Abstract
It has been shown that with careful grazing management and addition of Pand K, but not N, fertilisers Brachiaria pastures are ableto maintain sustainable live weight gains over many years. However, standardon-farm practice, which generally involves high stocking rates, leads after afew years to pasture decline due mainly to N deficiency for grass regrowth. Togenerate an understanding of the mechanism of pasture decline and possiblemanagement options to mitigate this process, a study was performed in theAtlantic forest region of the south of Bahia state to study the N dynamics inpastures of Brachiaria humidicola subject to threedifferent stocking rates of beef cattle, with and without the presence of theforage legume Desmodium ovalifolium. Despite the fact thatthe C:N ratio of the deposited litter was high (60 to 70) the rate ofdecomposition was very rapid (k ∼ −0.07 gg−1 day−1) and annual rates of Nturnover through the litter pathway were between 105 and 170 kg Nha−1 year−1. In the grass-onlypasturesas stocking rate increased from 2 to 3 head ha−1, N recycledinthe litter decreased by 11%, but a further increase to 4 headha−1 decreased N recycling by 30% suggesting thatbeyonda certain critical level higher grazing stocking rates would lead to pasturedecline if there was no N addition. High stocking rates decreased theproportionof the legume in the sward, but at all rates the concentration of N in both thegreen and dead grass in the forage on offer and in the litter was higher in themixed sward. The presence of the legume caused a decrease in the C:N ratio ofthe microbial biomass while both soil N mineralisation and nitrificationincreased. This increased rate of turnover of the microbial biomass and thecontribution of N2 fixation to the legume resulted in largeincreasesin the N recycled via litter deposition ranging from 42 to 155 kg Nha−1 year−1.
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References
Alves B.J.R., Boddey R.M. and Urquiaga S. 1993a. A rapid and sensitive flow injection technique for the analysis of ammonium in soil extracts. Commun. Soil Sci. Plant Anal. 24: 277–284.
Alves B.J.R., Urquiaga S., Cadisch G., Souto C.M. and Boddey R.M. 1993b. In situ estimation of soil nitrogen mineralization. In: Mulonguy K. and Merckx R. (eds), Dynamics of Soil Organic Matter in Relation to Sustainability of Tropical Agriculture. Sayce Publishing, Exeter, UK, pp. 173–180.
Alves B.J.R., Rezende C.deP., Resende A.S., Macedo R., Tarré R.M., Urquiaga S. et al. 2000. Estimation of N2 fixation in Desmodium ovalifolium from the relative ureide abundance of stem solutes: Comparison with the 15N-dilution and an in situ soil core technique. Nutr. Cycl. Agroecosyst. 56: 177–193.
Amato M. and Ladd J.N. 1988. Assay for microbial biomass based on ninhydrin-reactive nitrogen in extracts of fumigated soils. Soil Biol. Biochem. 20: 107–114.
Ball R., Keeney D.R., Theobald P.W. and Nes P. 1979. Nitrogen balance in urine-affected areas of a New-Zealand pasture. Agron J. 71: 309–314.
Boddey R.M., Rezende C.deP., Pereira J.M., Cantarutti R.B., Alves B.J.R., Ferreira E. et al. 1995. The nitrogen cycle in pure grass and grass/legume pastures: Evaluation of pasture sustainability. In: Nuclear Techniques in Soil-Plant Studies for Sustainable Agriculture and Environmental Preservation. FAO/IAEA, Vienna, Austria, pp. 307–319.
Boddey R.M., Rao I.M. and Thomas R.J. 1996. Nutrient cycling and environmental impact of Brachiaria pastures. In: Miles J.W., Maass B.L. and Valle do C.B. (eds), Brachiaria: The Biology, Agronomy and Improvement. CIAT, Cali, Colombia Publication 259., pp. 72–86.
Boddey R.M., Alves B.J.R., Cantarutti R.B., Rezende C.deP., Pereira J.M., Tarré R.M. et al. 1999. Effect of the introduction of a forage legume (Desmodium ovalifolium) on nitrogen cycling in Brachiaria humidicola pastures in the extreme South of Bahia Proc Int Symp Pasture Ecophysiology and Grazing Ecology, 24–26 August, Curitiba, Paraná, Brazil. pp. 253–256.
Brookes P.C., Landman A., Pruden G. and Jenkinson D.S. 1985. Chloroform fumigation and the release of soil nitrogen: a rapid direct extraction method to measure microbial biomass nitrogen in soil. Soil Biol. Biochem. 17: 837–842.
Cadisch G. and Giller K.E. 1996. Estimating the contribution of legumes to soil organic matter build up in mixed communities of C3/C4 plants. Soil Biol. Biochem. 28: 823–825.
