Zahra Bitarafan
Research Scientist
Attachments
Curriculum VitaeAbstract
No abstract has been registered
Abstract
Yield maps give farmers information about growth conditions and can be a tool for sitespecific crop management. Combine harvesters may provide farmers with detailed yield maps if there is a constant flow of a certain amount of biomass through the yield sensor. This is unachievable for grass seeds because the weight of the intake is generally too small to record the variation. Therefore, there is a need to find another way to make grass seed yield maps. We studied seed yield variation in two red fescue (Festuca rubra) fields with variation in management and soil fertility, respectively. We estimated five vegetation indices (VI) based on RGB images taken from a drone to describe yield variation, and trained prediction models based on relatively few harvested plots. Only results from the VI showing the strongest correlation between the index and the yield are presented (Normalized Excess Green Index (ExG) and Normalized Green/Red Difference Index (NGRDI)). The study indicates that it is possible to predict the yield variation in a grass field based on relatively few harvested plots, provided the plots represent contrasting yield levels. The prediction errors in yield (RMSE) ranged from 171 kg ha-1 to 231 kg ha-1, with no clear influence of the size of the training data set. Using random selection of plots instead of selecting plots representing contrasting yield levels resulted in slightly better predictions when evaluated on an average of ten random selections. However, using random selection of plots came with a risk of poor predictions due to the occasional lack of correlation between yield and VI. The exact timing of unmanned aerial vehicles (UAVs) image capture showed to be unimportant in the weeks before harvest.
Abstract
No abstract has been registered
Abstract
Material exiting the harvester is composed of chaff and straw. Chaff is a by-product of grain harvest comprises weed seeds and husk. Harvest Weed Seed Control (HWSC) systems aim at collecting and/or killing weed seeds in the chaff fraction during crop grain harvest. If chaff is removed or processed via impact mills or concentrated in a narrow zone in the field and collected, the overall weed infestation may be reduced in the following years. Chaff may be used as a new biomass feedstock, for example, as a renewable energy source, material for construction ( e.g. , insulating boards, cardboard, bedding), soil improvement ( e.g ., mulch, mushroom compost), and for agricultural purposes ( e.g. , weed growth inhibitor, animal diet). Using chaff directly is unfavorable because of its low bulk density. Therefore, compressing chaff into pellets can improve its handling. In this preliminary study, we assessed how pelletizing would affect the germinability of weed seeds in the chaff pellets. Whole wheat chaff and fine wheat chaff sieved were mixed with seeds of the two weed species scentless mayweed ( Tripleurospermum inodorum (L.) Sch.Bip.) and cornflower ( Centaurea cyanus L.), respectively. While 22% of T. inodorum seeds and 59% of C. cyanus seeds in wheat chaff samples were able to germinate, no weed seeds germinated from moist pelletized original and fine wheat chaff samples. The study indicates a low risk of spreading weed seeds with pelletized chaff probably because the heating during the pelletizing process kills the weed seeds.
Abstract
Harvest Weed Seed Control (HWSC) systems are used to collect and/or kill weed seeds retained on the weed plants at crop harvest. The effect of HWSC methods depends on the weeds seed retention at harvest. Therefore, delay in crop harvest reduces the efficiency of HWSC. In 2018, we studied the seed production and shedding pattern of Alopecurus myosuroides in a semi-field experiment in Taastrup, Denmark, to find the seed shedding time range of this species. In 2017 and 2018, we also followed the seed shedding pattern of A. myosuroides in a wheat field. Seeds of A. myosuroides were planted in pots in a greenhouse with a constant temperature of 5°C. In December 2017, the seedlings were transplanted in a box (120 × 80 cm2) located outdoor. In spring 2018, the number of plants was reduced to 14 providing a space of 685 cm2 for each plant. We surrounded each plant with a porous net to collect the seeds. The nets were checked once a week to record the beginning of the seed shedding period. Hereafter, seeds were collected weekly using a portable vacuum cleaner. Plants in the box started seed shedding in the second week of June and seed shedding continued for 12 weeks (end of August). In the wheat field, A. myosuroides plants surrounded by a net started to shed seeds in the third week of June and continued until wheat harvest on 31 July in 2017 and in the second week of July and continued until wheat harvest on 15 August in 2018. We found a significant difference between the weekly number of shed seeds in all three experiments (P
Authors
Maryam Mirahmad Shahrzad Mohseni Ozra Tabatabaei-Malazy Fataneh Esmaeili Sudabeh Alatab Roodabeh Bahramsoltani Hanieh-Sadat Ejtahed Husseyn Qulami Zahra Bitarafan Babak Arjmand Elahe NazeriAbstract
