ANALYSIS OF PHOSPHORUS AND NITROGEN CONTENT IN PHILADELPHIA SOILS THROUGH UV-VIS SPECTROPHOTOMETRY

The concept of urban agriculture has grown in popularity over the past decade. With the focus of food production shifting to locally grown fresh produce, many city sites are turning green. But the success of an urban garden is dependent on the quality of the soil. Most importantly, the soil must contain sufficient nutrients to support plant growth. Phosphorus, present in soil in the form of phosphate, is a key nutrient necessary for cell division and tissue development. Nitrogen, in ammonium and nitrate, is a major component of chlorophyll and amino acids. Anthropogenic activities and processes have unique influences on urban soils which affect nutrient concentration and retention. Therefore, proper nutrient levels must be monitored and maintained in order for an urban garden to be successful. In this study, soils were analyzed from developed agricultural areas and vacant lots around Philadelphia, and compared to similar sites in other developed US cities. Nutrient concentrations including phosphate and ammonium were measured using UV-Vis spectrophotometry. Soil extracts from each site were prepared to represent the fraction of the compounds that would be readily accessible to plant roots. These results can be used to analyze the potential for urban agriculture development in southeastern Pennsylvania.