April 1, 2015
ABSTRACTS
Senior: Jarek Kwiecinski, AIMES at UNM
Improving the Carbon Use Efficiency of Soil Microbial Communities
Terrestrial soils contain 1800 gigatonnes (Gn of carbon, most of which is processed by soil microbial communities that emit 60 GT of carbon each year (Sinsabaugh, et a/., 2008; Jansson et al., 2010). Thus, it is important that methods to improve the efficiency of these microbes are considered. In this experiment, the amendments biochar, humate, and kenaf fiber were added to soil for evaluation of carbon use efficiency (CUE) improvements. Sites were selected at a location characteristic of a Pinon Juniper Woodland and amendments, as well as mixtures of amendments, were added to the soil. Respiration measurements were performed using an infrared gas analyzer. Biomass and extracellular enzyme activity (EEA) data have been collected by chloroform fumigation and fluorescence detections respectively. Soil C:N ratio and organic matter data have also been collected. CUE is calculated using its definition and stoichiometric models. According to ANOVA, sample type and date had significant effects on soil respiration, with dramatically increased respiration the result of monsoonal rainfall towards the end of the test period. Respiration was not reduced or increased by the addition of the amendments. According to a Tukey's HSD test result, all sample types showed significantly similar results overall. Kenaf samples saw higher CUE and EEA values, suggesting improving soil microbial productivity.
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Junior: Ronja Steinbach, Jefferson Middle School
Cut Off the Runoff (Reducing Agricultural Runoff)
This experiment was looking at simple groundcover options for agricultural lands that would reduce the amount of runoff. Originally it was thought that the straw would do the best because it retains water and is even used to reduce erosion. Mulch was supposed to do second best due to its absorbency, pea pebbles next best, as rocks are used to make the soil more porous, and the plain soil (the control) would do the worst Replicating an agricultural plot of land and using a simulation of a sprinkler, the amount of runoff that came off of each row was measured to the nearest milliliter. The results clear1y showed that the mulch did the best, with an average of 2,387ml per 30 seconds of watering. The straw came out next, with an average of3,324ml. The soil (control) came outat4,119ml and the pea pebbles had an average of 4,148ml, no significant difference from the control. This leads to the conclusion that if farmers use a mulch groundcover, they will reduce their runoff significantly, helping themselves as well as surrounding ecosystems.