Cadisch G., Carvalho E.F., Suhet A.R., Vilela L., Soares W., Spain J.M. et al. 1994a. The importance of legume N2-fixation in sustainability of pastures in the cerrados of Brazil Proceedings of the International Grassland Congress, Palmerston North, New Zealand, 1993. pp. 1915–1918.
Cadisch G., Schunke R.M. and Giller K.E. 1994b. Nitrogen cycling in a pure grass pasture and a grass-legume mixture on a red Latosol in Brazil. Trop Grassl. 28: 43–52.
Cadisch G., Imhof H., Urquiaga S., Boddey R.M. and Giller K.E. 1996. Carbon turnover (δ13C) and nitrogen mineralization potential of particulate light soil organic matter after rainforest clearing. Soil Biol. Biochem. 28: 1555–1567.
Euclydes R.F. 1983. Manual de Utilizaçao do Programa SAEG (Sistema para Análises Estatísticas e Genética). Universidade Federal de Viçosa, Viçosa, MG, Brazil, p. 59.
Ferreira E., Tarré R.M., Macedo R., Rezende C.deP., Pereira J.M., Alves B.J.R. et al. 2001. Nitrogen loss from cattle dung under tropical conditions. (submitted).
Giné M.F., Bergamin Filho H., Zagatto E.A.G. and Reis B.F. 1980. Simultaneous determination of nitrate and nitrite by flow injection analysis. Anal. Chim. Acta 114: 191–197.
Haynes R.J. and Williams P.H. 1993. Nutrient cycling and soil fertility in the grazed pasture ecosystem. Adv. Agron. 49: 119–199.
Joergensen R.G. and Brookes P.C. 1990. Ninhydrin-reactive nitrogen measurements of microbial biomass in 0.5 M K2SO4 soil extracts. Soil Biol. Biochem. 22: 1023–1027.
Lascano C.E. and Euclides V.P.B. 1996. Nutritional quality and animal production ofBrachiaria pastures. In: Miles J.W., Maass B.L. and Valle do C.B. (eds), Brachiaria: The Biology, Agronomy and Improvement. CIAT, Cali, Colombia. Publication 259, pp. 106–123.
Lomnicki A., Bandola E. and Jankowska K. 1968. Modification of the Wiegert—Evans method for estimation of net primary production. Ecology 49: 147–149.
Longland A.C., Theodorou M.K., Sanderson R., Lister S.J., Powell C.J. and Morris P. 1995. Non-starch polysaccharide composition and in vitro fermentability of tropical forage legumes varying in phenolic content. Animal Feed Sci. Technol. 55: 161–177.
Macedo R., Tarré R.M., Alves B.J.R., Urquiaga S., Rezende C.deP., Pereira J.M. et al. 1999. Calibraçao da técnica do 13C para avaliaçao de gramínea e leguminosa na dieta de bovinos. Proc. Int. Symp. International Symposium Grasslands Ecophisiology and Grazing Ecology. 24–26 August, Curitiba, Paraná, Brazil., pp. 329–332.
Macedo R., Tarré R.M., Alves B.J.R., Urquiaga S., Rezende C.deP., Pereira J.M. et al. 2000. Efeito da presença da leguminosa Desmodium ovalifolium no consumo de pastagens de Brachiaria humidicola (Rendle) Schweickt por bovinos de corte. Proc. Congresso Latino-Americano del Producione Animal, Montevideo, 28–31 March. CD-ROM.
McDonagh J.F., Toomsan B., Limpinuntana V. and Giller K.E. 1995. Grain legumes and green manures as pre-rice crops in Northeast Thailand. 2. Residue decomposition. Plant Soil 177: 127–136.
Neill C., Piccolo M.C., Steudler P.A., Melillo J.M., Feigl B.J. and Cerri C.C. 1995. Nitrogen dynamics in soils of forests and active pastures in the western Brazilian Amazon basin. Soil Biol. Biochem. 27: 1167–1175.
Oliveira O.C., Oliveira I.P.de, Ferreira E., Alves B.J.R., Miranda C.H.B., Vilela L. et al. 2001. Response of degraded pastures in the Brazilian Cerrado to chemical fertilisation. In: Pasturas Tropicales. (in press).
Olson J.S. 1963. Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44: 322–331.
Pereira J.M., Nascimento D. Jr, Santana J.R., Cantarutti R.B. and Leao M.I. 1992. Teor de proteína bruta e digestibilidade “in vitro” da matéria seca da forragem disponível e da dieta selecionada por bovinos em pastagem de B. humidicola (Rendle) Schweickt, em monocultivo ou consorciado com leguminosas, submetida a diferentes taxas de lotaçao. Rev. Soc. Bras. Zootec. 21: 104–117.
