三江源区不同建植年限人工草地根系动态特征

根系动态特征能够反映人工草地植物利用土壤资源的效率和群落恢复演替的程度.本研究以三江源区不同建植年限(5、6、9和13年)人工草地植物根系为研究对象,利用"微根管"技术,连续两个生长季(2015年5-9月和2016年5-9月)探究了4个建植年限人工草地根系动态特征.结果表明:地上生物量和丰富度在建植5～9年呈下降趋势,...

Root dynamics of artificial grassland for swards of differing ages in the'Three-River Source'region

In artificial grassland,measurement of root dynamic traits can indicate the efficiency of the vegetation in using soil resources and the progress of plant community restoration and ecological succession.In this study,the root dynamics of artificial grassland established 5,6,9 and 13 years previously was investigated in the Three-River Source region.Data were collected for two consecutive growing seasons(May-September 2015 and May-September 2016),utilizing minirhizotron in situ monitoring technology.The results showed that the aboveground biomass and species richness decreased from 5 to 9 years and increased from 9 to 13 years.The soil physiochemical properties similarly changed in a“N”shape over the time series and the differences between different sward establishment years was significant.The majority of root growth and death occurred in the 0-10 cm soil depth,and root longevity,cumulative production and cumulative mortality all fluctuated across the time series of establishment dates.The average root standing crop continued to increase with increase in years established,and numbers of deep roots observed increased between 6 and 9 years after establishment.There were obvious seasonal changes in root production,mortality and standing crop.The growth peak was in June,the standing crop peak was in July,and the death-rate peak was in August,while the seasonal root growth peak of artificial grassland established for 9 years was later than in grassland of other ages.The number of years established and the soil depth directly affected root longevity,and other environmental factors indirectly affected root standing crop by influencing soil available nutrients or aboveground biomass.In summary,planting artificial grassland can promote the soil quality and increase the aboveground biomass,richness and root standing crop.The secondary degradation of planted artificial grassland from 6 to 9 years after establishment is only a temporary transitional stage.Therefore,at this stage,the establishment of suitable artificial management measures can ensure the stability of the soil nutrient status and accelerate the process of plant community succession,thereby improving the vegetation community stability and resilience of artificial grassland.