ORIGINAL RESEARCH
Differences in the Accumulation
and Redistribution of Dry Matter and Nmin
Content in the Cultivation of two Different Maize
(Zea mays L.) Cultivars for Grain
Piotr Szulc
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Department of Agronomy, Poznań University of Life Sciences,
Mazowiecka 45/46, 60-623 Poznań, Poland
Pol. J. Environ. Stud. 2012;21(4):1039-1046
KEYWORDS
ABSTRACT
A field experiment was carried out in the Department of Agronomy of Poznań University of Life
Sciences on the fields of the Research and Education Unit in Swadzim in 2009-10. Two different genotypes
of maize cultivated for grain that exhibited different aging rates were compared: ES Palazzo and ES Paroli
“stay-green”-type cultivar. The dynamics of dry matter accumulation were assessed 10 times every 14 days.
We found that together with the progress of vegetation, the “stay-green” hybrid accumulated a significantly
greater amount of dry matter in comparison with the traditional cultivar. During the generative development,
the differences in production of dry matter of a single plant between the examined cultivar types were even
significantly greater. The absolute growth rate (AGR) of dry matter of a single plant, leaf blades, and grain
was higher for the “stay-green” hybrid when compared to the other examined cultivar. In order to assess the
amount of soil mineral nitrogen remaining after plant harvesting in the autumn, the Nmin method was used in
the present research. The soil mineral nitrogen content (N-NH4+N-NO3) after harvesting of ES Palazzo cultivar
was significantly higher in comparison with the ES Paroli “stay-green” cultivar. A higher content of both
mineral nitrogen forms after plant harvesting was observed in the 0-30 cm soil layer than in the 31-60 cm soil
layer, irrespective of the type of maize hybrid. The content of nitrate nitrogen N-NO3 in the total amount of
Nmin in the 0-30 cm soil layer amounted to 79.6%, while at a depth of 31-60 cm it amounted to 81.2%. The
examined cultivars affected the content of potassium and magnesium in soil after harvesting. However, no significant
influence of maize hybrid type on the content of phosphorus and soil pH was found. A significantly
lower amount of magnesium and potassium in soil after harvesting the “stay-green” cultivar when compared
to the traditional cultivar proves that the main source of accumulation of these macroelements in the stage of
generative growth are soil resources. This results from demand for these elements in the stage of maximum
increase in biomass of generative yield. Such behavior of “stay-green”-type plants should imply a fertilization
system with slow-acting fertilizers. Lack of magnesium and potassium in soil in the period of maturation of
“stay-green”-type maize may be a classical example of the law of the minimum.