Background Inflammation is a double-edged sword in the pathophysiology of chronic diseases, such as type 2 diabetes mellitus (T2DM). The global rise in the prevalence of T2DM in one hand, and poor disease control with currently-available treatments on the other hand, along with an increased tendency towards the use of natural products make scientists seek herbal medicines for the management of diabetes and its complications by reducing C-reactive protein (CRP) as an inflammatory marker. Purpose To systematically review the literature to identify the efficacy of various medicinal plants with antioxidative and anti-inflammatory properties considering their effect on CRP in animal models of T2DM. Study design systematic review. Methods Electronic databases including PubMed, Scopus, Web of Science and Cochran Library were searched using the search terms “herbal medicine”, “diabetes”, “c-reactive protein”, “antioxidants” till August 2021. The quality of evidence was assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE's) tool. The study protocol was registered in PROSPERO with an ID number CRD42020207190. A manual search to detect any articles not found in the databases was also made. The identified studies were then critically reviewed and relevant data were extracted and summarized. Results Among total of 9904 primarily-retrieved articles, twenty-three experimental studies were finally included. Our data indicated that numerous herbal medicines, compared to placebo or hypoglycemic medications, are effective in treatment of diabetes and its complications through decreasing CRP concentrations and oxidative stresses levels. Medicinal plants including Psidium guajava L., Punica granatum L., Ginkgo biloba L., Punica granatum L., Dianthus superbusn L.. Moreover, Eichhornia crassipes (Mart.) Solms, Curcuma longa L., Azadirachta indica A. Juss., Morus alba L., and Ficus racemosa L. demonstrated potential neuroprotective effects in animal models of diabetes. Conclusion Hypoglycemic medicinal plants discussed in this review seem to be promising regulators of CRP, and oxidative stress. Thus, these plants are suitable candidates for management of diabetes’ complications. Nevertheless, further high-quality in vivo studies and clinical trials are required to confirm these effects.
Abstract
Galera, Matrigon 72SG and their parallel products are approved for weed control in oilseed rape every fourth years. In 2017, clopyralid, which is the active component in the herbicides, was found in Danish honey for the first time when honey from 2016 and 2017 was tested. The maximum acceptable residue level for clopyralid in honey has not been verified scientifically but is set at 0.05 mg/kg, which is not considered harmful to humans. However, 0.1 mg/kg releases a ban on sale of honey. In several of the tested honey samples from both years the amount of clopyralid was higher than 0.1 mg/kg. As nearly 50% of the Danish honey stems from nectar collected from rapeseed the use of clopyralid in oilseed rape poses a very serious economic problem for Danish beekeepers, and already in 2017, the sale of several spring honey lots was rejected. In 2019 and 2020, we tested the following hypotheses 1) nectar and pollen, collected from flowers of winter oilseed rape sprayed with clopyralid according to the regulations may contain clopyralid; 2) honey and pollen collected from beehives placed next to winter oilseed rape fields sprayed with clopyralid according to the regulations may contain clopyralid. Residues of clopyralid were found in all nectar, pollen and honey samples from treated plots and fields. In a large part of the samples, more than 0.1 mg clopyralid/kg was detected, which would have resulted in a ban on the sale of honey. The perspectives of the results are discussed.
Abstract
Clopyralid is a systemic herbicide used in oilseed rape and other crops. It was found in Danish honey from 2016 in concentrations exceeding the maximum residue level (MRL) of 0.05 mg kg−1. About 50% of the Danish honey is based on nectar from winter oilseed rape. In 2019 and 2020, winter oilseed rape fields were sprayed with clopyralid just before the assigned spraying deadline. At flowering, nectar and pollen samples were collected and the content of clopyralid was measured. Honey and pollen samples were also collected from beehives next to ten conventional winter oilseed rape fields sprayed with clopyralid. Clopyralid was found in nectar and pollen from the experimental fields, and in honey and pollen from beehives next to the conventional fields. For most samples the content in nectar and honey exceeded the MRL. The concentrations found, may not pose any health risk for consumers, as the MRL is based on the original detection limit and not on toxicological tests. However, it can have a significant economical consequence for the beekeepers, who are not allowed to sell the honey if the concentration of clopyralid exceeds 0.1 mg kg−1. Reducing the acceptable applicable rate of clopyralid or implementing an earlier deadline for spraying of clopyralid may reduce the risk of contaminating bee food products. However, if it is not possible to obtain a satisfactory effect of clopyralid on the weed flora under these conditions, spraying with pesticides containing clopyralid should be restricted in winter oilseed rape. Determination of an MRL value based on toxicological tests might result in a higher value and make it acceptable selling the honey containing higher levels of clopyralid.
