Abstract: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.