Mechanical weed control in organically grown spring oat and field pea crops
Lithuanian Institute of Agriculture, Joniskelis Research Station,Joniskelis, LT–39301 Pasvalys District, Lithuania; e–mail: firstname.lastname@example.org
Experiments to study the effects of weed harrowing in an organic farming system were carried out during 2005–2007 at the Joniskelis Experimental Station of the Lithuanian Institute of Agriculture on a clay loam Gleyic Cambisol. Spring oat (Avena sativa L.) and field pea (Pisum sativum L.) crops were harrowed once and twice with a Regent spring-tine harrow at pre-emergence, early post-emergence and late post-emergence stages. This study indicates that at early growth stages of crops the uprooting effect of harrowing could be more important for weed control than at late stages. Early post-emergence harrowing (at 2–3 leaf stage) was the most effective for spring oat. Twice (pre-emergence and early post-emergence) harrowing of oat was not more effective than early post-emergence harrowing once, since early harrowing stimulates new sprouting of weeds. Pea crop damage by harrowing was less when the crop was harrowed at late post-emergence (beginning of stem elongation) stage. No difference of crop yield was determined among the treatments.