Agriculture Reference
In-Depth Information
Due to the recorded losses during and after the agrochemical applications,
various forms of management and technology are also being explored to mitigate
or even nullify these effects. An alternative to increase the efficiency of using
fertilizers is the application of sources which present a slower or controlled release
of nutrients.
Conceptually controlled- and slow-release fertilizers, also called “smart fertil-
izers,” are prepared to release their nutrient content in a gradual fashion and, if
possible, match its release with the nutritional requirements of a plant or to make its
availability much longer than that of a reference product, such as high soluble
fertilizers, which rapidly make their nutrients available (Hanafi et al. 2000 ; Trenkel
2010 ). There is no official distinction between the concept of controlled-release and
slow-release fertilizers. Shaviv ( 2001 ) reported the following distinction: the term
“controlled-release fertilizers” is acceptable when applied to fertilizers in which the
factors that dominate the rate, type, and duration of release are well known and
controllable, during the preparation thereof; “slow-release fertilizers” involve a
slower nutrient release than usual, but the rate, type, and release duration are not
well controlled. However, the distinction between the terms is not determinative
because these definitions are still open and modifiable.
The significant advantages of these systems are that they can eliminate the use of
parcels of fertilization of covering, reducing the labor, saving fuel, minimizing soil
compaction and root damage, and preventing physical damage to the crop from the
application process, as well as reducing environmental contamination (Shaviv
2001 ; Trenkel 2010 ). Figure 11.1 shows a comparison between a conventional
system and a controlled release for a particular active ingredient.
For example, Zhao et al. ( 2013 ) evaluated the effects of applying controlled-
release fertilizer on the production, ammonia volatilization, nitrogen use efficiency,
and photosynthetic rate in maize cultivation (hybrid cultivar Zhengdan 958). They
Fig. 11.1 Difference between the conventional model and controlled-release system, indicating
different times of application for a compound
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