Population density and weed infestation in organic no-tillage corn cropping system under different soil covers

• Published in: Planta daninha 2014-12, Vol.32 (4), p.739-746
• Main Authors: Favarato, L.F., Galvão, J.C.C., Souza, J.L., Guarçoni, R.C., Souza, C.M., Cunha, D.N.
• Format: Article
• Language: English
• Subjects: Avena strigosa; Lupinus albus; organic farming; PLANT SCIENCES; straw
• ISSN: 0100-8358; 1806-9681; 0100-8358
• DOI: 10.1590/S0100-83582014000400008

Currently, one of the biggest challenges faced by organic no-tillage farming is weed control. Thus, the use of cropping practices that help in the control of weeds is extremely important. The objective of this study was to evaluate population density and level of weed infestation in an organic no-tillage corn cropping system under different soil covers. The experiment was conducted in a randomized block design with six repetitions and five treatments, consisting of three soil covers in an organic no-tillage system, and an organic and a conventional system, both without soil cover. The treatments with soil cover used a grass species represented by the black oat, a leguminous species represented by the white lupine, and intercropping between both species. Corn was sown with spacing of 1.0 m between rows and 0.20 m between plants, using the commercial hybrid AG 1051. Infestation in corn was evaluated at stages V5 and V10, and weed density was evaluated at stage V5. The use of black oat straw alone or intercropped with white lupine, in the organic no-tillage corn cropping system, reduced the percentage of weed infestation and absolute weed density. Management-intensive systems and systems without soil cover showed higher relative densities for species Oxalis spp., Galinsoga quadriradiata and Stachys arvensis. The species Cyperus rotundus showed the highest relative density on organic no-tillage corn cropping systems. Black oat straw in the organic no-tillage cropping system limited the productive potential of corn. Atualmente, um dos maiores entraves do sistema plantio direto orgânico é o controle de plantas daninhas. Desse modo, o uso de práticas culturais que auxiliem no controle dessas plantas torna-se de extrema relevância. Objetivou-se avaliar a densidade populacional e o nível de infestação de plantas daninhas no plantio direto orgânico de milho-verde sob diferentes coberturas de solo. O experimento foi conduzido no delineamento de blocos casualizados, com seis repetições e cinco tratamentos, constituídos por três coberturas de solo no sistema plantio direto orgânico e dois sistemas sem cobertura, sendo um orgânico e um convencional. Para os tratamentos com cobertura de solo foi utilizada uma espécie gramínea representada pela aveia-preta e uma espécie leguminosa representada pelo tremoço-branco, bem como o consórcio com as ambas espécies. A semeadura do milho para produção de espigas verdes foi feita no espaçamento de 1,0 m entre linhas e 0,20 m entre p