Marginality Principle - Principles of Sustainable Soil Management in Agroecosystems - page 42

soils, with its redistribution severely limiting its ability to serve the functions of
which it is capable. When soil is no longer able to produce a particular crop or to
absorb moisture and support vegetation necessary for high ecosystem functioning, it
becomes marginal.
It is marginal in that it no longer has the ability to provide the socially desired ser-
vice-provisioning society or to facilitate ecosystem functions. This is not a new phe-
nomenon. “The archeological record shows that some ancient people abused their soils
and that their civilizations were disrupted by the ecological and environmental conse-
quences” (Olson 1994). Good stewardship of the soil is one factor in continuing prosper-
ity; overcutting forests, overplowing fields, and overgrazing of pastures and rangelands
have accelerated erosion, diminishing crop yields and capacities to maintain a reason-
able standard of living (Olson 1994). Loss of topsoil from mismatch of soil character-
istics, crop choice, and management techniques on highly erodible lands as well as
reduced biologically diverse soil-conserving rotations in favor of continuous corn or
a corn-soybean rotation have created a quiet crisis in the world economy (Brown and
Wolf 1984; Olson 1994). Unlike earthquakes or volcanic eruption, this crisis is largely
human-made and unfolds gradually (Brown and Wolf 1984).
It is the gradual nature of soil loss that reduces the sense of risk. People will
tolerate higher risks from activities they view as highly beneficial, and voluntari-
ness of exposure is a key mediator of risk acceptance (Slovic 2009). The relation-
ship between perceived risk, perceived benefit, and risk acceptance is influenced by
familiarity, sense of control, and level of knowledge (Slovic 2009). Thus, a farmer
sense of their soil's vulnerability and being at risk is likely to increase if they expect
that an uncontrollable, external force such as extreme precipitation will result in field
flooding and runoff accompanied by large quantities of soil loss. However, without
the fear of a catastrophic event, agricultural management of soil becomes an unex-
amined, controllable routine decision in support of a highly beneficial activity, crop
production, and earning a good livelihood. And it is exactly this sense of the ordi-
nary that, without purposeful management, puts it at potential risk of losing its value
and becoming marginal.
2.7.2 W illingneSS anD c aPacity to P rotect S oil r eSource
The suite of crops, structures, and management practices farmers select to achieve
crop productivity and profitability often have unintended but critical consequences
for soil resources. Farmer interpretations of the environmental outcomes and the
meanings they give to the impacts of their management decisions on soil conditions
and water quality can be barriers to addressing difficult and complex soil problems
or sources of innovation and solutions (Comito et al. 2012). Farmer management of
soil is a social process based on the social construction of the risks and vulnerabili-
ties of weather and under what conditions soil might become increasingly marginal.
The farmer's concern and sense of risk are central to their purposeful management
of agricultural lands and willingness to respond and adapt to changing long-term
weather patterns that make soil losses even more likely (Arbuckle et al. 2013).
Two routine decisions, tillage and management of the water balance, have critical
implications for maintaining, enhancing, or reducing soil quality. These decisions