Agriculture Reference
In-Depth Information
can be replaced with biological nitrogen in order to obtain healthy and environmentaly-
safe products.
Keywords:
Biofertilizer, chemical fertilizer, microorganisms, strawberry
I
NTRODUCTION
Plant nutrients are essential for the production of crops and healthy food for the world's
expanding population (Chen, 2006). The world population is expected to reach over 10 billion
in the year 2050 while agricultural production is growing at a slower rate of about 1.8%
annually (Sheikh, 2009). According to generally accepted calculations, between now and
2050, the world-wide demand for food will increase by 70%. With the conventional methods
of agriculture, agricultural production will not be able to grow fast enough to meet the needs
of the rapidly growing population. In order to overcome this problem, there is a pressing need
to intensify agricultural production in an ecologically responsible manner. Therefore, the
agricultural production must be focused on satisfying basic criteria of the sustainable
production concept where the fertilization strategy, among other practices, plays an important
role.
Worldwide experience in agricultural development has provided much evidence that
fertilizer application is the most efficient measure for the sustainable and increasing crop
production (Wang et al., 2013). However, research in this area is mostly focused on
increasing crop yields, whereas their cumulative effects (changes in soil biological and
chemical properties) are often neglected (Mandić et al., 2012). Numerous studies have shown
that increasing utilization of synthetic nitrogen fertilizers significantly contributes to a series
of undesirable effects and results in excessive environmental pollution. In particular,
investigations indicate that nitrogenous fertilizers used in agriculture contaminate surface and
underground waters (Beman et al., 2005), enhance N
2
O emissions into the atmosphere
(Galloway et al., 2003) and result in possible nitrate accumulation in plants. Accordingly,
attention has been focused on the use of different organic materials (e.g., animal manures,
crop residues, green manures, etc.) and biofertilizers (microbial inoculants) as an alternative
and/or a supplement to costly mineral fertilizers (Alfonso et al., 2005; Rolli, 2007; Mandic et
al., 2011; Pešaković et al., 2011; Pešaković et al., 2012; Djukic et. al., 2012a,b; Pešaković et
al., 2013). The main scope of these methods is to provide greater efficiencies, increase the
quality of agricultural products, reduce costs and
improve
the
quality
of life for growing
world population (Carvajal-Muñoz and Carmona-Garcia, 2012). Numerous studies (Higa and
Parr, 1994; Reddy, 2005; Tognetti et al., 2005) showed that rational use of microbial
inoculants, can provide certain physical (improving structure and aggregation of soil particles,
reducing compaction, and increasing the pore spaces and water infiltration), chemical
(improving nutrients availability in the soil, leaving free elements to facilitate their absorption
by the root system), and microbiological properties (suppression or control through
competition of pathogenic populations of microorganisms present in the soil and increasing
microbial biodiversity creating suitable conditions for the development of beneficial
microorganisms) of soil. Saharan and Nehra (2011), also reported that utilization of Plant
Growth Promoting Rhizobacteria (PGPR) as microbial inoculants can contribute to plant
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