Cultivo orgânico de milho em sistemas de plantio direto

• Ano de defesa: 2009
• Autor(a) principal: Corrêa, Maria Lita Padinha
• Orientador(a): Galvão, João Carlos Cardoso
• Banca de defesa: Rocha, Valterley Soares , Ferreira, Lino Roberto , Trivellato Barrantes, Maria Dalva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Zea mays; Canavalia ensiformis; Plantas daninhas; Microbiologia do solo
• Palavras-chave em Inglês: Zea mays; Canavalia ensiformis; Weeds; Soil microbiology
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1122

The objective of this study was to evaluate the no-till systems in organic maize cultivation through the soil microbiological indicators, agronomic performance of maize and weed dynamics. The experiment was conducted at the Experimental Station of Coimbra, located in the city of Coimbra, Minas Gerais State, belonging to the Federal University of Viçosa. The no-tillage system was adopted in the area between the years 2003 and 2006. In 2007 the area was plowed and separeted by a railing. In the years in succession (2008 and 2009) it was returned to the no-till system. The treatments consisted of no-till systems defined as: PDT1 (traditional tillage without fertilization + herbicide); PDT2 (traditional tillage with mineral fertilizer at a dose of 300 kg ha-1 of 8-28+16 + 100 kg ha-1 urea coverage + herbicides); PDT3 (traditional tillage fertilized with organic compound at a dose of 40 m³ ha-1 + herbicide); PDO1 (tillage fertilized with organic compound, at a dose of 40 m³ ha-1 + mowing); PDO2 (tillage 4 fertilized with organic compound, 40 m3 ha-1 + jack bean at a density of 3 plants per meter and mowing); PDO3 (tillllage 4 fertilized with organic compost, 40 m3 ha-1 + jack bean at a density of 6 plants per meter and mowing).The dynamics of weeds was represented by the relative importance and the similarity between the populations. In the agricultural years 2003/04 to 2008/09 the treatments evaluated were PDT1, PDT2, PDT3 and PDO1, and the agricultural years 2005/06 to 2008/09, containing PDT1, pdo1, PDO2 and PDO3 treatments. It was evaluated the agronomic performance of maize between the agricultural years 2006/07 to 2008/09, through orthogonal contrasts between the means of variables in different systems and data were analyzed using the F test at 5% probability. In the 2007/2008 agricultural year the assessment of microbiological indicators of soil was performed. The main results were as follows: Artemisia verlotorum and Cyperus rotundus showed the highest rates of relative importance; the plowing and harrowing after four years of tillage stimulated the emergence of the species Ipomoea grandifolia e Cynodon dactylon; the application of herbicides or mowing provided greater changes in the establishment of the weed community than the type of fertilizer used; the intercropping corn with six jack bean resulted in higher differences in the composition of the weed community in relation to other systems and provided reduction in the relative importance of the species Artemisia verlotorum, Bidens pilosa e Digitaria sp; the intermediate conventional tillage (plowing and harrowing) provided reductions in the relative importance index of the species Cyperus rotundus e Commelina benghalensis, however increased the relative importance of the species Ipomoea grandifolia in all treatments; the intercropping jack bean with maize on a density of six plants per meter provided an increase in grain yield; the intercropping corn and jack bean was effective among the organic systems to reduce the dry mass of weeds; the extension of the cycle of legume increased the dry matter in the system.In the assessment of microbial indicators of soil it was found that the soil C-microbial was not a good indicator of the quality, that the values of enzyme activities were higher in soils with organic management evincing them as indicators of functionality potential of the systems and that the higher microbial activity and higher rate of FDA (fluorescein diacetate hydrolysis) was the organic system, which was attributed to organic matter content in soil.