Agriculture Reference
In-Depth Information
gotten involved in soil and land stewardship.* Thus, within a given region, a par-
ticular religion can provide cultural cues, respond to cultural trends, and establish
links between religious and cultural perspectives that provide the basic frame of
orientation for those who work the soil. Soil stewardship can be greatly empowered
by such links. And yet, religious intentions and sensibilities are usually not sufficient
in themselves.
12.4 RELIGIOUS-CULTURAL PERSPECTIVE
IN NEED OF SOIL SCIENCE
As we have seen, religious traditions can influence individuals, communities, and
polities either through shared values or principled devotion, or through direct man-
agement. At these various levels, religious traditions and writings contribute to soil
stewardship in at least two ways. In general, they foster an appreciation for soil as a
gift to humans and as an essential resource for food production that sustains life (see
Hinduism,
Table 12.1
); in some cases, they also provide more specific management
instructions (Sikhism, Table 12.1; soil nutrients,
Table 12.2
). But the intention to be
a good steward of the soil does not automatically lead to best management prac-
tices. Sound stewardship can be religiously motivated, but scientific understanding is
often needed to make the stewardship effective. Consider the examples of irrigation
and of nutrient management.
12.4.1 i
irrigation
and
s
alinization
of
s
oil
Most irrigation water contains salts that accumulate in the irrigated soil as water is
removed by direct evaporation and transpiration through the crops. Sustainable irri-
gation requires (1) flushing salts from the soil by the application of water in excess
of crop needs and (2) soil drainage so that the salty flush water can be carried away
without waterlogging the soil. In addition, there must be some place for the drainage
water to go. Along streams and rivers, downstream water quality will deteriorate as
salt concentrations increase. In a geological basin, some land will be sacrificed in
low-lying ponds sterilized by the salt (Hillel 2008a; Szabolcs 1986).
For the most part, prescientific peoples have not understood this, and as a con-
sequence, their irrigation projects often failed over time because of salinization of
the soil. The classic case is in the Tigris-Euphrates valley of Mesopotamia (Hillel
2008b). The cultures of Sumer (ca. 4000 to 2500 BCE), Akkad (ca. 2500 to 2100
BCE), and Babylonia (ca. 2100 to 500 BCE) were each established further up the
valley than their predecessors because the lower delta lands became too salty for
crop production. Even the relatively salt-tolerant barley (compared to wheat) eventu-
ally failed because of too much salt in the soil (Artzy and Hillel 1988; Hillel 2008b),
and the salinized soils remain a problem into modern times (Richardson et al. 2005).
Another example is found on the soils of the American Southwest originally irri-
gated by the First Americans. Modern soil scientists have uncovered evidence of
salinization in those soils (Olson 1981; Palacios-Fest 1994), indicating that natural
*
See Section 12.5.4 below for more information about some of these programs.
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