Uso de nitrogênio no cultivo de arroz irrigado e seus efeitos no solo, na planta e na emissão de óxido nitroso
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Data
2011-02-15
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Universidade Federal de Goiás
Resumo
In wetland soils are countless electrochemical changes, among the most
influenced by anaerobic conditions is nitrogen. The rice crop also determine changes in the
process, either by the nutrient uptake or by changes in the rhizosphere. The nitrogen can
guarantee high yields of rice, however, due to the inadequate use of nitrogen can have
nitrous oxide, which is a greenhouse gas. In this context, the research aimed to determine
the effects of nitrogen fertilizer in flooded lowland soils in soil chemistry and soil solution
on the plants and the emission of nitrous oxide. The experiment was conducted in pots at
Embrapa Rice and Beans. The treatments consisted of two rice genotypes (BRS Tropical
and BRA 051130) and three nitrogen (0, 150 and 300 mg N kg-1 soil). The experimental
design was randomized blocks with split plots. The flooding of the vessels took place on
the fifteenth day after planting. The collection solution was given 1, 3, 7, 14, 28, 39, 59,
67, 102 days after flooding. The collection system consisted of a perforated plastic pipe
and secured in the vessel walls, being closed at the ends. The solution was suctioned
through a syringe and then analyzed on Ca, Mg, K, P, Fe, Mn, NO3
-, NH4
+, pH and Eh
(directly to the pots). After the experiment was made at the soil sampling vessel,
comprising all the other treatments being performed analysis of Ca, Mg, K, P and soil pH.
The yield components studied were: plant height, tiller number, panicle number per plant,
panicle length, spikelet sterility, dry weight of 1000 grains, shoot dry weight, root dry
mass, grain yield, root length, grain harvest index, the contribution of the shoot dry weight
total contribution of root dry weight total. The method of collection of nitrous oxide was a
closed chamber in PVC material. Collections were undertaken throughout the rice cycle
and N2O concentration was measured by reading in a gas chromatograph. The results were
subjected to analysis of variance, treatment means compared by Tukey test. The pH,
exchangeable Ca, Mg, K and P in soil increased after the implementation of the
experiment. The values of Eh in soil solution decreased with time of flooding and
consequently the pH increased. The concentration of Ca and Mg in soil solution increased
with time of flooding and the K, Mn, NO3
-, NH4
+ declined over the period. The rice
genotypes showed differences in dry weight of 1000 grains. The dry weight of shoots
showed responses to nitrogen fertilization, since the height of the trees showed responses
to genotypes and N levels The total emission of N2O showed differences in nitrogen use
and for the rice genotypes. We observed that the genotype BRA 051130 showed
significantly higher total emission in relation to the treatment without plants.
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CARVALHO, Glaucilene Duarte. Use of nitrogen in the cultivation of rice and its effects on soil,
lant and nitrous oxide emission. 2011. 96 f. Dissertação (Mestrado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2011.