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The effect of harrowing on the weediness and yield of spring barley in organic farming
2005
Svarta, A.(Latvia Univ. of Agriculture, Skriveri, Aizkraukle reg. (Latvia). Agency Research Institute of Agriculture)E-mail:svarta@inbox.lv
Field trials were carried out on organic farming fields at the Research Institute of Agriculture of the Latvia University of Agriculture (LLU). The influence of harrowing (without harrowing, before emergence, at the stage of tillering, before emergence and at the stage of tillering) depending of pre-crop (red clover, winter rye for grain, bare fallow and green manure) and use of stable manure (60 t haE-1 or without) on the weediness and yield of spring barley 'Sencis' was tested during 2003-2004. In spring barley, 18 species of weeds were established at the stage of earing during 2003-2004. The most widespread of perennial weeds were Elytrigia repens (L.) Nevski and Sonchus arvense L. The dominant annual weeds were Chenopodium album L., Stellaria media L., Capsella bursa-pastoris L., Polygonum spp., and Matricaria inodorum L. The number of annual weeds at the stage of earing differed during the years 50-160 (in 2003) and 33-118 (in 2004) annual weeds per mE-2. The influence of harrowing on the number of annual weeds was different during the testing years. The influence of harrowing on the grain yield was negligible during 2003 and 2004.
Afficher plus [+] Moins [-]Nitrogen, phosphorus and potassium influence on infections by arbuscular mycorrhizal fungi in Dactylis glomerata roots
2005
Druva-Lusite, I.(University of Latvia, Riga (Latvia))E-mail:mycorrhiza@gmail.com | Liepina, L.(University of Latvia, Riga (Latvia))E-mail:ligita@mail.lubi.edu.lv | Skujins, J.(University of Latvia, Riga (Latvia)) | Antonijs, A.(Latvia Univ. of Agriculture, Skriveri, Aizkraukle reg. (Latvia). Skriveri Research Centre)
The aim of this research was to compare effects of fertilization with various ratios of N, P and K (N:P:K) on arbuscular mycorrhizal fungi (AMF) infection in roots of Dactylis glomerata in Ca-carbonate (limed) and non-limed meadow plots at the Research Centre of Skriveri, Latvia University of Agriculture. Dactylis glomerata roots were excavated from variously fertilizer plots, a minimum 3 root samples per plot and analysed for two consecutive years. Arbuscular mycorrhizal fungi infection rates were estimated according to accepted scoring tables used for determination of AMF colonization.
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