松嫩盐碱草地植物种群的土壤营养位季节动态

针对松嫩盐碱草地的特点,综合评价了18项土壤因子,以植物的相对地上生物量为土壤营养位效能,分析了松嫩盐碱草地植物种群的土壤营养位季节动态。伴随季节的更替,碱蓬等强耐盐碱植物的土壤营养位中心点逐渐向土壤盐碱程度严重的一侧移动,土壤营养位体积也逐月增加,土壤营养位宽度的扩大是土壤营养位体积增加的主要原因。虎尾草(Chloris virgata)和羊草(Aneurolepidium chinense)的土壤营养位中心点数值和土壤营养位体积7月份时最大。7月份时虎尾草的土壤营养位效能峰值明显高于其它月份的,使得虎尾草此月份的土壤营养位体积在整个生长季内最大,而羊草7月份的土壤营养位宽度和土壤营养位效能峰值都较大,共同决定了该月份羊草的土壤营养位体积最大。除上述植物外,其他轻度耐盐碱植物的土壤营养位中心点随季节更替的变化趋势与碱蓬等强耐盐碱植物的刚好相反,是向土壤盐碱程度越轻的方向。其他轻度耐盐碱植物的土壤营养位宽度8月份时最小,但因为此时土壤营养位效能峰值明显高于其它月份的,它们8月份的土壤营养位体积仍是整个生长季内最大的。松嫩盐碱草地植物种群土壤营养位重叠也存在着明显的季节变化。

Seasonal dynamics of soil nutrition field for plants in Songnen alkaline grassland

Plant biomass and soil nutrition both directly influence Soil Nutrition Field (SNF), and change with season. Therefore the SNF can be used to detect the relationship between plant distribution and soil nutrition. According to the characteristics of Songnen alkaline grassland, eighteen soil factors were surveyed to evaluate soil nutrition status with principal component analysis. Seasonal dynamics of the SNF were calculated for several common species in terms of relative aboveground biomass as SNF efficiency. As the season changing, the SNF center of the species with high tolerance to saline-alkaline soil, such as Suaeda salsa L., moved toward the serious alkalization side, and the volume of the SNF became larger as the widening of the SNF breadth. For Chloris virgata and Aneurolepidium chinense, the center and the volume of the SNF both reached the peaks in July. The SNF efficiency index peak of C. virgata was significantly higher than that in other months, because its SNF volume was largest in July in the whole growing season. For A. chinense, the SNF breadth was wider and the efficiency index peak of the SNF was higher, which caused the largest volume of the SNF in July. The SNF centers of the other weak saline-alkaline tolerant species moved to lighter alkalization side, and the largest volumes of the SNF were occurred in August since the efficiency index peak of the SNF was notably higher than that in other months, even though the SNF breadth was the narrowest at the time. Moreover, the SNF overlaps of the plant populations also behaved differently along seasons in Songnen alkaline grassland.