Agriculture Reference
In-Depth Information
1.1. Soil environment
Soil is one of the most important natural resources and plays a key role in agriculture. Healthy
soil is essential for growth and evolution of healthy plants. In addition to the production
function, the soil has many other functions such as filtering, buffering, transformation and it
is the environment for organisms and also its socio-economic function is not negligible.
There are following positive changes within organic farming:
a.
soil organic matter (up to 30% higher organic carbon content),
b.
increased soil biological activity (by 30-100 %), biomass decomposition indicator,
c.
higher total edaphon biomass (by 50-80 %),
d.
higher saprophytic fungi abundance, higher root colonization by mycorrhiza,
e.
more efficient use of acceptable resources by soil microorganisms,
f.
improved physical and chemical soil properties, soil structure,
g.
improved hydroscopicity and erosion threat reduction
The soil organic matter research is mostly concentrated on the organic carbon content and its
changes during conversion to organic farming. Many studies have confirmed that areas under
organic cultivation have a higher organic carbon content as compared with areas under
conventional cultivation. However, in some researches, there was a higher decomposition of
organic matter such as within more intensive soil cultivation associated with mechanical weed
control. However, long-term experiments have confirmed the hypothesis that organic farming
methods better protected the soil organic matter. The research also points to a larger amount
of humic substances. An important factor in the soil organic matter protection is the minimum
soil cultivation. A properly designed crop structure, fertilizers, etc. are also important. A higher
supply of organic matter in the form of crop residues and organic fertilizers creates favourable
living conditions for soil fauna. The soil provides a habitat for a large number of various
organisms. The positive role of organisms consists mainly in organic matter decomposition
and inorganic substances transformation where nutrients are more accessible for plants and
where is also a synthesis of complex organic substances enriching humus reserves in the soil.
In organic farming, the key role for nitrogen plant nutrition is played by a symbiotic fixation
with papilionaceous plants. In the soil, there is also a nonsymbiotic fixation, e.g. by in-the-soil-
free-living heterotrophic aerobic bacteria. Rhizosphere is a zone where the main part of
nutrient cycle takes part due to the interaction between soil, roots and microorganisms
colonizing the plant root environment. In organically cultivated soils, [35] has observed by
40% more mycorrhiza than in soils within integrated farming.
Natural and active edaphon contributes to the protection of plant roots against parasite and
pathogen attack but also to degradation of toxic substances which enter the soil within the
chemical plant protection, environmental contamination from industry as well as metabolic
products of other organisms. The soil deterioration leads to a biodiversity reduction. Biological
degradation of soils is usually associated with their physical and chemical degradation.
