Cover crop residue management for optimizing weed control

Abstract

Although residue management seems a key factor in residue-mediated weed suppression, very few studies have systematically compared the influence of different residue management strategies on the establishment of crop and weed species. We evaluated the effect of several methods of pre-treatment and placement of winter rye (Secale cereale L.) and winter oilseed rape (Brassica napus L.) residue on seedling emergence under field conditions. For both species two cultivars, differing in allelochemical content, were used. Residues incorporated in the upper soil layer exerted a large inhibitory effect on the establishment of the relatively early emerging lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.) seedlings, whereas the inhibitory effect on the slightly later emerging Stellaria media L. seedlings was variable, and often a stimulatory effect on the very late emerging Chenopodium album L. seedlings was observed. Differences between cover crop cultivars were minor. For winter oilseed rape residue, pre-treatment strongly affected the time-course of residue-mediated effects. Finely ground residues were only inhibitory to seedling establishment during the first two to three weeks, whereas cut residues became inhibitory after this period. For winter rye, residue placement was most important. Residue incorporation gave variable results, whereas placement of winter rye residue on top of the soil inhibited the emergence of all receptor species. In conclusion, the optimal residue management strategy for weed suppression depends both on the cover crop species used and the target weed species.

Effect of cowpea (Vigna unguiculata) intercropping on weed biomass and maize (Zea mays) yield

“…Because of these potential problems and increased public pressure on conventional agriculture, there is increasing interest in organic farming systems across the world (Isik et al 2009). However, weed control is recognized as the greatest production-related problem in organic farming systems and thus is one of the major reasons why conventional farmers do not convert to organic production (Kruidhof et al 2009). Use of a cover crop, planting density and sowing date are all considered important for improving the competitiveness of crops against weeds and preventing yield losses in crop plants (Williams 2009;Chauhan and Johnson 2010;Stephenson et al 2010).…”

Interactions between allelochemicals and the microbial community affect weed suppression following cover crop residue incorporation into soil

“…Cover crops can suppress weeds through resource and light competition (Liebman and Dyck 1993;Teasdale 1996), disruption of weed life cycles (Moyer et al 2000), physical suppression by cover crop residues (Moore et al 1994), and release of phytotoxic chemicals associated with cover crop residues (Kruidhof et al 2009;Samedani et al 2013;Teasdale et al 2012). These cover crop residueassociated allelochemicals can suppress weed seed germination (Seigler 1996), seedling establishment (Singh et al 2003;Weston 1996), and weed growth rates (Mirsky et al 2011;Wardle 1995).…”

“…These factors interact to create a Bwindow^of weed suppression potential. Residue-induced suppression of a sensitive plant will take place only when there is an overlap in time between the period of sensitivity of the plant and the window of the suppression potential (Kruidhof et al 2009). Microbial activity may reduce the length of this window if microbe-allelochemical interactions are antagonistic, but microbial activity may extend this window if these interactions are synergistic.…”

Winter mulches and chemical control on weeds in maize

“…(CAMPIGLIA et al, 2010;FAVARATO et al, 2014;KROPFF, 2008;KROPFF, 2009;RADICETTI;MANCINELLI;CAMPIGLIA, 2013). Portanto, a estratégia de controle destas espécies em áreas agrícolas depende das plantas de coberturas utilizadas e das plantas daninhas alvo (KRUIDHOF; BASTIAANS; KROPFF, 2009).…”