2011 Annual Report 1a.Objectives (from AD-416) Measure soil microbial activity and soil carbon fractions of pretreatment soils collected from the Long Term Biomass Experiment at Temple, TX. 1b.Approach (from AD-416) GSWRL will collect soils from 24 experimental plots. Soil samples consist of soils from 0-3, 3-6, 6-12, 12-24, and 24-36" depth increments from three pooled 1.5" diameter cores per plot. Coarse (>250 micrometer) and fine (250-53 micrometer) particulate organic matter will be assessed on these samples using established procedures. Active soil microbial biomass will be determined using a substrate-induced respiration technique, and long-term (1-year) laboratory incubations will be conducted on two subsamples from each plot. These 1-year incubations will be used to determine soil pool sizes and turnover using a two-pool model of soil organic matter decomposition. 3.Progress Report This agreement was initiated in January 2011. The cooperator is assessing soil C pools in soils collected at the beginning of the Long Term Biomass Experiment. These data will provide a crucial baseline against which to assess potential changes in soil C pools resulting from the experimental treatments. The agreement funds lab supplies and a student assistant, and to date all the soil samples have been fractionated and are currently being analyzed for C and N contents. Progress is monitored through regular emails and phone conversations.