跨地带土壤置换实验研究

以温带针阔混交林暗棕壤地带内的白浆土、草甸土、泥炭土为原料,以长白山自然保护区内的寒温带山地棕色针叶林土为置换对象,完成了仿自然原型的土壤合成,进行了跨地带的土壤置换与植被生长实验研究。结果表明:①山地棕色针叶林土的腐殖质层厚度、酸度和速效氮含量为植被生长的限制性因子;②合成土壤理化指标必须以原生土壤限制因子拐点(值)指标为确定依据,作为合成土壤的关键性指标;③在长白山采用泥炭土与草甸土各占1/4,白浆土占1/2进行混合,土层厚度40cm,并使用石灰进行调酸达到中性后,植被恢复效果最好、造价最低。

The experimental study on trans-regional soil replacement

When people did ecological restoration, it was very difficult to achieve the trans-regional soil replacement. Basalt platform is distributed around the Changbai Mountain Nature Reserve. The intrazonality soil (i.e. baijiang soil, peat soil and meadow soil) in the temperate humid climate zone is developed widely on basalt platform, howerer, the zonality soil such as dark brown earth is rare. The mountain brown coniferous forest soil, baijiang soil, peat soil and meadow soil are not in the same physical geographic zone, and there are significant differences in their physical and chemical properties, thus, it is not easy to complete soil replacement directly. In this zone, we could use the synthesis soil which is artificially synthesized with baijiang soil, peat soil and meadow soil to instead of the mountain brown coniferous forest soil. In this study, the baijiang soil, peat soil and meadow soil in the dark brown soil zone in the temperate broadleaved-coniferous mixed forest were used as raw materials, and the mountain brown coniferous forest soil in cold temperate zone in Changbai Mountain Nature Reserve was used as replacement object. Firstly, we completed soil synthesis taking the imitates the natural prototype principle, and then, conducted the experimental research on trans-regional soil replacement and plant growth. The results showed that the differences of soils were significant in the distribution of the content of every soil grain size group (%), humus layer thickness (10-20 cm), pH (5.9-7.5), and the available nitrogen (N) content (57.8-100.7 g/kg) in the mountain brown coniferous forest soil zone. The limited factors of plant growth were humus layer thickness, pH, and available N content of mountain brown coniferous forest soil. Plant growth condition was better as the humus layer thickness was 40cm, pH was 7.0 and available N content was 80 mg/kg which were the inflection point value of the mountain brown coniferous forest soil limited factors. Therefore, the inflection point value of the mountain brown coniferous forest soil limited factor was a key to synthesis soil, and it was the basis for physical and chemical indicators of synthesis soil. There were more gravel but less silt and clay on surface soil of the mountain brown coniferous forest soil, the soil texture is gravelly sandy loam. Soil texture of meadow soil was sandy loam soil. There were less gravel but more silt and clay on surface soil of soil texture of baijiang soil, and peat soil was loam. The mountain brown coniferous forest soil and the peat soil were more abundant in organic matter content, however, the baijiang soil and the meadow soil were low. The pH of the mountain brown coniferous forest soil was higher than that of baijiang soil, peat soil and meadow soil. Total N was more abundant in the mountain brown coniferous forest soil than that of other types of soils, but the available N was lower in surface soil of the mountain brown coniferous forest soil. The total and available potassium was the most abundant nutrient in the mountain brown coniferous forest soil. There was no significant different in the total and available phosphorus for the four types of soils. In Changbai Mountain, the mixed soil was made of a quarter of peat soil, a quarter of meadow soil and a half of baijiang soil and the its soil layer thickness was kept about 40 cm, then the pH of the mixed soil was adjusted to neutral by lime. It was the most reasonable solution for replacing the mountain brown coniferous forest soil since the vegetation restoration effect was best and the cost was the lowest to produce the mixed soil.