Rate of Atmospheric Nitrogen Fixation in Temporary Pastures
Keywords:
amount of fixed nitrogen remained in soil, mean fixation rate, nitrogen fixation, pasture of Medicago sativa + Dactylis glomerataAbstract
This work presents the influence exerted by the bacterial inoculation of legumes and nitrogen-based fertilization of temporary pastures on the rate of atmospheric nitrogen fixation (BFN). The researches were carried out in an experimental display consisted of a bifactorial experience (A = bacterial inoculation; B = nitrogen doses), during a three-year period, by planting an association of Dactylis glomerata (60%) + Medicago sativa (40%). The estimated amount of BFN was determined with the method of nitrogen balance with a reference crop. The results achieved showed that, by inoculating the legume within the temporary pasture association, we may obtain an increase of the BFN rate from 2.66 kg/1% alfalfa to 3.24 kg/1% alfalfa, respectively an estimated amount of 0.65 kg Nfixed/day/ha, in the inoculated variant.
References
Boller B C and Nosberger J - Symbiotically fixed nitrogen from field-grown white and red clover mixed with ryegrasses at low levels of 15N-fertilization. Plant and Soil 104, 1987, 219-226.
Giller K. E.– Nitrogen fixation in tropical cropping systems. CABI Publishing, 2001, Wallingford, UK
Kristensen E. S. et al.– A simple model for estimation of atmospherically – derived nitrogen in grass – clover systems. Biological Agriculture and Horticulture, 12, 1995, 263-276
Ledgard, S. F. – Transfer of fixed nitrogen from white clover to associated grasses in swards grazed by dairy cows, estimated using 15N methods. Plant Soil 131, 1991, pp. 215-223.
Cuttle S. et al.– A review of leguminous fertility – building crops, with particular refence to nitrogen fixation and utilisation. Project OF0316, Institute of Grassland and Environmentl Research, Plas Goferddan, Aberystwyth SY 23 – 3 EB, 2003.
Moga I., Schitea Maria, Mateiaş M., - Plante furajere, Ed. Ceres, 1996, Bucureşti.
Vinther F. P. et al. – Estimating legume N2 fixation in a grass – clover mixtures of grazed organic cropping systems using two 15N methods. Agriculture, Ecosystems & Environment, 78, 2000,139-147
Peoples, M. B., Bowman, A. M., Gault, R. R., Herridge, D. F., Mc Callum, M. H., Mccormick, K. M., Norton, R. M., Rochester, I. J., Scammell, G. J. & Schwenke, G. D.– Factors regulating the the contributions of fixed nitrogen by pasture and crop legumes to different farming systems of eastern Australia. Plant and Soil, 228, 2001, pp 29-41
Burity H A, Ta T C, Faris M A and Coulman B E– Estimation of nitrogen fixation and transfer from alfalfa to associated grasses in mixed swards under field conditions. Plant and Soil 114, 1989, 249-255.
Ta, T. C., and M. A Faris– Effects of alfalfa proportions and clipping frequencies on timothy-alfalfa mixtures: II. Nitrogen fixation and transfer. Agron. J. 79:820-824, 1987.
