Uso de nitrogênio no cultivo de arroz irrigado e seus efeitos no solo, na planta e na emissão de óxido nitroso / Use of nitrogen in the cultivation of rice and its effects on soil, lant and nitrous oxide emission

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

15/02/2011

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.

ASSUNTO(S)

rice production greenhouse gas química do solo produção de arroz gás de efeito estufa agronomia soil chemistry

ACESSO AO ARTIGO

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