Piccolo M.C., Neill C. and Cerri C.C. 1994. Comparison of methods for measuring soil nitrogen transformations along a tropical forest-to-pasture chronosequence. Plant Soil 162: 61–70.
Raison R.J., Connell M.J. and Khanna P.K. 1987. Methodology for studying fluxes of soil mineral-N in situ. Soil Biol. Biochem. 19: 521–530.
Rezende C.deP., Cantarutti R.B., Braga J.M., Gomide J.A., Pereira J.M., Ferreira E. et al. 1999. Litter deposition and disappearance in Brachiaria pastures in the Atlantic forest region of the South of Bahia, Brazil. Nutr. Cycl. Agroecosyst. 54: 99–112.
Robertson F.A., Myers R.J.K. and Saffigna P.G. 1993. Carbon and nitrogen mineralization in cultivated and grassland soils in subtropical Queensland. Aust. J. Soil Res. 31: 611–619.
Russelle M.P. 1997. Nutrient cycling in pasture. In: Gomide J.A. (ed.), Proc Int Symp Animal Production under Grazing. Viçosa, MG, Brazil, 4–6 Nov. pp. 235–266. Universidade Federal de Viçosa, MG, Brazil.
Svecar T.J. and Boutton T.W. 1985. The use of stable carbon isotope analysis in rooting studies. Oecol. 67: 205–208.
Sylvester-Bradley R., Mosquera D. and Mendex J.E. 1988. Inhibition of nitrate accumulation in tropical grassland soils. Effect of nitrogen fertilization and soil disturbance. J. Soil Sci. 39: 407–416.
Thomas R.J. 1992. The role of the legume in the nitrogen cycle of productive and sustainable pastures. Grass Forage Sci. 47: 133–142.
Thomas R.J. and Asakawa N.M. 1993. Decomposition of leaf litter from tropical forage grasses and legumes. Soil Biol. Biochem. 25: 1351–1361.
Thomas R.J., Fisher M.J., Ayarza M.A. and Sanz J.I. 1995. The role of forage grasses and legumes in maintaining the productivity of acid soils in Latin America. In: Lal R. and Stewart B.A. (eds), Soil Management — Experimental basis for sustainability and Environmental Quality. CRC Press, Boca Raton, Florida, USA, pp. 61–83.
Till A.R. 1981. Cycling of plant nutrients in pastures. In: Morley F.H.W. (ed.), Grazing Animals. Elsevier Scientific, Oxford, UK, pp. 33–53.
Urquiaga S., Cruz K.H.S. and Boddey R.M. 1992. Contribution of nitrogen fixation to sugar cane — Nitrogen-15 and nitrogen-balance estimates. Soil Sci. Soc. Am. J. 56: 105–114.
Urquiaga S., Cadisch G., Alves B.J.R., Giller K.E. and Boddey R.M. 1998. The influence of the decomposition of roots of tropical forage species on the availability of soil nitrogen. Soil Biol. Biochem. 30: 2099–2106.
Vallis I. and Gardener C.J. 1984. Short-term nitrogen balance in urine-treated areas of pasture on a yellow earth in the subhumid tropics of Queensland. Aust. J. Exp. Agric. Anim. Husb. 24: 522–528.
Vance E.D., Brookes P.C. and Jenkinson D.S. 1987. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem. 19: 703–707.
Vanlauwe B., Nwoke O.C., Sanginga N. and Merckx R. 1996. Impact of the residue quality on the C and N mineralization of leaf and root residues of three agroforestry species. Plant Soil 183: 221–231.
Wachendorf C., Irmler U. and Blume H.P. 1997. Relationship between litter fauna and chemical changes of litter during decomposition under different moisture conditions. In: Cadisch G. and Giller K.E. (eds), Driven by Nature: Plant Litter Quality and Decomposition. CAB International, Wallingord, UK, pp. 135–144.
Weider R.K. and Lang G.E. 1982. A critique of the analytical methods used in examining decomposition data obtained from litter bags. Ecology 63: 1636–1642.
Zimmer A.H. and Euclides-Filho K. 1997. Brazilian pasture and beef production. In: Gomide J.A. (ed.), Proc. Int. Symp. Animal Production under Grazing. Viçosa, MG, Brazil, 4–6 Nov. Universidade Federal de Viçosa, MG, Brazil, pp. 1–9.
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Cantarutti, R., Tarré, R., Macedo, R. et al. The effect of grazing intensity and the presence of a forage legume on nitrogen dynamics in Brachiaria pastures in the Atlantic forest region of the south of Bahia, Brazil. Nutrient Cycling in Agroecosystems 64, 257–271 (2002). https://doi.org/10.1023/A:1021415915804
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DOI: https://doi.org/10.1023/A:1021415915804