Tolerance to weed harrowing in spring barley genotypes

Controlling weeds in spring cereals grown under organic conditions is mostly done by post emergence weed harrowing, where spring tines of the weed harrow control weeds by uprooting and/or covering small weeds plants with soil. In situations with relatively large weed plants and relatively small crop plants, there are increased risks for crop damages by soil coverage or other mechanical damages of the crop leaves. These damages are increasing with increasing weed control intensity, and are resulting in reduced crop growth immediately after weed harrowing. There are risks that the reduced growth reduces final crop yield too. However, there is some evidence that there are varietal differences in the tolerance to weed harrowing. The aim of this study was to estimate the damages by weed harrowing in four pure genotypes and three two- or one three-component mixtures of spring barley, and to analyze if there were differences in tolerance to weed harrowing between the genotypes and mixtures. Results from a two-year field study showed that there were varietal differences in the tolerance to mechanical weed control in the immediate effect as well as the short term effect, however there were marked differences in the immediate and short term effect between the two years. Regarding the long term effect of weed harrowing on yield, there were no significant differences in 2003 but in 2004, Brazil and the three component mixture suffered significantly from weed harrowing while Modena, Otira and Modena+Orthega mixture, seems to benefit from weed harrowing. The reason for these differences is probably due to differences in growth habit at the time for weed harrowing

Forskelle i bygsorters tolerance overfor ukrudtsharvning

dette dokument beskriver resultater fra 2 års forsøg med ukrudtsharvning af 4 sorter og 2 eller 3 komponentblandinger af disse sorter

Tolerance of four spring barley (Hordeum vulgare L.) varieties to weed harrowing

We investigated the tolerance to weed harrowing of four spring barley varieties and examined the possible interactions between varietal weed suppressive ability and two nutrient levels. Tolerance was defined as the combined effect of crop resistance (ability to resist soil covering) and crop recovery (the ability to recover in terms of yield). The weed harrowing strategy was a combination of one pre- and one post-emergence weed harrowing. In terms of yield, the four varieties responded significantly differently to weed harrowing and the response depended on nutrient level. At the lower nutrient level, weed harrowing caused an increase in yield of 4.4 hkg ha-1 for a strong competitor (cv. Otira), while there was no effect on yield at the higher nutrient level. For a weaker competitor (cv. Brazil), weed harrowing caused no change in yield at the lower nutrient level, whereas yield decreased by 6.0 hkg ha-1 at the higher nutrient level. There were marked differences between the weed suppressive ability of the four varieties when not harrowed, with less pronounced but significant differences when harrowed. Weed harrowing did not change the weed suppressive ability of a variety. Varieties that are tall at post-emergence harrowing and have increased density after pre-emergence harrowing, are the ones that benefit most from weed harrowing

Beregning af konkurrenceindeks (KI)

Dokumentet indeholder en beskrivelse af hvordan konkurrenceindekset beregnes i vinterhvede og vårbyg

Nye resultater med bekæmpelse af følfod og tidsler

Rodukrudt udgør et at de største problemer ved økologisk dyrkning. Især tidsler, men også følfod kan være problematiske at bekæmpe og forårsager store udbyttetab. Forsøgsserier peger på, at stubbearbejdning kan undværes ved bekæmpelse af tidsler, mens følfod bekæmpes ved en strategi med gentagne fræsninger

Identification of liver protein targets modified by tienilic acid metabolites using a two-dimensional Western blot-mass spectrometry approach

International audienceA combined approach based on two-dimensional electrophoresis-immuno-blotting and nanoliquid chromatography coupled on-line with electrospray ionization mass spectrometry (nLC-MS/MS) was used to identify proteins modified by a reactive intermediate of tienilic acid (TA). Liver homogenates from rats exposed to TA were fractionated using ultra centrifugation; four fractions were obtained and subjected to 2D electrophoresis. Following transfer to PVDF membranes, modified proteins were visualized after India ink staining, using an anti-serum raised against TA and ECL detection. Immuno-reactive spots were localized on the PVDF membrane by superposition of the ECL image, protein spots of interest were excised, digested on the membrane with trypsin followed by nLC-MS/MS analysis and protein identification. A total of 15 proteins were identified as likely targets modified by a TA reactive metabolite. These include selenium binding protein 2, senescence marker protein SMP-30, adenosine kinase, Acy1 protein, adenosylhomocysteinase, capping protein (actin filament), protein disulfide isomerase, fumarylacetoacetase, arginase chain A, ketohexokinase, proteasome endopeptidase complex, triosephosphate isomerase, superoxide dismutase, dna-type molecular chaperone hsc73 and malate dehydrogenase

Design og sortsvalg i specialforsøg BAROF-WP2 – Ukrudtskonkurrence

Forsøgsplan for forsøg med ukrudtskonkurrenceevne i BAROF

Index beregner hvor godt økologisk vårbyg konkurrerer med ukrudt

Kornafgrøder og –sorter har forskellig evne til at undertrykke ukrudt. Dette skyldes blandt andet sortens evne til at skygge for lyset og optage vand og næringsstoffer. For sorter med en samlet god konkurrenceevne gælder at: de er langstråede de har kraftig bladmasse gennem vækstsæsonen de har en hurtig fremspiring og vækst Denne viden er udnyttet til at beregne et konkurrenceindeks af sorten overfor ukrudt. De fleste forsøg vedrørende disse forskelle er gennemført under konventionelle forhold, hvor niveauet af næringsstoffer er højt, og ukrudt og andre skadevoldere bekæmpes kemisk. Under økologiske forhold vil der oftest være en lavere og mere varierende forsyning med næringsstoffer. For at afklare om dette har en betydning for konkurrenceindekset, er der gennemført nogle forsøg med vårbyg under økologiske forhold i BAROF-projektet