The global nitrogen cycle has reached the stage where more nitrogen is fixed by human driven means than natural processes annually. Fifty percent of all industrial nitrogen applied throughout human history has been applied since 1982. While necessary for rice production these practices might have adverse affects on neighboring wetland ecosystems. Excess nitrogen fertilizers can increase the plant biomass in the wetland ecosystem. Some plant species respond more positively to high nitrogen content, resulting in a change in plant distribution in these altered areas.
Nitrogen demanding species, especially grasses begin to dominate.
Taking into consideration our time and equipment limitations, our group developed a process to test the presence of nitrates within the watershed that has rice production draining into a natural wetland. We will investigate how nitrate concentrations in agricultural run off from rice cultivation is mitigated by natural wetlands. Materials and Methods Our group began our investigation by interviewing the Palo Verde Station manager, Ullisses Chavarria Garcia, and studying a topographic map of the area to determine the flow of the watershed. We used this information to determine areas for our water sampling. Samples were taken as water flowed from rice irrigation canals, in rice fields, and through wetland areas.