We monitored greenhouse gas (GHG) emissions from nine vineyards in Lodi, California from April 2011 – December 2012. These commercial vineyards are replicates of three soil series (Redding, San Joaquin, and Tokay), representing a spectrum of soil texture. We hypothesized that soil characteristics would influence the magnitude of GHG fluxes from precipitation and management events in a Mediterranean climate. During each field visit – every other week from April to October and monthly from November to March – we measured carbon dioxide (CO2) and nitrous oxide (N2O) fluxes, soil nitrate (NO3-N) and ammonium (NH4-N), and gravimetric water content (GWC) from vine and inter-vine (alleys) rows. Monthly, we collected soil samples for dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Additionally, we simulated early spring tillage in March 2012 and first precipitation event of a wet season in September 2012. The first precipitation event in October 2011 resulted in higher N2O fluxes at San Joaquin (35.6 ± 10.7 g N2O-N ha-1, n = 30) and Redding (30.1 ± 10.0 g N2O-N ha-1, n = 30) than Tokay (8.5 ± 3.9 g N2O-N ha-1, n = 30). In mid-May and mid-October 2012, CO2 fluxes were higher at Tokay than San Joaquin or Redding due to seasonal floor management practices, such as cultivation and mowing of cover crops. Management practices effected differences between vine rows and alleys for soil inorganic pools, DOC, and DON from June to October 2012. Precipitation and tillage simulations depicted similar magnitudes of GHG fluxes as monitoring data. Results from this 20-month study suggested differences in N2O fluxes among soils were due to precipitation events, while CO2 fluxes were related to soil disturbance from management practices at the beginning and end of the dry season.
|Advisor:||Steenwerth, Kerri L.|
|Commitee:||Horwath, William R., O'Geen, Anthony T.|
|School:||University of California, Davis|
|Department:||Horticulture and Agronomy|
|School Location:||United States -- California|
|Source:||MAI 55/04M(E), Masters Abstracts International|
|Subjects:||Climate Change, Agriculture, Soil sciences|
|Keywords:||Carbon dioxide, Nitrous oxide, Sustainable management, Vineyard practices|
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