Intensifying bare fallow strategies to control Elymus repens in organic soils

Authors

• Timo Lötjönen Natural Resources Institute Finland (Luke), Tutkimusasemantie 15, FI-92400 Ruukki, Finland http://orcid.org/0000-0003-1440-8165
• Jukka Salonen Natural Resources Institute Finland (Luke), Tietotie 4, FI-31600 Jokioinen, Finland

DOI: https://doi.org/10.23986/afsci.55533

Keywords:

fallowing, Kvick-Finn, mechanical control, organic farming, perennial weed, tillage

Abstract

Perennial weeds are an increasing challenge in organic farming in the Nordic countries. The aim of this study was to compare different tillage methods in the control of Elymus repens by using two intensified bare fallow strategies. Two field experiments consisted of three ploughing methods and seven fallow methods. The experiments were carried out in organic soils in Central Finland. The methods applied in the brief fallow before cereal sowing (exp. 1) were not effective enough against E. repens. Due to wet weather conditions in the spring the fallow period was limited to two weeks in both years, which did not seem to be enough time. In the late summer fallow after ley (exp. 2), the Kvick-Finn weed-cultivator destroyed E. repens very effectively; on average 5% of E. repens remained alive in the barley crop in the autumn of the following year. After use of ordinary cultivators 10% of E. repens remained alive, after use of the spade harrow 25% and after frequent mowing over 50% remained alive, respectively. As a result of effective E. repens control, barley yield was about 1000 kg ha-1 higher than without any fallow. In conclusion, effective control of E. repens is achieved with proper machinery and repeated treatments at the optimal time.