the later  stage of revegetation due to its strong consumption of soil water. It was better to select
grassland as the main vegetation type to fertilize soil in early restoration in dump and
then combined with other grass community with low water consumption, which could
improve the stability of plant community and improve soil quality continuously.
Key words: Loess area, Dump, Revegetation, Soil fertility, Soil aggregate