Introduction
Excessive application of fertilizer has caused the release of
nutrient elements, such as nitrogen and phosphorus, from agricultural
fields to aquatic systems. Leaching of nutrients from soils
may deplete soil fertility, accelerate soil acidification, increase fertilizer
costs for the farmers, reduce crop yields, and most importantly
impose a threat to environmental health (Bhargava and
Sheldarkar, 1993; Ozacar, 2003; Laird et al., 2010). High nutrient
levels in surface and/or groundwater can promote eutrophication,
excessive production of photosynthetic aquatic microorganisms
in freshwater and marine ecosystems (Karaca et al., 2004). It is
therefore very important to develop effective technologies to hold
nutrients in soils.