For example, in wine grapes where little fertilizer generally isused,
it may be difficult to further decrease emissions of N2O.Use of organic fertilizers and cover crops
instead of synthetic fertilizers tosupply necessary nitrogen may limit emissions but has not been proven.
Timing nitrogen applications to ensure maximum uptake by roots may decrease N2O emissions and nitrogen
leaching,but more research is needed.
Vineyard water use can impact GHG emissions and carbon
sequestration. The energy used during irrigation to pump
water results in GHG emissions. Moreover, a correlation
exists between increased irrigation and GHG emissions
from soil. At high moisture content, soils have minimal
oxygen content and microbes produce more N2O.
Anaerobic soils are optimal environments
for microbial production of N2O(and CH4,though less
important for vineyards). Wet soils, especially when warm,
can also increase CO2 emissions through increased microbial
activity and decomposition of organic matter.
In contrast, increasing irrigation can offset some GHG
emissions by stimulating vines to grow and store carbon
in permanent structures.
This is a form of above ground carbon sequestration
that is especially effective if vines live for
many years and much of the removed vine biomass is
incorporated into the soil to increase organic matter.
Various irrigation systems and patterns
may differently impact GHG emissions from soils. Drip irrigation is thought to produce less N2O than
flood or furrow irrigation at the vineyard level but more research is needed.
The act of tilling soil consumes substantial
quantities of fossil fuel.
Estimates of fuel usage during tillage
operations and potential savings from
alternative management strategies can
be determined using a general calculator
(Use the estimated acreage of a wheat
cover crop.) The Wine Industry GHG
also performs this function.
By breaking up soil aggregates,
tillage increases soil emissions of CO2
and possibly N2
O by mobilizing carbon
and nitrogen, thus allowing
microbes to access and consume previously
protected organic matter. Each