枯落物输入变化条件下云南松林地土壤呼吸特征研究

Soil Respiration in Pinus yunnanensis Forest with Alterations in Litter Inputs

于2018年1月采用枯落物添加和去除实验,在滇中高原磨盘山的云南松林设置对照(CK)、去除枯落物(NL)、双倍枯落物(DL)、去除根系(NR)、去除地上枯落物和地下根系(NI)和去除有机层和A层(O/A-Less)6个处理,对不同处理林地土壤呼吸速率(R_(s))和不同土壤细菌(SBP)、真菌(SFP)、放线菌(SAP)的数量以及土壤脲酶(URE)、过氧化氢酶(CAT)、磷酸酶(ACP)、蔗糖酶(INV)和蛋白酶(PRO)的活性进行野外定位观测及实验室测定。结果显示:(1)不同处理不同时间土壤呼吸速率差异显著,不同处理年均土壤呼吸速率依次为R_(s(DL))>R_(s(CK))>R_(s(NL))>R_(s(NR))>R_(s(O/A-Less))>R_(s(NI))。(2)不同处理土壤微生物数量均以0~10 cm土层最多,并随深度增加而减少;在20~60 cm土壤层中,无根系处理的土壤微生物数量均比有根系处理低;不同土壤深度的土壤微生物数量均以DL处理土最高。(3)不同深度的CAT活性以DL最高,其余酶活性以CK处理最高;但不同土壤深度的土壤酶对枯落物输入变化的响应不尽相同。(4)20~60 cm层的SAP数量与R_(s)相关性不显著(P>0.05),其余土壤微生物与R_(s)呈极显著相关(P<0.01),但相关程度有所差异。5种土壤酶中,0~10 cm层和40~60 cm层的PRO与R_(s)相关性不显著(P>0.05),其余土壤酶与R_(s)相关性呈极显著(P<0.01)或显著(P<0.05)。可得结论:土壤微生物及酶活性在土壤呼吸中起着至关重要的作用,不同枯落物处理对土壤微生物及酶活性产生不同程度的影响,进而协同作用于土壤呼吸。

The Detritus Input and Removal Treatment(DIRT)was used in January 2018 in the Pinus yunnanensis forest in Mopan Mountain,Central Yunnan Plateau.Set up normal litter(CK),double litter(DL),no litter inputs(NL),removal of organic and A-layer(O/A-Less),no roots inputs(NR),no litter and root inputs(NI),For each treatment,the soil respiration rate(R_(s))under different treatments,the number of soil bacteria(SBP),fungi(SFP),actinomycetes(SAP);soil urease(URE),catalase(CAT),phosphoric acid Enzyme(ACP),invertase(INV)and protease(PRO)activity were observed in the field and determined in the laboratory.The results showed that:(1)The difference of soil respiration rate between different treatments and different practices is significant.The average annual soil respiration rate of different treatments is R_(s(DL))>R_(s(CK))>R_(s(NL))>R_(s(NR))>R_(s(O/A-Less))>R_(s)(NI).(2)The number of soil microorganisms in different treatments was the most in the 0-10cm layer,and decreases with the increase of depth;in the 20-60 cm soil layer,the number of soil microorganisms in the soil without roots was lower than that with roots;soils with different soil depths The number of microorganisms was highest in DL-treated soil.(3)The activity of CAT at different depths was highest in DL,and the activity of other enzymes was highest in CK treatment;but the response of soil enzymes at different soil depths to changes in litter input was different.(4)The number of SAP at 20-60 cm layer was not significantly correlated with R_(s)(P>0.05),and the remaining soil microorganisms are extremely significantly correlated with R_(s)(P<0.01),but the degree of correlation was different.Among the 5 soil enzymes,the correlation between PRO and R_(s) in the 0-10 cm layer and 40-60 cm layer was not significant(P>0.05),and the correlation between the other soil enzymes and R_(s) was extremely significant(P<0.01)or significant(P<0.05).In summary,soil microbial and enzyme activities play a crucial role in soil respiration.Different treatments have different degrees of influence on soil microorganisms and enzyme activities,and then synergistically act on soil respiration.