Environmental Engineering Reference
In-Depth Information
of output. Environmentally beneicial practices are being utilized more by farmers, such
as conservation tillage, improved manure storage, soil nutrient testing, and drip irrigation.
6.7 Concluding Remarks
The geoenvironment associated with agriculture plays a very important role in such
activities and events as carbon and nutrient cycling, climate change, maintaining eco-
system biodiversity and water-groundwater quality, and pollution management. As has
been stressed previously, the discussion concerning the impacts from agricultural prac-
tices in production of food are motivated primarily in respect to concerns for protection
of the geoenvironment. Accordingly, the impacts and the means to mitigate impacts are
all viewed from a geoenvironmental perspective. Many of these impacts and the means
to alleviate and eliminate them are well known to the agricultural/farming community
and that they share the same concern as those involved with geoenvironmental manage-
ment. There is validity to the thesis that many of the measures for mitigating, minimizing,
and even eliminating impacts from contaminant loading and soil quality impairment run
counter to intensive agricultural practices. Conlicts between agricultural productivity and
protection of the geoenvironment have always existed. However, if sustainability and/or
preservation of the quality of the geoenvironment are goals that have merit, it is necessary
to seek sustainable practices for both agricultural production and the geoenvironment.
Although soils have been exploited for agricultural and livestock purposes, they are
very vulnerable to environmental stresses and are renewable at very slow rates (over cen-
turies). They are at the interface of the lithosphere, hydrosphere, atmosphere, and bio-
sphere. Aquifers are subjected to overpumping, subsidence, and contamination. Excessive
extraction leads to subsidence, erosion, aridiication, and salination. Contamination from
farm wastes and other activities reduces the use of the water and can cause health prob-
lems. Lack of water will have a signiicant impact on agriculture. Conservation of water,
energy, and soil resources are required, and new technologies for agricultural practices
such as irrigation are needed. Recycling of crop residues and other wastes is another area
where considerable development is required.
Agricultural reshaping of the land leads to erosion and other soil displacements. It
changes the landscape and causes disruptions to the ecosystems and the environment
overall. More than 99% of the world's food comes from the land ecosystems and more than
70% of the freshwater is used for agriculture. Lack of available and good quality water
and soil limit food production today and will be even more strained as the population
increases.
Many contaminants are discharged by diffused means from farming activities and are
dificult to control. Water runoff and iniltration transports the contaminants to ground-
water, lakes, rivers, and marine areas. The sediments are subsequently responsible for
trapping many of these contaminants. Further investigations are required to better under-
stand the retention of the contaminants by plants and soil and the chemical and micro-
bial reactions governing the fate of the contaminants. Long-term monitoring is needed to
develop databases for predictive modeling and to evaluate the sustainability of the various
agricultural practices. An integrated approach of mitigation methods and reduction of the
contaminants at the source are required to reduce the impact on the surface and ground-
water. Multidisciplinary efforts and those involving the public are required to increase
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