Agriculture Reference
In-Depth Information
budget of organic matter in the soil consisting in replacing mineralized organic matter by
inputs in the range of mineralization and losses.
Crop
Substance
corn
alfalfa
wheat
Water-soluble sugars
6.72
4.36
4.68
Hemicellulose and starch
42.61
14.85
23.30
Cellulose
23.29
32.25
42.12
Proteins
4.75
16.44
4.31
Lignin rest
18.27
29.60
23.00
Table 1.
Chemical composition of crop residues (% dry matter).
1.3. Water in landscape
Disposal of pesticides and morforegulators from the organic farming system reduces signifi‐
cantly the contamination of the environment including surface-and groundwater by residues
of these substances. In the area of organically cultivated fields, there are surface water and
groundwater less contaminated with plant protection products. These substances harm also
to aquatic animals, even at low concentrations (below detection limit) [33].
Also the prohibition of use of slightly soluble synthetic nitrogen fertilizers in organic agroe‐
cosystems reduces significantly the load of surface-and groundwater by nitrates. Reduced
animal surface load of soil (limit for organic farming 1.5 LU/ha, optimum 0.4-1.0 LU/ha in
relation to site conditions), optimal manure use (method of treatment and storage, time and
rate of its application, higher use of green manure and liquid manure restrictions), appropriate
use of leguminous plants and atmospheric nitrogen bounded by them, appropriate crop
rotation and an effort to maximize the vegetation cover (catch crops and permanent crops),
soil conservation cultivation methods and erosion reduction and other impacts contribute to
this. Within organic farming, there are by 35-64% less nitrates washed away as compared to
conventional farming agricultural plants [53]. In 40 scientific publication comparing nitrate
leaching or a leaching potential analysed by [22], twenty eight stated lower values within the
organic farming system, nine issued comparable data and only in three cases, the nitrate
leaching respectively its potential were higher within organic farming than in conventional
one. Yet, there were two critical areas for potential water pollution recognized and studied
within organic farming. These are manure composting and farming with residual nitrogen
from leguminous plants. Storage and composting of manure on unpaved surfaces can cause
leakage and subsequent contamination of groundwater and surface water. A significant
leaching can also occur when the nitrogen source accumulated by leguminous plants is
inappropriately used, i.e. by ploughing alfalfa in autumn, followed by sowing crops with low
demands on soil nitrogen content [48].
Nutrients from intensively cultivated cropland load water due to overland flow. Within
organic farming, this risk is reduced by greater ruggedness of landscape, more extensive
