Microbial Activity In A Degraded Latosol Treated With Sewage Sludge [atividade Microbiana Em Um Latossolo Degradado Tratado Com Lodo De Esgoto]

The degraded soil shows, in general, poor biological activity, considering its physical characteristics, low fertility and organic matter, mainly due to removal or degradation of its superficial layer. The sewage sludge, due to its high content of easily decomposed organic matter can be an alternate source of organic residues and combined to its high content of the principal nutrients for the plants can be an important factor to promote biological activities in degraded soil. In order to study the actions of the sewage sludge in the recovery of a degraded Latosol, the carbon in the microbial biomass (C mic), the carbon released CO2 (C-CO2) and the relation between microbial and organic carbon (Cmic/Corg) were used as indicators of the effects. To do so, two doses (30 and 60 Mg ha-1) of sewer slime applied in topdressing and incorporated together with a mineral fertilizer treatment, using the eucalyptus as a test crop. A completely randomized design with 4 treatments and 4 repetitions was used. The sewage sludge promoted increase of liberated C-CO2 and the C mic, which constitute the adequate quality indicators for monitoring the soil recovery.112195198Alvarenga, M.I.N., Siqueira, O.S., da Vide, A.C., (1999) Teor de carbono, biomassa microbiana, agregação e micorriza em solos de cerrado com diferentes usos. Ciência Agrotécnica, 23 (3), pp. 617-625. , Lavras, vAnderson, T.H., Domsch, K.H., Ratios of microbial biomass carbon to total organic carbon in arable soils (1982) Soil biology & Biochemistry, 21, pp. 471-479Balota, E.L., Colozzi Filho, A., Andrade, D.S., Hungria, M., (1998) Biomassa microbiana e sua atividade em solos sob diferentes sistemas de preparo e sucessão de culturas. Revista Brasileira de Ciência do Solo, 22, pp. 641-649. , Viçosa, vCattelan, A.J., Vidor, C., (1992) Sistemas de culturas e a população microbiana do solo. Revista Brasileira de Ciência do Solo, 14 (2), pp. 125-132. , Campinas, vD'Andréa, A.F., Silva, M.L.N., Curi, N., Siqueira, J.O., Carneiro, M.A.C., (2002) Atributos biológicos indicadores da qualidade do solo em sistemas de manejo na região do cerrado no sul do estado de Goiás. Revista Brasileira de Ciência do Solo, 26, pp. 913-923. , Campinas, vDemattê, J.L.I., (1980) Levantamento detalhado dos solos do campus, pp. 11-31. , Piracicaba: ESALQ, pHabte, M., (1989) Impact of simulated erosive on the abundance and activity of indegenous versicular-arbuscular mycorrhizal endophytes in as oxissol. Biology and Fertility of Soils, 7, pp. 164-167. , Heildelberg, vJenkinson, D.S.Ladd, J.N. Microbial biomass in soil: measuremente and turnover. In: Paul, E.A.Ladd J.N (eds). Soil biochemistry. Marcel Deker, 1981. p.425-471Lima, V.C., Lima, J.M.J.C., Eduardo, B.J.F.P., Cerri, C.C., Conteúdo de carbono e biomassa microbiana em agroecossistemas: Comparação entre métodos de preparo do solo (1994) Revista do Setor de Ciências Agrárias, 1391 (N2), pp. 297-302Matsuoka, M., Mendes, I.C., Loureiro, M.F., Biomassa microbiana e a atividade enzimática em solos sob vegetação nativa e sistemas agrícolas anuais e perenes na região de Primavera do Leste, MT (2003) Revista Brasileira de Ciência do Solo, 27, pp. 425-433. , Viçosa, vMelo, E.F.R.Q. Alterações nas características químicas do solo de uma área degradada em recuperaçã o. In: Balensiefer, M.Araújo, A.J.Rossot, N.C. In: Simpósio Sul Americano. 1 e Simpósio Nacional Sobre Recuperação de Áreas Degradadas, 2, 1994, Curitiba. Anais... Curitiba: FUPEF, 1994. p.371-81Ros, C.O., Aita, C., Cerettan, C.A., Fries, M.R., (1991) Lodo de esgoto: Efeito imediato no milheto e residual na associação aveia-ervilhaca. Revista Brasileira de Ciência do Solo, 17, pp. 257-261. , Campinas, vSauerbeck, D.R.Helal, H.M.Nonnen, S.Allard, J.L. Photosynthate consumption and carbon turnover in the rhizosphere depending on plant species and growth conditions. In: Colóquio Regional Sobre Matéria Orgânica do Solo, 1, 1982, Piracicaba. Anais... São Paulo: CENA/Promocet, 1982. p.171-174Sparling, G.P., Ratio of microrbial biomass carbon to soil organic carbon as a sensitive inicator of changes in soil orgânic matter (1992) Australian Journal of Soil Research, 30, pp. 195-207Vance, E.D., Brookes, P.C., Jenkinson, D.S., An extraction method for measuring soil microbial biomass C (1987) Soil Biology & Biochemistry, 19, pp. 703-707Vargas, L.K.Scholles, D. Biomassa microbiana e produção de C-CO2 e N mineral em um Podzolico Vermelho-Escuro submetido a diferentes sistemas de manejo. Revista Brasileira de Ciência do Solo, Viçosa, v.24, p.35-42, 200

Development of mutants of Coniothyrium Minitans with improved efficiency for control of Sclerotinia Sclerotiorum

Coniothyrium minitans (CM) is hyperparasitic to Sclerotinia sclerotiorum (SS), a pathogen of many economically important crops. In this paper, we describe the isolation of improved mutants of CM, using a UV - irradiation regime, with altered chitinase production and tolerance to high concentration of iprodione, which are effective against SS. Three out of the 59 mutants obtained inhibited the mycelial growth of CM. Infectivity of sclerotia by the new mutants was assayed by the plant-tissue-based system using carrot segments. More than 80% of sclerotia were colonized by the mutants and the wild-type CM. The mutant strains retained ability to produce significant amounts of chitinase. The mutants differed from their wild-type strain in appearance, morphology and sporulation. In conclusion, the results presented here provide evidence that the new biotypes of C. minitans are effective in controlling S. sclerotiorum