19 The Effects of Plant Irrigation in Poland
383
the qualitative features that determine the suitability of the crop for consumption or
the processing technology of the raw materials obtained, are also of great importance.
An important aspect of irrigation efficiency is also an estimation of the amount of
by-product and mass of crop residue, the increase of which improves soil properties.
A direct production effect of plant irrigation, such as an increase in the main yield
and changes in its quality, is a consequence of modifications of plant growth and
development caused by this treatment. In particular, irrigation has a beneficial effect
on the activity of physiological processes, and the morphological and anatomical
structure of the plant, and consequently on the canopy structure, and finally on yield
components. According to the study by Karczmarczyk [13], irrigation combined
with an optimal rate of Nitrogen, Phosphorous, and Potash fertilizers resulted in a
significant increase in the intensity of physiological processes occurring in cereals
leaves, and thus higher assimilation of carbon dioxide, transpiration and stomatal
conductance. The intensification of physiological processes and the prolonged period
of the physiological activity of irrigated plants resulted in more robust growth, the
formation of taller and thicker stems with longer ears, as well as an increase in the
number and weight of grains per ear. Irrigation also contributed to the increase in plant
tillering and density of vegetation (the number of blades per unit area). In addition,
advantageous changes in yield composition, related to the increased plant density on
irrigated plots, higher abundance, and enlarged weight of a single component of the
yield, were found in other crops, for instance winter oilseed rape [14], potato [15]
and some vegetables [16, 17].
In order to determine the production effects of irrigated crops in Poland, numerous
scientific experiments were performed. Then, the results of particular experiments
were the subject of numerous syntheses. The most widely known synthesis works
are the study by Dzie˙ zyc [18] as well as the multiple-authors monograph edited
by Karczmarczyk and Nowak [19]. An analysis of yield modification through the
quantitative and qualitative aspects obtained under the influence of irrigation carried
out on this basis leads to the conclusion that the yield depends primarily on two
factors – rainfall conditions and soil properties.
19.2.1 Atmospheric Precipitation as the Factor Creating Yield
In Poland, in the zone of moderate transitory climate, irrigation treatment supplements the deficiencies of atmospheric precipitation, particularly during the period
of high water needs for plants. Therefore, the meteorological factor that has the
greatest impact on the production effects of irrigation is rainfall, especially total
rainfall and rainfall distribution in time. Since rainfall is characterized by very high
temporal variability in particular spans of the growing season, the effects of irrigation might be different in consecutive years. Despite this, the effects significantly
correlate with the amount of rainfall during the period of high demand for water of
individual species. This relationship, after regression equation transformation, can
be generalized according to the formula (1) by Grabarczyk [20]:
383
the qualitative features that determine the suitability of the crop for consumption or
the processing technology of the raw materials obtained, are also of great importance.
An important aspect of irrigation efficiency is also an estimation of the amount of
by-product and mass of crop residue, the increase of which improves soil properties.
A direct production effect of plant irrigation, such as an increase in the main yield
and changes in its quality, is a consequence of modifications of plant growth and
development caused by this treatment. In particular, irrigation has a beneficial effect
on the activity of physiological processes, and the morphological and anatomical
structure of the plant, and consequently on the canopy structure, and finally on yield
components. According to the study by Karczmarczyk [13], irrigation combined
with an optimal rate of Nitrogen, Phosphorous, and Potash fertilizers resulted in a
significant increase in the intensity of physiological processes occurring in cereals
leaves, and thus higher assimilation of carbon dioxide, transpiration and stomatal
conductance. The intensification of physiological processes and the prolonged period
of the physiological activity of irrigated plants resulted in more robust growth, the
formation of taller and thicker stems with longer ears, as well as an increase in the
number and weight of grains per ear. Irrigation also contributed to the increase in plant
tillering and density of vegetation (the number of blades per unit area). In addition,
advantageous changes in yield composition, related to the increased plant density on
irrigated plots, higher abundance, and enlarged weight of a single component of the
yield, were found in other crops, for instance winter oilseed rape [14], potato [15]
and some vegetables [16, 17].
In order to determine the production effects of irrigated crops in Poland, numerous
scientific experiments were performed. Then, the results of particular experiments
were the subject of numerous syntheses. The most widely known synthesis works
are the study by Dzie˙ zyc [18] as well as the multiple-authors monograph edited
by Karczmarczyk and Nowak [19]. An analysis of yield modification through the
quantitative and qualitative aspects obtained under the influence of irrigation carried
out on this basis leads to the conclusion that the yield depends primarily on two
factors – rainfall conditions and soil properties.
19.2.1 Atmospheric Precipitation as the Factor Creating Yield
In Poland, in the zone of moderate transitory climate, irrigation treatment supplements the deficiencies of atmospheric precipitation, particularly during the period
of high water needs for plants. Therefore, the meteorological factor that has the
greatest impact on the production effects of irrigation is rainfall, especially total
rainfall and rainfall distribution in time. Since rainfall is characterized by very high
temporal variability in particular spans of the growing season, the effects of irrigation might be different in consecutive years. Despite this, the effects significantly
correlate with the amount of rainfall during the period of high demand for water of
individual species. This relationship, after regression equation transformation, can
be generalized according to the formula (1) by Grabarczyk [20]: