Effects of trenching on soil processes and properties in a New Mexico mixed-conifer forest

摘要

Trenching was used to reduce root activity in treeless plots in a New Mexico mixed-conifer forest to examine the effects of plant roots on soil processes. Trenching led to increases in moisture content (104), inorganic N concentration (115), and mass loss from cellulose (196). In laboratory incubations, trenched soils collected in the 1st and 2nd year after trenching evolved 52 and 115 more CO2, respectively, than control soils. Amending incubated trenched and control soils with moisture and inorganic N indicated that increased soil moisture content in trenched plots could explain the increased microbial activity. Trenching also had statistically significant but inconsistent effects on net N mineralization in incubated soils. The greatest effect of trenching was to increase net N mineralization under favorable temperature and moisture conditions. Irrigation of field plots increased both CO2evolution and net N mineralization. Overall, these data are consistent with the hypothesis that plant roots reduced microbial activity by moisture uptake during the time of the study.