Akademik Veri Yönetim Sistemi
Diğer Ülkelerden Üniversiteler Tarafından Desteklenmiş Proje, 2008 - 2011
Abstract
Nearly a quarter of all
cropland in the US is under no-till (NT) - a management practice with
well-documented positive effects on soil C sequestration, and soil quality
maintenance. Although widespread adoption of no-tillage farming can help
mitigate the global warming effect, there is a paucity of field-based data
regarding the long-term impact of NT on greenhouse gas (GHG) fluxes.
Accumulation of crop residue on soil surface increased soil moisture and
availability of labile organic substrates could stimulate the emission of
carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4)
from NT systems. Conversely, long-term adoption of no-tillage could lead to the
evolution of a more active population of methanotrophs, increase soil
macroporosity and ultimately improve the CH4 sink strength of
croplands. Our primary hypothesis in this study is that the longer no-tillage is
continuously applied to soil, the greater becomes the soil’s ability and
potential to oxidize CH4. We also recognize that expression
of the CH4 oxidation potential of NT soils could be hindered by other
soil factors. Thus, there is a need to examine discrepancies between biological
potential and actual CH4 fluxes in NT soils. Based on these
considerations, the proposed research will address the following three
objectives:
(1) Assess the impact of long-term
no-tillage on GHG fluxes, and examine relationships between gas fluxes and
biophysical properties of NT soils.
(2)
Evaluate the link between soil drainage characteristics and the impact
of long-term no-till on GHG fluxes.
(3) Characterize the CH4
oxidation potential of NT soils, and identify factors limiting expression of
that potential.
Although CH4 is a major focus, the proposed research is a comprehensive assessment encompassing all three major
soil-derived GHG (CO2, N2O, and CH4) in order
to fully appraise the global warming mitigation potential (GWMP) of no-tillage
farming. We will monitor GHG fluxes (2 full years) at research stations and
farmers’ fields in similar soil types and under no-tillage for up to 46 years.
Detailed studies using the kinetic approach, stable C isotope, and selective
inhibition techniques will be conducted in order to characterize the community
of CH4-oxidizers in NT soils and assess the effect of no-tillage
duration and soil drainage characteristics on GHG dynamics. These experiments
will be conducted to determine the potential for no-tillage soils to oxidize CH4
and to provide guidance as to management options that can be used to achieve
this potential. Our goal is to provide a basis to enhance and project the
contribution of no-till farming to regional GHG inventory under various
scenarios of conservation tillage adoption in US agriculture. The proposed
research addresses several priorities of the Air Quality program and most
specifically priority #2 “increase adoption of best management practices to
reduce agricultural emissions”.