04270naa a2200361 a 450000100080000000500110000800800410001910000140006024501240007426000090019830000130020749000330022050001390025352030420039265000110343465000100344565000120345565000110346765300250347865300110350365300250351465300250353965300190356465300210358370000210360470000150362570000230364070000160366370000180367970000180369770000280371577301650374315555662001-10-22       2001    bl uuuu     u00u1 u    #d1 aKANNO, T.  aDevelopment of grassland management technology for sustainable agropastoral systems in the sub-tropical zone in Brazil.  c2001  ap.63-74.  a(JIRCAS Working Report, 19).  aEMBRAPA-CNPGC and JIRCAS joint International Workshop on Agropastoral System in South America, held in Campo Grande, MS, Brazil, 1999.  aThe purpose of this study is to develop sustainable agropastoral systems for soil improvement, as well as to develop grassland management technologies in the Cerrado region of Brazil. The study consists of three parts: 1) na evaluation of the eco-physiological characteristics of available forage crops, 2) development of grassland management technologies to enhance animal production in the Cerrados, and 3) integration of such technologies for sustainable agropastoral systems in the Cerrados. A glasshouse experiment was conducted to compare the growth responses of Brachiaria decumbens (BD), Brachiaria brizanta (BB), and Panicum maximum (PM) to different P supplies (0,25, and 50 Kg P/há), and N supplies (25, 150 and 300 Kg N/há). Corresponding  to increases in the P levels, dry matter production increased sharply, while na increase in N from 150 to 300 Kg N/há did not significantly improve the dry matter production. The total dry matter yield of BB was significantly higher than that of BD and PM. The external N requirements of the species was in the following order: PM maior BB maior BD. The root biomass in soil layers at depths of 0, 10, 10-20, and 20-40 cm was measured in the pastures of BD, BB and PM. The root biomass, when measured per square meter, was in the following order: BB maior BD maior PM, with the root biomass of BB being significantly higher than those of the other grasses. Thus, it was concluded that BB plays a larger role in supplying organic matter to the soil than do BD and PM. The affects of fertilizer application (P and K) and the intoduction of a legume (Stylotanthes guianensis) on forage production, forage quality, and soil properties were examined in the Brachiaria decumbens pastures. Fertilizer application improved the dry matter productivity and increased the P and K content in leaves. Legume introduction improved the dry matter production and increased the percentage of top biomass in the plant. Digestibility and the crude protein content of the leaves were also improved by legume introduction, especially in the rainy season. The forage productivity of Panicum maximum pastures established after a 4-year cultivation of summer soybeans (CS4-P4) and a 4-year rotation of summer soybeans and millet for winter grazing (CSW4-P4) was evaluated. In the PM pasture of CSW4-P4, much less biomass and dry matter was produced than in the PM pasture of CS4-P4, and the copper and nitrogen content in the top parts of the plants in the PM pasture of CSW4-P4 were significantly lower than that of the PM pasture of CS4-P4. It seemed that the shortage of copper and nitrogen restricted the photosynthesis and forage production of the PM pasture. These mineral-deficiency problems in the PM pasture need to be overcome to develop sustainable agropastoral systems. Because of a higher dry matter productivity, a larger root biomass, and lower external nitrogen requirement as shown in the present study, BB appears to be a primising option in establishing sustainable agropastoral systems.  aBrazil  aCampo  aCerrado  aManejo  aAgropastoral systems  aBrasil  aGrassland management  aSistema agropastoril  aSustainability  aSustentabilidade1 aMACEDO, M. C. M.1 aUOZUMI, S.1 aEUCLIDES, V. P. B.1 aBONO, J. A.1 aYOSHIMURA, Y.1 aCORREA, M. R.1 aSANTOS JUNIOR, J. D. G.  tIn: KANNO, T.; MACEDO, M.C.M., ed. JIRCAS / EMBRAPA gado de corte international joint workshop on agropastoral system in South America. [Tsukuba]: JIRCAS, 2001.