Understanding Soil

Recently I learned from other students in SOIL366 during the fall term at OSU-Cascades. One student persented a review on how red alder (Alnus rubra), which is a nitrogen fixer, was having an impact on conifer stand. The effects of nitrogen from the red alder was influencing the soil microbial community. The study was done on the Oregon Coast. In the study they notice a difference in stands and soil composition. With the right conditions they notice a healthy ecosystem, increase in soil fertility, and thriving microbial biomass and activity. The red alder presenting nitrogen to the soil altered the physiological profile of the microbial community, even if the ecosystem was already high in Nitrogen. Thank you Sher’ri Jackson for explaining the article number 14, “Red Alder (Alnus rubra) Alter community-Level Soil Microbial Function in Conifer Forest of the Pacific northwest, USA”.



One student persented information about how global climate changing and a fire influence many understories by impacting legumes and the biological nitrogen fixation in forest ecosystems. Legumes have an interesting job in healthy ecosystems. The legumes interface between the soil, plant and microbial community by being a nitrogen fixer, but with climate change and an increase in fire severity was impacting the species composition. The understory composition and certain species play a large role in a healthy forest ecosystem by supplying Nitrogen that sometime can be limited . This also influences the carbon partition in the soil. Thank you Camara Beldell-Stiles for ecplaing the article number 5, “Impact of Global Climate Change and Fire on the Occurrence and Function of the Understorey Legumes in Forest Ecosystems

 

I was then told about a study done in California on how microbial communities were responding to changes in vegetation composition and climate change, but was not really understood. Studies were done in grassland and oak/grassland and compared on how the vegetation species were influencing the soil and the cycling of carbon. PLFA was performed on samples to research how the fatty acid was influencing the microbial biomass and exzyme activities, respiration rates, and the activity of microbial groups. They notice a difference between the grassland sample and the oak/grassland samples. The microbial communities were sensitive to the environmental change and there was change when the samples were transplanted to the open grasslands, but when samples form the grass land were transplanted to the oak/grassland reaction in the microbial community change and decreased. It showed how microbes react to the new environment conditions. Thanks you John Pittman for explaining article 15, “Response of Microbial Community Composition and Function to Soil Climate Change”.