 |
| Titel |
Effect of fertilization on N2O emissions from a marginal soil used for perennial grass bioenergy production |
| VerfasserIn |
Cathelijne Stoof, Imtiaz Karim, Cedric Mason, Dhanya Tadipatri, Ian Cary, Ryan Crawford, Julie Hansen, Jamie Crawford, Hilary Mayton, Tammo Steenhuis, Brian Richards |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094118
|
| Publikation (Nr.) |
 EGU/EGU2014-9512.pdf |
|
|
|
|
|
| Zusammenfassung |
| Marginal lands constitute the primary land base available for development of bioenergy
feedstocks in New York and the northeastern USA. Many of these soils are marginal because
seasonal wetness prevents profitable row crop cultivation, but they are potentially suitable for
perennial bioenergy feedstocks like switchgrass. Using these frequently wet soils for
bioenergy production has multiple environmental and socio-economic benefits, yet little is
known about how sustainable this practice is regarding greenhouse gas emissions –
particularly in relation to the application of fertilizers. In a 2.2-ha field study near Ithaca, NY,
USA, we are therefore monitoring greenhouse gas production from marginal silty clay loam
soils cultivated with switchgrass.
Here, we present results of our 2013 monitoring campaign, in which we assessed the
effect of surface-applied granular ammonium sulfate-fertilizer (0, 56 and 112 kg N/ha) on
N2O emissions along a natural catena from organic matter-rich wet lowland soil
to drier midslope and upslope soils with higher rock fragment content. Sampling
was done at 1 -2-week intervals around fertilization in June extending to 3-week
intervals around harvest in September, giving a total of 15 sampling events. Emissions
were sampled in a factorial design using four replicate static chambers per plot,
and soil moisture, soil temperature and perched water table depth was assessed
likewise.
As expected, N2O emissions increased with N-fertilizer application. This effect of
fertilization was much stronger than the effect of soil type or slope position. The
greatest N2O fluxes were observed a few days after fertilization; we will explore and
present the effects of rainfall, air temperature, soil moisture and soil temperature as
potential drivers of smaller peaks occurring post-fertilization. Since the non-fertilized
plots had negligible N2O emissions while still producing switchgrass at 6 Mg/ha,
unfertilized switchgrass production is naturally most sustainable if regarded solely
from an emissions standpoint. While biomass yields increased 1.5- to almost 2-fold
with addition of 56 and 112 kg-N/ha, the data suggest that the increase in N2O
emission was much greater, indicating that the N2O emission per unit yield may not
decrease but rather increase with increasing fertilizer application. This information is
valuable for quantifying environmental impact of bioenergy feedstock production from
the most important land base available in the regions with marginal agricultural
soils, and facilitates development of guidelines for sustainable farming practices. |
|
|
|
|
|
|