Harrowing timing for winter wheat and spring barley under organically growing conditions

A. Auškalnis and O. Auškalnienė

Lithuanian Institute of AgricultureInstituto Alėja 1, LT – 58344, Akademija, Kėdainiai distr.; e-mail: albinas@lzi.lt

Abstract:

Field trials were conducted over the period of 2005–2007 at the Lithuanian Institute of Agriculture to test the efficacy of harrowing on weeds at different growth stages of ecologically grown winter wheat and spring barley. The main weeds in winter wheat were: Lamium sp., Chenopodium album, Tripleurospermum inodorum, Capsella bursa-pastoris and in spring barley Ch.album, Sinapis arvensis, Stellaria media, T. inodorum. The weeds most vulnerable to harrowing in winter wheat were: Veronica sp., Chenopodium album and Capsella bursa pastoris. Chenopodium album and Sinapis arvensis were vulnerable to harrowing in spring barley. Early harrowing pre-emergence followed with harrowing at the 3–4 leave stage of spring barley was the most optimal.Winter wheat grain yield reduction tendencies were obtained in plots harrowed threetimes. No statistical difference in spring barley grain yield was found among the treatments. The decrease in weed number and mass depended on harrowing timing and frequency, meteorological conditions and weed species composition.

Key words:

Mechanical weed control in organically grown spring oat and field pea crops

A. Velykis, S. Maiksteniene, A. Arlauskiene, I. Kristaponyte and A. Satkus

Lithuanian Institute of Agriculture, Joniskelis Research Station,Joniskelis, LT–39301 Pasvalys District, Lithuania; e–mail: velykisalex@gmail.com

Abstract:

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.

Key words:

clay loam, crop yield, field pea, harrowing, organic farming, spring oat, weed