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Dryland Agroecosystem Component
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Introduction
Dryland farming has led to historically large emissions
of CO2 from stored soil carbon and high rates of soil
erosion and water-borne sediment. With the development and adoption
of reduced tillage systems over the past 20 years, significant strides
have been made in reducing soil erosion and water quality degradation.
However, the potential for dryland farms to sequester carbon by
returning soil organic matter levels to near native condition has
not been reached. These systems also rely on inputs of nitrogen
fertilizer made from fossil fuel. Several strategies are being explored
to improve specific aspects of the environmental performance of
these systems, but few attempts have been made to analyze and optimize
dryland systems for greenhouse gas mitigation, soil and water conservation,
energy efficiency, and economic performance.
Major shifts in agroecosystem management strategy
currently recognized as key goals for achieving greater sustainability
are: (1) a shift from high to low disturbance systems where tillage
is greatly reduced or eliminated resulting in increased rates of
carbon dioxide capture from the atmosphere, conservation of water
and improved environmental quality; (2) a shift from monoculture
dominance to greater cropping diversity and intensity that results
in greater soil C storage and decreased necessity for external supplies
of environmentally hazardous agrichemicals; (3) increased reliance
on internal farm resources (i.e. energy, water, nutrients) resulting
in greater resource use efficiency; and (4) a shift from whole field
to site-specific management in order to achieve greater resource
use efficiency by tailoring agricultural inputs to within-field
conditions (precision agriculture). Our overall research goal is
to redesign dryland agroecosystems to achieve greater greenhouse
gas mitigation, soil and water conservation, energy efficiency,
and economic performance.
Current nitrogen (N) management strategies result
in substantial movement of N beyond farm boundaries and degradation
of air, water and soil at watershed and global scales. Improving
nitrogen use efficiency (NUE) is targeted as a national conservation
goal (CAST, 2004), a goal shared by producers who also seek greater
efficiencies in N use to reduce farm costs. Precision N management
that tailors fertilizer inputs to site- and time-specific field
conditions has been proposed as a strategy to improve N fertilizer
use efficiency. Although many precision agricultural technologies
are currently available either nationally or internationally, a
major barrier to their adoption has been the integration of these
technologies into a grower-oriented monitoring, application and
evaluation system for optimizing the economic and environmental
performance of N use. Our overall goals are to increase the adoption
of precision N management by integrating recent technological innovations
(combine grain protein and yield sensors, GPS, GIS, guidance, and
VRT) with decision support systems, and to demonstrate the effectiveness
of precision N application. Specific objectives are to: (1) demonstrate
and evaluate a suite of precision agricultural technologies that
measure and predict site-specific variables required to make and
improve N management decisions; (2) evaluate and improve site- and
time-specific N management strategies on grower fields; (3) conduct
economic and environmental cost/benefit analyses to evaluate conservation
technologies and effectiveness of precision N management; (4) produce
grower-oriented site- and time-specific N management monitoring,
decision-aid and evaluation tools required to formulate N efficient
and environmentally sound conservation strategies; and (5) disseminate
outreach/extension materials and give presentations documenting
the impact of precision N management in conservation systems.
We will apply precision conservation strategies at the farm level
in order to demonstrate their utility for increasing N use efficiency.
This effort will be achieved over three-years by means of a diverse,
interdisciplinary team consisting of producers, extension, researcher
and agency collaborators. Project activities include field-scale
evaluations, economic and environmental analyses, and extension/outreach
efforts on dryland wheat farms in the Palouse region of Northern
Idaho and Eastern Washington. Unique aspects of the project are:
(1) promoting the concept of precision conservation where a suite
of spatial technologies are integrated into sound resource conservation
planning and application; (2) introducing and evaluating innovative
precision agricultural technologies including on-line near-infrared
(NIR) spectroscopy for measuring site-specific grain protein concentration
during harvest and computing N indices useful for precision N management;
and (3) delivery of grower-oriented decision-aid tools for precision
N management including information that can be incorporated into
NRCS technical standards for nutrient management.
Objectives
Research objectives for the dryland agroecosystem
component are to:
1. Design and establish field-scale experimental
and demonstration sites for novel agroecosystems that facilitate
long-term assessment of environmental and socioeconomic factors
that impact greenhouse gas emissions, environmental health, resource
efficiency, and agricultural sustainability.
2. Characterize and model fluxes of nitrogen,
carbon, water, and energy under current and “climate friendly
farming” systems in dryland situations.
3. Use field research, biophysical modeling and
socioeconomic assessments to identify practical and adoptable
systems that will improve performance and maximize mitigation
of global greenhouse gas emissions, resource use efficiency and
water quality protection.
4. Provide education and outreach through tours,
presentations, publications, and media.
Field research and monitoring begins in Spring
2004.
For more information on the irrigated component
contact Dave Huggins, USDA-ARS.
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Updated
May 10, 2005
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