Suppression of Digitaria sanguinalis and Amaranthus palmeri using autumn‐sown glucosinolate‐producing cover crops in organically grown bell pepper

Abstract

Summary Experiments were conducted to compare growth characteristics, biomass production and glucosinolate content of seven autumn‐planted glucosinolate‐producing cover crops that were terminated the following spring. The control of Digitaria sanguinalis and Amaranthus palmeri following cover crop incorporation into soil was characterised and fruit yields of bell pepper transplanted into cover crop‐amended soil were determined. Differences in glucosinolate concentration and composition were noted between cover crop roots and shoots and among cover crops. Total biomass production by cover crops ranged from 103 g m−2 for garden cress to 894 g m−2 for Indian mustard (F‐E75), but cover crop biomass was not correlated with D. sanguinalis and A. palmeri control. D. sanguinalis and A. palmeri control in bell pepper varied by cover crop. D. sanguinalis control by cover crops ranged from 38% to 79%, and A. palmeri control was 23% to 48% at 4 weeks after transplanting (WATP) bell pepper in 2004. D. sanguinalis control was positively correlated with total glucosinolate production, but A. palmeri control was not. D. sanguinalis control in 2005 ranged from 0% to 38% at 2 WATP. In the absence of weeds, cover crops did not negatively affect fruit yields which were often higher than in the absence of a cover crop. Glucosinolate‐producing cover crops are not a stand‐alone weed management strategy, but some will provide early season control of D. sanguinalis and A. palmeri without having a negative effect on transplanted bell pepper.

Kochia Suppression with Cover Crops in Southwestern Kansas

“…Enhancing fallow with a cover crop may contribute to reducing weed emergence and biomass. For example, the presence of a cover crop or dry biomass as residue reduced the number of emerged seedlings, delayed emergence, and increased the susceptibility of emerged seedlings to control measures (Crutchfield et al, 1986; Haramoto and Gallandt, 2005; Isik et al, 2009; Norsworthy et al, 2007; Teasdale et al, 2005). The possibility of using a competitive cover crop instead of or in combination with chemical control could reduce kochia emergence and biomass accumulation.…”

Advances and Trends in Organic Fruit and Vegetable Farming Research

“…Most of the studies concerned weed control using cover crops (Fisk et al 2001;Nagabhushana et al 2001;Ngouajio et al 2003;Ngouajio and Mennan 2005;Norsworthy et al 2007;Isik et al 2009) and mechanical or thermal methods (Aikman et al 1995;Ates 2007;Peruzzi et al 2007;Ascard and Fogelberg 2008;Raffaelli et al 2011;Koller and Vieweger 2012). For example, cover crops such as hairy vetch, ryegrass, oat, and common vetch reduced weed infestation in organic pepper by 87-91% (dry biomass), whereas clover was a poor competitor (Isik et al 2009).…”

Effects of alternative winter cover cropping systems on weed suppression in organically grown tomato (Solanum lycopersicum)

“…Therefore, organic farming systems need reliable and highly effective weed management strategies based on ecological approaches. One of the most successful systems is the use of cereal and/or legume cover crops for physical and allelopathic weed control (Isık et al 2009a, b;Mennan et al 2006Mennan et al , 2009Ngouajio and Mennan 2005;Norsworthy et al 2007;Teasdale 1996).…”