Physical and Cultural Weed Control Working Group of - European ...

9 th EWRS Workshop on Physical and Cultural Weed Control 44
Samsun, Turkey, 28 – 30 March 2011
Effects of cover crops on weed populations in hazelnut (Corylus avellana L.)
Husrev Mennan 1 , Dogan Isık 2 , Emine Kaya Altop 1 , Unal Budak 1
1 Department of Plant Protection, Agriculture Faculty, Ondokuz Mayis University, 55139 Samsun,
Turkey
2 Black Sea Agricultural Research Institute, Samsun, Turkey
The cultivated hazelnut (Corylus avellana L.) is native to the Black Sea coast of northern
Europe, and Turkey is one of the few countries in the world with a suitable climate for its
production. The relatively high rainfall and fertile soils of hazelnut orchards in the Black Sea region
favour establishment of a wide range of annual and perennial weed species. Weed management in
hazelnut orchards is necessary to eliminate competition, conserve nutrients for the trees, and
improve hand harvesting efficiency. Weed management in hazelnut is a major production challenge,
with glyphosate being the main herbicide used. Weed control without the use of herbicides is an
expensive and time-consuming task in orchard management. Mechanical weed control methods are
thought to be environment friendly and could help to prevent public pressure to reduce herbicide
use in hazelnut orchards. Orchard floor management practices such as the use of cover crops either
alone or combined with mechanical methods, could have significant effects on weed management in
hazelnut production.
Field trials were conducted from 2009 to 2010 to evaluate effects of cover crops on weed
populations. The cover crop treatments consisted of Lolium perenne L., Vicia villosa Roth.,
Medicago sativa L., Onobrychis sativa L., Brassica napus var. oleifera L., and Brassica rapa L.
Cover crop seeds were broadcast and incorporated into the soil with a shallow cultivation. All cover
crops or weeds growing in the fallow plots were killed mechanically by mowing on April 24, 2010.
To determine the suppressive effects of the cover crops during growing season, weed species, weed
density, and total weed dry biomass were assessed at 14, 28, and 56 DAI from all plots using a 50
by 50-cm quadrat placed randomly in the plots. Additionally, visual estimates of seedling
emergence were conducted at 28 and 56 DAI using a scale of 0 to 100%, where 0% represents no
weed control (fallow treatment) and 100% complete weed control. After 56 DAI the entire
experiment was hand weeded to eliminate further weed competition.
Biomass (kg ha-1)
4000
3500
3000
2500
2000
1500
1000
500
0
L. perenne V. villosa M. sativa O. sativa B. napus B. rapa
Cover crops
Figure 1. Biomass production (kg ha -1 ) of cover crops prior to incorporation in 2009 and 2010.
Vertical lines represent standard errors of the means.
2009
2010