The effects of litter production and litter depth on soil microclimate in a central european deciduous forest

We examined the influence of litter quality and litter depth on soil microclimate in the detrital manipulation plots in the SikfAkA(0)t Detrital Input and Removal Treatments (DIRT) experiment in northeastern Hungary. We measured the soil temperatures from 06.01.2001 to 06.16.2008 and air temperature from 06.17.2004 to 06.16.2008. DIRT manipulations include two litter addition and three litter removal treatments, and one Control. There were significant differences detected among plots in winter and summer soil mean temperatures (p < 0.001) as well as in the number of frost-free days. The highest annual soil temperature variation was detected in litter removal treatments, while the lowest variation was in Double Litter plots with the thickest litter layer. The root exclusion treatments had significantly greater soil moisture contents than other treatments due to loss of transpiration. Plots wetter and lower in organic matter showed lower winter temperatures. Climate change influences soil temperature and moisture content not only directly, but also through the change of litter production. Litter thickness can reduce the effects of soil temperature extremes and moderate minimum and maximum temperature values. These differences in soil microclimate may have a highly significant, but unrecognized effect on soil carbon balance through effects on microbial processing of litter and soil carbon.