Resposta do arroz de terras altas a diferentes doses de carvão vegetal: desenvolvimento da planta e deficiência hídrica / Resposta do arroz de terras altas a diferentes doses de carvão vegetal: desenvolvimento da planta e deficiência hídrica / Response of upland rice to different doses of charcoal, plant development and water deficit / Response of upland rice to different doses of charcoal, plant development and water deficit

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

14/02/2011

RESUMO

The average national rice yield was 11,3 million tones, with a harvested area of about 2,7 million hectares (IBGE 2010). Part of this comes from upland production systems in savannas that have high acidity, low fertility, with low phosphorus and potassium levels, low cation exchange capacity and high aluminum saturation. Upland rice in the Brazilian savannas (Cerrados) experiences multiple abiotic stresses and is characterized by high levels of uncertainty caused by rainfall variability. The increasing consumption of plant biomass to generate energy has produced products and by-products with high potential for agricultural use. Among these products is charcoal, that, due to its physical-chemical and molecular properties, have beneficial effects for the physical, chemical and biological soil characteristics. The objective of this work was to investigate the effect of charcoal on soil chemical properties and on the development of upland rice, and on the transpiration rate response of upland rice as an alternative to decrease the effect of drought on its growth and development. Two pot experiments were carried out using a random split-plot experimental design. The main treatments (plots) were water stress (WS) and no-water stress (NWS) and the sub treatments (subplots) were different biochar doses, 0% or control (T1), 6% (T2), 12% (T3) and 24% (T4) in growing medium (sand). The plastic pots were randomized within the sub plots with six replications. The total transpirable soil water (TTSW), the p factor, defined as the average fraction of TTSW that can be depleted from the root zone before reduction in transpiration occurs and the normalized transpiration rate (NTR) were determined. Charcoal significantly increased dry matter accumulation and leaf area of rice plants in both experiments and positively affected the chemical and physical soil properties such as water retention and nitrate availability to the plants. Biochar addition increased TTSW, p factor and reduced NTR. Consequently, biochar addition was able to change the moisture threshold (p factor) of the growing medium, up to a maximum concentration of 12%, hence delaying the point where transpiration declines and affects yield.

ASSUNTO(S)

oryza sativa carvão vegetal de eucalipto (eucalyptus sp.) biomassa seca retenção de água estresse abiótico , dry biomass leaf area mineral nitrogen abiotic stress water deficit área foliar nitrogênio mineral cultivar brsmg curinga deficiência hídrica agronomia oryza sativa eucalypt (eucalyptus sp.) charcoal soil water retention brsmg curinga

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