Interactions between pre- and post-emergence weed harrowing in spring cereals

Pre- and post-emergence weed harrowing were studied in spring cereals in different environments and with two types of harrows in Norway during 2004–2006. The objectives were to investigate interactions between pre and post-emergence weed harrowing and the importance of harrow type. We hypothesised that pre- and post-emergence harrowing interact positively, that a combination gives more stable weed control effects than pre- and post-emergence weed harrowing used alone, and that a harrow type with bent tines is more aggressive and suitable on hard-packed soils than a harrow with strait tines. The results only supported the last of these hypotheses. Post-emergence weed harrowing controlled a certain percentage of the present weeds, and this percentage was not dependent on pre-emergence weed harrowing. On average, pre-emergence harrowing reduced weed density by 26% and weed biomass by 22%, while the average effect of postemergence harrowing was 47% on weed density and 41% on weed biomass. The combined effect of pre- and post-emergence weed harrowing was 61% on weed density and 54% on weed biomass. The combination did not give more stable weed control effects than preand post-emergence weed harrowing used alone. Preemergence harrowing increased the average crop yield by 6.2%, post-emergence harrowing by 4.0% and the combined effect was 10%. Crop yield was mainly increased on hard-packed soils. Weed and crop responses varied strongly among experiments, but the efficacy of pre- and post-emergence weed harrowing was positively correlated across experiments. Weed species composition was of minor importance regarding weed control. The study indicates that one aggressive postemergence cultivation may be as good as one preemergence and one less aggressive post-emergence cultivation. However, little is known about the interactions between cultivation at different crop and weed growth stage

Ugrasharving i korn

Denne undersøkelsen har som målsetning å finne klarere kriterier om det skal harves, når det skal harves, hvordan harva skal stilles inn og hvilke harvtyper og tindetyper som er optimale på forskjellige jordtyper. Videre skal en se på hvordan underkultur kan tilpasses ugrasharving. Resultatene første år er interessante, men det er for tidlig å trekke konklusjoner

Veien til bedre pløying : - en veiledning

All jordarbeiding skal ha som formål å bedre vekstforholda for kulturplantene. Rett utført jordarbeiding er enormt viktig for å få optimal effekt mot rotugras. Pløying legger grunnlag for såbedet og er i seg sjøl et ugrastiltak, vel å merke når plogen har riktig utstyr og er riktig innstilt. Riktig pløying, slik at det er fullstendig gjennomskjæring, at alle velter er like brede og høge, osv er viktig for at alle etterfølgende arbeidsoperasjoner som slodding, harving, såing og senere ugrasharving og radrensing, skal bli optimal. Pløyinga må utføres når jorda er lagelig for å redusere faren for jordpakking. Det er viktig å velge mellom høst eller vårpløying ut i fra faren for erosjon. Dette heftet bør kunne benyttes av alle fordi utstyr, vedlikehold og innstilling i hovedsak er det samme om en har stor eller liten plog. Den faglige bakgrunn for dette heftet baserer seg på forskning vedrørende pløying, men også i stor grad på forfatterens erfaring gjennom mange år. Forfatteren har undervist studenter ved Høgskolen i Hedmark gjennom tretti år, vært trener og dommer i tevlingspløying, og ikke minst holdt utallelige kurser for bønder og andre innen jordbruk. Kursene for praktiske bønder har gitt erfaring i hvor det skorter for de som skal få til en agronomisk riktig pløying.Statens landbruksforvaltning (SLF

Cut fallow to replace black fallow in an organic production system

Couch grass (Elymus repens) has large impact on yield and management strategies in temperate areas of the world. The control is to a large extent based on repeated soil cultivations in organic farming. Our aim was to investigate methods to improve the competitive effect of white clover by management. The hypothesis was that cutting (fragmentation) of the rhizomes by making slits in the soil by a spade (spading) would increase the number of couch grass shoots, thus improve the effect of repeated mowing. We conclude that Cross cutting to 10 cm could reduce the amount of rhizomes, but that the effect is variable. We also conclude that the cross cutting do not improve the effect of mowing. Cross cutting reduce the amounts of couch grass shoots

