Soil Physico-Chemical Properties, Herbaceous Species Diversity and Biomass in a Nitrogen Fertilization Experiment

Nitrogen (N) deposition in biosphere due to anthropogenic activities and its consequences on soil and vegetation is a global issue. In this study, we ask: (i) Do N fertilizations affect soil elements, species diversity, biomass and productivity in a herbaceous vegetation? And (ii) Does heterogeneity in soil property enhances the species diversity and biomass in N addition experiment? In this study, 15 sites, each having nine 1x1m plots, were established in this study in the campus of Banaras Hindu University, India. These plots were equally categorized in three groups The plots of group one were kept as control, the plots of group two were treated with 60 kg N ha(-1)yr(-1) and the plots of group three were treated with 120 kg N ha(-1)yr(-1). The plots were continuously treated with urea fertilizer from year 2007. In years 2009 and 2010, for each treatment level, soil physico-chemical properties, herbaceous diversity, biomass and productivity were estimated using standard methods. The data were subjected to proper statistical analyses. Study indicated that continuous N treatment lowered the soil pH and increased the biomass and productivity. Moderate N dose (60 kg N ha(-1) yr(-1)) experienced maximum diversity and heterogeneity in soil property. Further, results also suggested that under the condition of N treatments over several years, the spatial heterogeneity in soil property may support the herbaceous diversity and biomass for proper functioning of the ecosystems.