Agriculture Reference
In-Depth Information
Ecosystem-Level Characteristics
Annual production output
Components of the productivity process
Diversity: structural, functional, vertical, horizontal, temporal
Stability and resistance to change
Resilience and recovery from disturbance
Intensity and origins of external inputs
Sources of energy and efficiency of use
Nutrient cycling efficiency and rates
Population growth rates
Community complexity and interactions
TA B L E 2 1 . 3
Ecological Parameters Related to Agroecosystem
Sustainability
Characteristics of the Soil Resource
Over the long term
Soil depth, especially that of the topsoil and the organic horizon
Percent of organic matter content in the topsoil and its quality
Bulk density and other measures of compaction in the plow zone
Water infiltration and percolation rates
Salinity and mineral levels
Cation-exchange capacity and pH
Ratios of nutrient levels, particularly C:N
referred to the chapter in which each factor is discussed
for more detail on the importance of that factor and how
it might be measured.
Over the Short Term
Annual erosion rates
Efficiency of nutrient uptake
Availability and sources of essential nutrients
S OCIAL C ONDITIONS OF S USTAINABLE
F UNCTION
Hydrogeological Factors
Agriculture has been overly focused on the narrow eco-
nomic goals of raising yields and increasing the returns
on investments. When we use the criteria of sustainability,
it is clear that the quality of life for the people involved
in agriculture must also be taken into account, observed,
and monitored over time. Social health, like soil health,
is a composite picture of many factors, or parameters.
These parameters include physical health and emotional
well-being for individuals, and equity, participation, social
function, and democratic expression for the family and
community.
For each parameter, we can integrate agroecological
concepts and social theory grounded in rural sociology to
arrive at a general condition that reflects social health. For
individuals, we can measure such factors as educational
attainment, incidence of drug and alcohol use, and overall
physical health. For families and communities, we can
assess characteristics such as changes in the number of
farms in the area, average income per farm, number of
farm-related businesses, and level of participation in
farmer networks. As for ecological parameters, social
parameters have specific rates, levels, values and relations
that together indicate a condition of sustainability; how-
ever, due to the great differences in culture, history, rela-
tionships, and belief systems, these indicators are more
subjective and location-specific. Since the evaluator of
sustainability cannot put his or her values on the people
or communities being evaluated, participatory approaches
to measurement are important (Bacon, 2005).
Some important social and economic parameters
related to agroecosystem and regional food system sus-
tainability are listed in Table 21.4. This is not an
exhaustive list. The social framework for sustainability
is discussed in more detail in Chapter 23 and Chapter
24, and the reader is referred to the recommended
On-Farm Water Use Efficiency
Infiltration rates of irrigation water or precipitation
Soil moisture-holding capacity
Rates of erosional losses
Amount of waterlogging, especially in the root zone
Drainage effectiveness
Distribution of soil moisture in relation to plant needs
Surface Water Flow
Sedimentation of water courses and nearby wetlands
Agrochemical levels and transport
Surface erosion rates and gully formation
Effectiveness of conservation systems in reducing non-point-source
pollution
Ground Water Quality
Water movement downward into the soil profile
Leaching of nutrients, especially nitrates
Leaching of pesticides and other contaminants
Biotic Factors
In the Soil
Total microbial biomass in the soil
Rates of biomass turnover
Diversity of soil microorganisms
Nutrient cycling rates in relation to microbial activity
Amounts of nutrients or biomass stored in different agroecosystem pools
Balance of beneficial to pathogenic microorganisms
Rhizosphere structure and function
Above the Soil
Diversity and abundance of pest populations
Degree of resistance to pesticides
Diversity and abundance of natural enemies and beneficials
Niche diversity and overlap
Durability of control strategies
Diversity and abundance of native plants and animals
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