Rhizome Fragmentation by Vertical Disks Reduces Elymus repens Growth and Benefits Italian Ryegrass-White Clover Crops

Tillage controls perennial weeds, such as Elymus repens, partly because it fragments their underground storage organs. However, tillage is difficult to combine with a growing crop, which limits its application. The aim of this study was to evaluate how soil vertical cutting with minimum soil disturbance and mowing affect the growth and competitive ability of E. repens in a grass–clover crop. A tractor-drawn prototype with vertical disks was used to fragment E. repens rhizomes with minimal soil and crop disturbance. In experiments performed in 2014 and 2015 at a field site close to Uppsala, Sweden, the rhizomes were fragmented before crop sowing (ERF), during crop growth (LRF), or both (ERF+LRF). Fragmentation was combined with repeated mowing (yes/no) and four companion crop treatments (none, Italian ryegrass, white clover, and grass/clover mixture). The results showed that in the grass–clover crop, rhizome fragmentation reduced E. repens rhizome biomass production and increased Italian ryegrass shoot biomass. ERF and LRF both reduced E. repens rhizome biomass by about 38% compared with the control, while ERF+LRF reduced it by 63%. Italian ryegrass shoot biomass was increased by 78% by ERF, 170% by LRF and 200% by ERF+LRF. Repeated mowing throughout the experiment reduced E. repens rhizome biomass by about 75%. Combining repeated mowing with rhizome fragmentation did not significantly increase the control effect compared to mowing alone. We concluded that rhizome fragmentation using vertical disks can be used both before sowing and during crop growth to enhance the controlling effect of grass–clover crops on E. repens

Jordarbeidingsmetodar for korndominerte dyrkingssystem – avlingseffektar

I fleirårige, fastliggande forsøk på Planteforsk Apelsvoll og Kvithamar undersøker ein kva traktortyngde, pløyedjup og køyremåte ved pløying har å seie for jordstruktur og avlingar i økologisk korndyrking. Etter to år er det framleis ikkje store utslag for forsøksfaktorane. Avhengig av vekst og tildels traktortyngde er det sikre utslag for pløyedjup, men avlingsvariasjonen innan felt og delvis mellom år er stort sett større. Djup pløying gav gjennomgåande større kornavlingar enn grunn pløying, men for bygg etter grønngjødsling på Kvithamar, som verken var tilført husdyrgjødsel eller mineralgjødsel, vart avlingane størst med grunn pløying

Veien til bedre pløying : - en veiledning

All jordarbeiding skal ha som formål å bedre vekstforholda for kulturplantene. Rett utført jordarbeiding er enormt viktig for å få optimal effekt mot rotugras. Pløying legger grunnlag for såbedet og er i seg sjøl et ugrastiltak, vel å merke når plogen har riktig utstyr og er riktig innstilt. Riktig pløying, slik at det er fullstendig gjennomskjæring, at alle velter er like brede og høge, osv er viktig for at alle etterfølgende arbeidsoperasjoner som slodding, harving, såing og senere ugrasharving og radrensing, skal bli optimal. Pløyinga må utføres når jorda er lagelig for å redusere faren for jordpakking. Det er viktig å velge mellom høst eller vårpløying ut i fra faren for erosjon. Dette heftet bør kunne benyttes av alle fordi utstyr, vedlikehold og innstilling i hovedsak er det samme om en har stor eller liten plog. Den faglige bakgrunn for dette heftet baserer seg på forskning vedrørende pløying, men også i stor grad på forfatterens erfaring gjennom mange år. Forfatteren har undervist studenter ved Høgskolen i Hedmark gjennom tretti år, vært trener og dommer i tevlingspløying, og ikke minst holdt utallelige kurser for bønder og andre innen jordbruk. Kursene for praktiske bønder har gitt erfaring i hvor det skorter for de som skal få til en agronomisk riktig pløying

Vertical rhizome disking to reduce Elymus repens (quackgrass) abundance in grass-clover leys

