Evaluation of nitrogen transfer from nodulate alfafa to associated grasses under field conditions.

• Autor(a) principal: Burity, Hélio A.
• Data de Publicação: 2014
• Outros Autores: Faris, Mohamaed A., Coulman, Bruce E., Ta, Trung C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/15518
• topic: Medicaga sativa; Rhizobium meliloti; Phleum pratense; Bromus inennis; 15N isotope dilution; Medicago sativa, Rhizobium meliloti, Phleum pratense, Bromus inermis, fixação de nitrogênio, diluição isotópica, 15N.

The contribution of N2 . fixation to the nitrogen nutrition of alfafa (Medicaga sativa L.) and transference of N to associated grasses timothy (Phleum pratense L.) and bromegrass (Bromus inennis Leyss.) when grown in mixture, were estimated using the 15N isotope dilution technique. The percentage of alfafa N derived from atmosphere (% Ndfa) increased throughout the growing seasons ranging from 63 to 83%. The total amount of N2 fixed by alfafa has shown a pattern similar to % Ndfa with slight increases to the absolute amount of N2 fixed by alfalfa in mixed stands. N transfer from alfafa to an associated grass was evident, and contributed 26, 46 and 38% of the total annual N yield of grass and represented an absolute amount of about 5.0, 20.0 and 19.0 kg. ha-1 during the first, second and third year. The results showed that all grass species benefitted from N transfer from alfafa, although the early maturity species with greater competitive ability are slightly more responsive.