The Response Of Glomerin-related Soil Protein In Coniferous And Broad-leaved Mixed Forest To Nitrogen Increase And Water Reduction

Glomalin-related soil protein(GRSP)is an important index for evaluating and indicating the dynamic changes of soil carbon(C)pool and soil stability.Previous studies have confirmed that changes in nitrogen deposition and precipitation patterns can have direct or indirect effects on GRSP in different ways,cover richness,plants community composition,land use system and soil nutrient status.Based on the importance of GRSP in soil C pool,it is important to understand the mechanism of GRSP change under the background of increasing atmospheric nitrogen(N)deposition and changing precipitation pattern for clarifying the driving factors of soil C cycle.In addition,our understanding of the seasonal trend of GRSP behind the current increase in atmospheric nitrogen(N)deposition and precipitation pattern is not very clear.Based on this,we established an experiment of nitrogen and water reduction in coniferous and broad-leaved mixed forest in Changbai Mountain to explore the seasonal trend of GRSP under the background of climate change.The results show that the responses of all GRSPs to the experimental treatments are different in different soil layers.For easy-to-extract balloon mycin(EE-GRSP),TR significantly reduced the content of EE-GRSP in 0-10 cm soil layer compared with CK(P<0.05),and showed alike status in All the months.Under N50 conditions,EE-GRSP showed the opposite result as TR,and showed an upward trend in different months compared with CK,TR-N50 treatment promoted plant growth in July and August,and inhibited plant growth in the rest of the month.In addition,EE-GESP of all treatments in 0-10 cm soil layer had the same time-varying trend.which demonstrates that the content in June is low.With the increase of temperature in July and August,the plant growth is vigorous and other factors make the content reach its peak.At the end of the growing season in September and October,the growth activities of some rows of plants slowed down,and the nutrients transported to the roots were reduced,which reduced the production of EE-GRSP by AMF and reduced its content in soil;TR promoted the content of EE-GRSP in 10-20 cm soil layer;N50 appeared in July and August to promote the inhibition of the rest of the month;TR-N50 did not show obvious regularity in different months.Trend of change.The seasonal variation trend of all treatments is the same as that of 0-10 cm soil layer,but the range of peak value and decline is obviously greater than that of 0-10 cm soil layer.By comparison,TR treatment in June-September decreased the content of T-GRSP than CK in 0-10 cm soil layer,but the extent gradually decreased.Water reduction in October was no longer a limiting factor for T-GRSP accumulation,but showed a significant role in promoting it(P>0.05);N50 significantly increased the content of T-GRSP in June and October(P<0.05),but the effect of TR-N50 on T-GRSP was similar to that of N50 in the other months.But the content of T-GRSP was less than that of N50 treatment.Under all treatments,the seasonal dynamics of T-GRSP content showed as follows: 6 < 7 < 8 <9 <10,and the Trend mitigationand finally tended to be flat.In 10-20 cm soil depth,the response of T-GRSP to different treatments showed consistency in different months.All treatments in 10-20 cm soil layer showed inhibition to T-GRSP,i.e.TR < TR-N50 < N50 < CK.All treatments express the uniform trend of change.There was a significant linear correlation between GRSP and soil organic matter,EE-GRSP and T-GRSP under different treatments(P<0.05),and the correlation between EE-GRSP and soil organic matter was stronger than that of T-GRSP.The above results showed that GRSP showed different responses to different treatments,and different growth stages of plants were the key factors affecting GRSP content.Especially,the response of EE-GRSP to different treatments and seasonal dynamics is very obvious.At the same time,it is proved that GRSP and soil C pool dynamics have significant consistency,indicating that the dynamic changes of GRSP have an important indicator role in soil C cycle.