Perdas de nitrato e potássio em solos arenoso e argiloso e no cultivo do feijoeiro sob lâminas crescentes de irrigação
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2016-02-25
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Universidade Federal de Goiás
Resumo
The growing global demand for food and a decrease in opening up new areas
for expansion due to pressure by environmental preservation, has intensified the process of
verticalization of agricultural production, resulting in the shift of extensive to intensive
standard. In the Brazilian Cerrado, traditionally with low soil fertility and well defined
hydrological cycle, it is observed that this of intensification process has characterized itself
by applying large amounts of fertilizer and irrigation. However, mismanagement of
irrigation and the doses and times of application of nutrients, especially these with high
mobility in soil, can cause losses per leaching, resulting in economic and environmental
damage. The objective of this thesis was to quantify the losses of nitrate (NO3-) and
potassium (K+), under different managements of irrigation, in sandy and clay soils in
greenhouse, and at field, the effects in bean crop irrigated by sprinkling in clay soil. The
first experiment was conducted in 2014, Urutaí, Goiás, Brazil. Indeformed soil columns
were arranged in a randomized complete blocks design with three replications. As nitrogen
source was used calcium nitrate with 15.5% of Total Nitrogen (N) and as source of K+ was
used potassium chloride with 58% of K2O. In fertilized columns were used four blades of
water, equivalent to 50, 100, 150 and 200% of the water layer obtained by the mass
difference of the columns of the treatments 100%. The irrigations were applied every three
days for a period of 81 days. The losses of NO3- and K+ in the columns were quantified.
Joint analysis of data was performed according to the time factor. The second experiment
was conducted in 2014 in Oxisol Red Dystrophic clayey, in Urutaí, Goiás, Brazil. Four
irrigation levels were applied, the equivalent to 50, 100, 150 and 200% of crop
evapotranspiration (ETc), estimated by the method of Class A tank. The plots were
arranged in a randomized complete block design with four replications, and seven
evaluations of soil solution throughout the experiment. As K+ source was used the
potassium chloride with 58% K2O and as N source was used calcium nitrate with 15.5% of
N. To collect soil solution, extractors of solution were installed at depths of 0.20, 0.40,
0.60, 0.80 and 1.00 m, and certain of the extracted solution, the concentrations of NO3- and
K+. In crop harvest were evaluated the production components and productivity of beans.
With the first experiment it is concluded that the movements of N-NO3- and K+ varied
depending on the soil and irrigation levels, being that, the higher the applied water blade,
the greater the amount of leached ions NO3- and K+. With the second experiment it is
concluded that the movements of NO3- and K+ in the soil profile varied between the
treatments, showing increased losses, below the roots, due to the application of greater
irrigation blade, and that the correct irrigation management in the bean (100% the ETc),
combined with appropriate doses and periods of nitrogen and potassium applications
provide the best yield of grains
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MENDES, W. C. Perdas de nitrato e potássio em solos arenoso e argiloso e no cultivo do feijoeiro sob lâminas crescentes de irrigação. 2016. 102 f. Tese (doutorado em Agronomia) - Universidade Federal de Goiás, Goiânia, 2016.