Contribui??o da fixa??o biol?gica de nitrog?nio na produ??o sustent?vel da cultura de cana-de-a??car

• Autor(a) principal: Xavier, Rog?rio Pontes
• Data de Publicação: 2006
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/tede/545
• topic: quantifica??o da FBN; balan?o de N; quantifying BNF; N balance; Agronomia

Despite sugarcanes Biological Nitrogen Fixation (BNF) research efforts which have been carrying on in Brazil, most of its varieties still need nitrogen fertilizer complement, and the cost of this supply trends to raise following the petroleum price. Thus, the scientific research has worked on finding alternatives to nitrogen fertilizer through varieties with higher potential to the BNF; crops practical handling that would be able to increase BNFs contribution; and also, through selection and inoculation of bacterias lineage efficient to BNF. Seeking some of these answers, three experiments were developed at Embrapa Agrobiologia in Seropedica-RJ heading to identify the most efficient sugarcanes varieties to BNF based on balance techniques of N-Total on the system soil/plant; 15N natural abundance; and 15N isotopic dilution. The experiment results allowed concluding that: 1) The N total balance of soil/plant system after 8 and 13 years of harvesting was positive to the most varieties studied, showing a significant entry of nitrogen from de atmosphere by BNF to the soil/plant system; 2) The varieties Krakatau, SP 70-1143, SP 79-2312 and SP 71- 6163 confirmed potential to BNF as observed on previous studies; 3) The varieties RB 72-454, RB 82-5336, RB 75-8540 and RB 83-5089 showed high potential to BNF. 4) The soil type and the crops cycle have great influence on the BFN contribution; 5) The BNF is an important source of N for the soil/plant system; got a glimpse of right handling possibility (systems of sugar cane harvesting with crop residue remaining on the soil surface) and with the utilization of efficient varieties to BNF may be possible to reduce or even eliminate crops nitrogen fertilizers.