Soil moisture is a key driving factor that affects vegetation growth.Vegetation reacts to soil moisture through processes such as evapotranspiration.In-depth exploration of the interaction between soil moisture and vegetation GPP is crucial to ensuring the sustainable development of ecosystems and the efficient utilization of water resources.This study employed MODIS GPP,ERA5-Land soil moisture,and other data sources.It utilized an enhanced nonlinear Granger causality model,along with partial correlation analysis,Sen's slope,and the Mann-Kendall method.These methods were used to examine the combined changes in GPP and soil moisture and their mutual feedback relationship across diverse vegetation types in China from 2000 to 2021.The results showed that:(1)Since 2000,50.89％-57.61％of the vegetated areas in China have shown a synergistic trend of increasing GPP and decreasing soil moisture,which exhibited a greater proportion with increasing soil depth.The proportion of areas with consistently increasing trends in both GPP and soil moisture was 39.03％-45.76％.(2)In 59.88％-79.38％of vegetated areas,both GPP and soil moisture showed a bidirectional Granger causal relationship.This proportion decreased with soil depth,notably in temperate grassland areas(R6)and temperate desert regions(R7).(3)The increase in GPP resulted in a more significant consumption(57.03％)of soil moisture at 100-289 cm depth and a longer lag effect(2.15 months).Soil moisture at a depth of less than 100 cm mainly promoted the increase in GPP(71.43％-76.58％)and only showed inhibitory effects in some areas,such as the Tianshan Mountains and Hengduan Mountains.The promoting effect of soil moisture at 100-289 cm depth on the vegetation GPP(48.31％)weakened and was accompanied by a significant increase in the lag effect(2.92 months).(4)As the precipitation increased,the interaction between vegetation GPP and soil moisture gradually decreased.When the precipitation was between 200 mm and 400 mm,the interaction was most significant.The influence of different temperature gradients on the interaction between vegetation GPP and soil moisture exhibited multiple threshold effects.This study helps to deepen our understanding of the interaction between carbon and the water cycle of the terrestrial ecosystem in the context of climate change.It also provides an important theoretical reference for the implementation of future ecological restoration projects and the sustainable development of ecosystems.
维普
万方数据