阴山北麓不同恢复年限弃耕地植物群落生物量与土壤养分变化

Changes of Plant Community Biomass and Soil Nutrients in Abandoned Farmland in Different Restoration Years at the Northern Piedmont of Yinshan Mountain

以阴山北麓不同自然恢复年限(5年、15年、20年)弃耕地为对象,以天然草地为对照,测定群落地上和地下生物量以及土壤全氮、全磷、有机碳含量等指标,探究弃耕地演替过程中植物群落、土壤养分的变化以及相互影响。结果表明:随弃耕年限的增加,多年生禾本科植物种类不断增加;弃耕地自然恢复过程中,地上生物量在弃耕第5年最高,其次是弃耕20年,弃耕15年最低;地下生物量随弃耕年限的增加而显著增加(P<0.05);总生物量随弃耕年限增加呈上升趋势,但均低于天然草地;土壤有机碳和全氮含量逐渐增加,有机碳含量在弃耕20年后仍显著低于天然草地(P<0.05),土壤全氮在弃耕20年显著高于天然草地(P<0.05),土壤全磷仅在弃耕5年高于天然草地且有显著差异(P<0.05)。弃耕过程中,植被演替促进了土壤养分的积累,植物群落生物量变化受土壤养分的影响较小。

In this experiment,abandoned farmland with different natural restoration years(5 years,15 years and 20 years)at the northern piedmont of Yinshan mountain was taken as the object,and natural grassland was used as the control to measure the aboveground and underground biomass,soil total nitrogen,total phosphorus and organic carbon,and explore the change and mutual effects of plant communities and soil nutrients during the succession of abandoned farmland.The results showed that with the increase of abandoned farming years,the species of perennial grasses increased continuously.During the natural recovery process of abandoned farmland,the aboveground biomass was the highest in 5 years of abandoned farmland,followed by 20 years of abandoned farmland,and the lowest in 15 years of abandoned farmland;the underground biomass increased significantly with increase of abandoned years(P<0.05);the total biomass increased with the increase of abandoned years,but was lower than that of natural grassland;the content of soil organic carbon and total nitrogen increased gradually,the content of organic carbon was still significantly lower than that of natural grassland after 20 years of abandonment(P<0.05),while the content of soil total nitrogen was significantly higher than that of natural grassland after 20 years of abandonment(P<0.05),the content of soil total phosphorus was only higher than that of natural grassland after 5 years of abandonment(P<0.05).During the abandonment process,vegetation succession promoted the accumulation of soil nutrient content,and the change of plant community biomass were less affected by soil nutrients.