Elymus repens is a problematic perennial weed in annual crops, grasslands and leys. Rhizome fragmentation by vertical disking can potentially reduce E. repens abundance with minimal tillage, but data are lacking on its efficiency in forage production. In a two-year study (2017-2018, 2018-2019) conducted in two forage grassclover leys that were mostly weed-free except for large E. repens populations, this study examined effects on forage yield, botanical composition, and E. repens rhizome biomass of rhizome fragmentation at significant growth initiation in spring (early rhizome fragmentation, ERF) and/or when conditions allowed after the first forage cut (late rhizome fragmentation, LRF). Cold, wet springs and hard, dry soil in summer delayed treatment in both treatment years, to late spring (ERF) and late summer/early autumn (LRF). In the treatment year, ERF reduced first-cut forage yield by 44% compared with no rhizome fragmentation, while LRF decreased secondand third-cut yield by 24% and 53%, respectively. In the year after treatment, ERF increased total forage yield by on average 10%, while LRF had no effect. Over both years, combined forage yield was reduced by 11% by ERF and 4% by LRF. Both treatments reduced E. repens rhizome biomass, but inconsistently (ERF by 25% in one year only, LRF by 24% at one of two sites). ERF reduced E. repens incidence in forage by 10% in the treatment year, but had no effect in the following year. Thus, rhizome fragmentation by vertical disking can reduce E. repens abundance in grass-clover leys, but the effect is inconsistent and forage yield can be impaired, especially in swards with much E. repens. Moreover, disking is hampered by hard, dry soil conditions

Control of perennial weeds in spring cereals through stubble cultivation and mouldboard ploughing during autumn or spring

Creeping perennial weeds are of major concern in organically grown cereals. In the present study, the effects of different timing of mouldboard ploughing with or without a preceding stubble cultivation period, on weeds and spring cereals were studied. The experiments were conducted at two sites in Norway during a two and three-year period, respectively, with the treatments repeated on the same plots. The soil cultivation treatments were a stubble disc-harrowing cultivation period followed by mouldboard ploughing and only mouldboard ploughing. The timing of the treatments were autumn or spring. The density and biomass of the aboveground shoots of Cirsium arvense (L.) Scop., Elymus repens (L.) Gould, Sonchus arvensis L. and Stachys palustris L. as well as the total aboveground biomass of the spring cereal crop (oats) were assessed. The control efficiency of C. arvense and S. arvensis was closely related to timing of the cultivation treatments. Cultivation in spring decreased the population of C. arvense and S. arvensis compared to autumn cultivation. For E. repens, timing of the treatments had no significant effect: the important factor was whether stubble cultivation was carried out (best control) or not. The overall best strategy for controlling the present perennial weed population was stubble cultivation followed by ploughing in spring. However, the associated relative late sowing of the spring cereal crop and lowered crop biomass, were important drawbacks.publishedVersio

Control of Elymus repens by rhizome fragmentation and repeated mowing in a newly established white clover sward

Control of perennial weeds, such as Elymus repens, generally requires herbicides or intensive tillage. Alternative methods, such as mowing and competition from subsidiary crops, provide less efficient control. Fragmenting the rhizomes, with minimal soil disturbance and damage to the main crop, could potentially increase the efficacy and consistency of such control methods. This study's aim was to investigate whether fragmenting the rhizomes and mowing enhance the control of E. repens in a white clover sward. Six field experiments were conducted in 2012 and 2013 in Uppsala, Sweden, and Ås, Norway. The effect of cutting slits in the soil using a flat spade in a 10 × 10 cm or 20 × 20 cm grid and the effect of repeated mowing were investigated. Treatments were performed either during summer in a spring-sown white clover sward (three experiments) or during autumn, post-cereal harvest, in an under-sown white clover sward (three experiments). When performed in autumn, rhizome fragmentation and mowing reduced E. repens shoot biomass, but not rhizome biomass or shoot number. In contrast, when performed in early summer, rhizome fragmentation also reduced the E. repens rhizome biomass by up to 60%, and repeated mowing reduced it by up to 95%. The combination of the two factors appeared to be additive. Seasonal differences in treatment effects may be due to rhizomes having fewer stored resources in spring than in early autumn. We conclude that rhizome fragmentation in a growing white clover sward could reduce the amount of E. repens rhizomes and that repeated mowing is an effective control method, but that great seasonal variation exists.publishedVersio