东部草原露天矿区粘土改良模拟研究

以我国东部草原露天矿区粘土为研究对象,采用盆栽试验方法,以粘土与表土和沙土混合物为培养基质,三叶草(Trifolium repens Linn)为供试植物,研究不同比例下三叶草生物量、养分吸收量、土壤理化和生物学性状的差异,为寻找最佳配比提供依据。结果表明:不同混合比例显著影响三叶草生物量,粘土+表土(1∶1、1∶2和1∶3)生物量最高(26.5—40.0 g/盆),平均为31.2 g/盆,粘土+沙土(1∶1、1∶2和1∶3)次之(14.9—20.3 g/盆),平均为18.9 g/盆,粘土、沙土和表土平均分别是9.0、5.4 g/盆和41.7 g/盆,同样地,粘土+表土混合基质上三叶草氮吸收量平均为1071 mg/盆,分别是粘土+沙土、粘土和沙土氮吸收量660、321 mg/盆和190 mg/盆的1.62、3.34倍和5.64倍,磷和钾吸收量具有相似变化规律,这与三叶草根直径、根长、根表面积和根尖数有显著关联性;粘土和表土与粘土和沙土混合基质的容重和最大持水量分别显著下降7.4%—21.5%和24.5%—71.8%,饱和入渗率、孔隙度和标准化平均重量直径分别显著增加26.9%—96.3%、45%—218%和34%—72%;全氮、有机质、速效磷、速效钾、饱和电导率显著增加23.0%—88.3%、25.1%—146%、44.0%—91.5%、70.3%—114.8%和3.5%—59.3%;磷酸酶、脲酶、蔗糖酶、硝酸还原酶和固氮酶活性显著提高45.5%—105%、65.2%—172.3%、160%—252%、53.4%—62.7%和197%—374%;真菌、细菌和放线菌数量增幅为119%—142%、93.5%—107%和83%—147%。相关性分析表明,生物量与土壤理化性状、酶活性和微生物数量呈显著或极显著正相关,表现为粘土+表土=表土粘土+沙土粘土沙土。因此,表土或沙土均能改良粘土性状,其中粘土和表土1∶2配比效果最优。

Substrate compositions facilitate clay restoration of the simulation study in an opencast coal mine in the eastern steppe of China

A pot experiment was conducted to study the differences between clovers (Trifolium repens Linn) in biomass, nutrient uptake, physical, chemical, and biological properties of substrates among various mixtures with clay, topsoil, or sandy soil, in order to obtain the optimal mixture ratio. The results showed that the substrates with different mixture proportions significantly influenced clover productivity; the biomass varied with the type of substrate and was in the range of 26.5-40.0 g/pot (average=31.2 g/pot) for the clay and topsoil combinations and in the range of 14.9-20.3 g/pot (average=18.9 g/pot) for the clay and sandy soil combinations; the biomass was 9.0 g/pot, 5.4 g/pot, and 41.7 g/pot for the clay, sandy soil, and topsoil, respectively. Similarly, the highest N acquisition was 1071 mg/pot of clover in the clay and topsoil combinations, which was 1.62, 3.34, and 5.64 times higher for the clay and sandy soil combination, clay, and sandy soils, as were P and K acquisition, which was significantly altered by the difference in root diameter, root length, root surface area, and tip numbers. In comparison with the clay and sandy soil, the soil bulk density and maximum moisture holding capacity were significantly decreased by 7.4%-21.5% and 24.5%-71.8%, respectively, whereas the infiltration rate, porosity, normalized mean weight diameter, total N, organic matter, Olsen P, available K, electric conductivity of the clay with topsoil and clay with sandy soil combination were markedly enhanced by 26.9%-96.3%,45%-218%, 34%-72%, 23.0%-88.3%, 25.1%-146%, 44.0%-91.5%, 70.3%-114.8%, and 3.5%-59.3%; the activities of phosphatase, urease, nitrate reductase, invertase, and nitrogenase were significantly increased by 45.5%-105%, 65.2%-172.3%, 160%-252%, 53.4%-62.7%, 197%-374%; the numbers of fungi, bacteria, and actinomycetes were also increased by 119%-142%, 93.5%-107%, and 83%-147%, respectively. Significant positive correlations were observed between clover productivity and soil physicochemical or biological properties via correlation analysis; overall, the effect of substrates occurred in the order clay+topsoil=topsoil > clay+sandy soil > clay > sandy soil. Thus, the clay and topsoil or sandy soil mixtures provided significantly enhanced substrate conditions; in particular, the 1:2 clay and topsoil ratio was the optimum choice in the opencast coal mine in the eastern steppe of China.