Aparecimento de plantas espontâneas com e sem perturbação do solo em condições mediterrânicas

Appearance of spontaneous plants from disturbed and undisturbed soil under mediterranean conditions

 

José Manuel Godinho Calado¹, Gottlieb Basch², Mário de Carvalho³

 

 

RESUMO

A diminuição da perturbação do solo é de extrema importância para a manutenção e preservação dos sistemas agrícolas. Por isso, o estudo realizado neste trabalho tinha como objectivo verificar o aparecimento das plantas espontâneas a partir do solo com e sem perturbação.

A população de plantas emergidas inicialmente, no Outono, foi controlada com perturbação do solo através da simulação da mobilização realizada pelo escarificador e sem perturbação do solo em que se aplicou um herbicida total e não residual. A experimentação foi efectuada em solos Mediterrâneos durante quatro anos, com um delineamento experimental em blocos casualizados e oito repetições.

De acordo com os resultados, verifica-se que a perturbação do solo efectuada para controlar a flora espontânea no Outono influencia significativamente o aparecimento das plantas em condições mediterrânicas e permite obter maior densidade populacional, que aumenta com o acréscimo da precipitação acumulada. Daqui conclui-se que em sistemas com diminuição da perturbação do solo, como por exemplo, de sementeira directa, é possível decrescer a infestação nas culturas de Outono-Inverno.

Palavras-chave: controlo da flora, densidade populacional, emergência, infestação de culturas.

 

 

ABSTRACT

The reduction of soil disturbance is extremely important for the conservation of soil and thus for the sustainability of agricultural systems. Soil disturbance interferes with a number of soil parameters including its fauna and flora. This paper deals with the comparison of the appearance of spontaneous plants from disturbed and undisturbed soil.

A study was conducted to compare the appearance of spontaneous flora in autumn after the simulation of soil tillage by a tine cultivator with the control of the already emerged plants through the application of a total herbicide and without any soil disturbance. The trials were realized on typical Mediterranean soils (Luvisol) over a period of four years in a completely randomized block design and with eight replications.

The results provide evidence that soil disturbance in autumn before crop establishment to control the spontaneous flora increases significantly the appearance of spontaneous plants under Mediterranean conditions and that this increase is even more pronounced in years with higher accumulated precipitation. This allows the conclusion that production systems based on low soil disturbance and especially no-till are able to decrease the population density of weeds in winter crops.

Keywords: weed control, population density, plant emergence, weed infestation

 

Texto completo disponível apenas em PDF.

Full text only available in PDF format.

 

 

REFERÊNCIAS BIBLIOGRÁFICAS

 

Botto, J.F.; Scopel, A.L.; Ballaré, C.L. & Sánchez, R.A. (1998) - The effect of light during and after soil cultivation with different tillage implements on seedling emergence. Weed Science 46: 351-357.         [ Links ]

Buhler, D.D.; Liebman, M. & Obrycki, J.J. (2000) -Review -Theoretical and practical challenges to an IPM approach to weed management. Weed Science 48: 274- -280.

Colbach, N.; Dessaint, F. & Forcella, F. (2000) -Evaluating field-scale sampling methods for the estimation of mean plant densities of weeds. Weed Research 40: 411-430.

Dyer, W.E. (1995) -Exploiting weed seed dormancy and germination requirements through agronomic practices. Weed Science 43: 498-503.

Grundy, A.C. & Mead A. (2000) -Modeling weed emergence as a function of meteorological records. Weed Science 48: 594-603.

Instituto Nacional de Meteorologia e Geofísica (1991) -O clima de Portugal -normais climatológicas da região de “Alentejo e Algarve” correspondentes a 1951/80 -fascículo XLIX. 4, Lisboa, 98 pp.

Johnson, E.N.; Kirkland, K.J. & Stevenson, F.C. (2002) -Timing of pre-seeding glyphosate application in direct-seeding systems. Canadian Journal of Plant Science 82: 611-615.

Locke, M.A.; Krishna, N.R. & Zablotowicz, R.M. (2002) - Weed management in conservation crop production systems. Weed Biology and Management 2: 123-132.

Lutman, P.J.W.; Cussans, G.W.; Wright, K.J.; Wilson, B.J.; Wright, G.McN. & Lawson, H.M. (2002) - The persistence of seeds of 16 weed species over six years in two arable fields. Weed Research 42: 231-241.

Marginet, A.; University of Manitoba; Van Acker, R.; Derksen, D.A.; Entz, M.H. & Andrews, T. (2000) - Wild oat (Avena fatua) emergence as affected by tillage and ecodistrit. In: Proceedings of the 2000 National Meeting - Expert Committe on Weeds, Alberta, Canada, pp.31-39.

Rahman, A.; James, T.K.; Mellsop, J. & Grbavac, N. (2000) -Effect of cultivation methods on weed seed distribution and seedling emergence. In: Proceedings of the 53^rd New Zealand Plant Protection Conference, pp.28-33.

Singh, S.; Kirkwood, R.C. & Marshall, G. (1999) -Biology and control of Phalaris minor Retz. (littlessd canarygrass) in wheat. Crop Protection 18: 1-16.

Shrestha, A.; Knezevic, S.Z.; Roy, R.C.; Ball-Coelho, B.R. & Swanton, C.J. (2002)-Effect of tillage, cover crop and crop rotation on the composition of weed flora in a sandy soil. Weed Research 42: 76-87.

Streit, B.; Rieger, S.B.; Stamp, P. & Richner, W. (2003) -Weed populations in winter wheat as affected by crop sequence, intensity of tillage and time of herbicide application in a cool and humid climate. Weed Research 43: 20-32.

Wicks, G.A.; Smika, D.E. & Hergert, G.W. (1988) - Long-term effects of no-tillage in a winter wheat (Triticum aestivum)-sorghum (Sorghum bicolor)-fallow rotation. Weed Science 36: 384-393.

Wicks, G.A.; Burnside, O.C. & Felton, W.L. (1995) -Mechanical weed management. In: Smith, A.E. (ED.). Handbook of Weed Management Systems. Marcel Dekker, Inc. pp.51-99.

 

^{1, 2, 3} Universidade de Évora, Departamento de Fitotecnia, Apartado 94, 7002-554 Évora. E-mail: ¹ jcalado@dfit.uevora.pt.

^{1, 2, 3} Instituto de Ciências Agrárias Mediterrânicas, Apartado 94, 7002-554 Évora.

Recepção/Reception: 2007.11.13 aceitação/acception: 2008.06.23