The effect of mulches on Elytrigia repens spreading under conditions of organic agriculture

Abstract

Elytrigia repens is the most important and widely spread perennial weed in Lithuania. Infestation with E. repens in organic agriculture is an increasing problem in many parts of Europe. Non-chemical weed management strategies against E. repens, based on cultivation tactics and different mulching, have received very high attention for many years. The two factor stationary field experiment was carried out at the Experimental Station of the Aleksandras Stulginskis University. The influence of organic mulches and different thickness of mulch layer on weed density was investigated in 2004–2009, the residual effect of the mulches and mulch layer was studied in 2010–2012. At the beginning of the experiment higher density of E. repens was estimated in plots with straw mulch and lower in plots mulched with peat and grass mulch. In 2007–2009 all investigated organic mulches reduced E. repens emergence. Peat, sawdust and grass had the strongest influence on the decrease of E. repens regrowth. Significantly higher density of E. repens sprouts was estimated in experimental plots mulched with 5 cm mulch layer compared with this in plots mulched with 10cm mulch layer during 2004–2009 except 2007. The residual effect of all examined organic mulches on E. repens spreading was unequal. The previously six years used and incorporated organic mulches did not significantly decrease E. repens numbers in 2010–2012 because they do not mechanically suppress weed emergence. The residual effect of mulch layers on E. repens sprout numbers was not significant. A tendency of decreased densities of E. repens was estimated during the first two years of the mulch residual effect studies.

Keywords

• Elytrigia repens
• organic farming
• organic mulch
• residual effect of mulch