Spatiotemporal Dynamics of Soil Biogeochemical Characteristics Under Nitrogen Fertilization in Bioenergy Croplands
Soil biogeochemical properties such as moisture, pH, dissolved organic carbon and nitrogen (DOC, DON), and extracellular enzyme activities are important soil health indices. Yet their spatiotemporal patterns have been rarely examined in bioenergy croplands such as switchgrass (SG) and gamagrass (GG). Nitrogen (N) fertilization affects these variables’ dynamics and consequently influences soil carbon (C) and N sequestration. This study was to investigate effects of N fertilization and bioenergy crop type on spatiotemporal dynamics of these characteristics and evaluate whether soil glycosidases mediated soil C and N sequestration under N fertilization. A spatially explicit design and sampling strategy (288 samples at 0-10cm) were employed in a fertilization experiment with zero, low and high N input (NN, LN and HN: 0, 84, and 168 kg N ha−1 yr-1 urea, respectively) in SG and GG croplands. The forementioned soil biogeochemical properties and N, P-acquisition glycosidase activities were quantified. Formerly published data of C-acquisition glycosidases, soil organic carbon (SOC) and total nitrogen (TN) were also integrated. Results showed that LN significantly increased DOC while HN significantly increased BX, LAP, SOC and TN in SG. Significant positive correlations of LAP and SOC, TN were also discovered in SG. Spatial heterogeneity of biogeochemical properties and glycosidase activities were generally elevated by nitrogen fertilization, with GG generally higher than SG. Collectively, this study informed generally low sensitivity of soil biogeochemical features to fertilizer amendments in bioenergy croplands, yet it also suggested that glycosidase LAP facilitated soil C and N sequestration under intensive N fertilization in SG soil.
Environmental science|Biogeochemistry|Soil sciences
"Spatiotemporal Dynamics of Soil Biogeochemical Characteristics Under Nitrogen Fertilization in Bioenergy Croplands"
ETD Collection for Tennessee State University.