Abstract
Seed production is an important element of weed population dynamics, and weed persistence relies upon the soil seed bank. In 2017 and 2018, we studied the relationship between the aboveground dry biomass of common weed species and their seed production. Weeds were selected randomly in the fields, and we surrounded the plants with a porous net to collect shed seeds during the growth season. Just before crop harvest, weeds were harvested, the plants’ dry weights were measured, and the number of seeds retained on the weeds was counted. A linear relationship between the biomass and the number of seeds produced was estimated. This relationship was not affected by year for Avena spica-venti, Chenopodium album, Galium aparine, or Persicaria maculosa. Therefore, the data of the two seasons were pooled and analysed together. For Alopecurus myosuroides, Anagallis arvensis, Capsella bursa-pastoris, Geranium molle, Polygonum aviculare, Silene noctiflora, Sonchus arvensis, Veronica persica, and Viola arvensis, the relationship varied significantly between the years. In 2017, the growing season was cold and wet, and the slope of the regression lines was less steep than in the dry season in 2018 for most species. Capsella bursa-pastoris was the most prolific seed producer with the steepest slope.
Abstract
VIPS is a technology platform for prognosis, monitoring and decision support for integrated pest management in crops in Norway. The service facilitates access to a Danish decision support tool, IPMwise, for the management of weeds. This tool, called VIPS-weeds in Norway, is adjusted to the Norwegian conditions for cereals. VIPS-weeds selects and adjusts the dose of herbicides according to weed species, weed density and temperature. The tool is being tested each year for local adaptations and updating. In 2021, four experiments were performed in spring wheat and barley. The experiments were designed in completely randomised blocks with three replications, and each included a control (unsprayed), a VIPS-weeds, and an adviser choice plot as well as plots for a variety of herbicides that are common in these crops. The weed species and density, development stage and possible herbicide resistance of each species in the control plots as well as crop information and temperature data were registered in VIPS-weeds three days before the normal spraying time. The suggested herbicides (set to be suggested based on the price) were applied to the VIPS-weeds plots. The effect of suggested herbicides and their dose was assessed as the reduction of weed coverage (%) in sprayed plots compared to the control plots 3-4 weeks after spraying. The average efficacy targets for the weed species (observed at least in two fields) Spergula arvensis, Viola sp., Stellaria media, Galeopsis sp., Chenopodium album, and Fumaria officinalis were predicted to be at 91, 84, 65, 83, 80, and 72% respectively, by VIPS-weeds. The results showed an average efficacy of 45, 58, 79, 80, 91 and 82% for these weeds, respectively. The VIPS-weeds solution was economically reasonable and gave similar results as adviser choice in terms of weed control and yield.
Abstract
Harvest Weed Seed Control (HWSC) systems are used to collect and/or kill weed seeds in the chaff fraction during grain harvest. While collecting chaff reduces the weed infestation in the following years, a new biomass feedstock is created. Chaff mainly consists of husk and straw. There is a potential energetic utilization of chaff. It can also be used as a material for construction (e.g., insulating boards, cardboard, bedding), soil improvement (e.g., mulch, mushroom compost) and agricultural use (e.g., weed growth inhibitor, animal diet). Using chaff directly is unfavorable because of low bulk density; therefore, compressing chaff into pellets optimizes its handling. We have assessed how pelletizing would affect germination of weed seeds bearing in the chaff if the collected chaff is pelletized for further utilization. To test this, we mixed original wheat chaff and fine wheat chaff (pretreated by sieving) with each of the weed species Tripleurospermum inodorum and Centarea cyanus seeds separately. Approximately 2000 seeds of each weed species were added to 2500 g of chaff (20 % moisture). Samples were pelletized using the Kahl Pelleting Press 14-175. Each treatment was replicated four times. Afterwards pelletized samples were spread evenly on the soil surface in 14 × 16 cm boxes and covered by a thin layer of soil/sand. Unpelletized chaff samples were used as control. Boxes were placed in greenhouse and watered from the bottom and seed germination was followed for a month. While on average 22 and 59 % seed germination of T. inodorum and C. cyanus were observed in wheat chaff control samples respectively, no weed seed germination was observed in pelletized fine and original wheat chaff samples. Consequently, we find that the pelletizing process of collected chaff destroys the weed seeds in it.
Abstract
Reusing soil can reduce environmental impacts associated with obtaining natural fresh soil during road construction and analogous activities. However, the movement and reuse of soils can spread numerous plant diseases and pests, including propagules of weeds and invasive alien plant species. To avoid the spread of barnyardgrass in reused soil, its seeds must be killed before that soil is spread to new areas. We investigated the possibility of thermal control of barnyardgrass seeds using a prototype of a stationary soil steaming device. One Polish and four Norwegian seed populations were examined for thermal sensitivity. To mimic a natural range in seed moisture content, dried seeds were moistened for 0, 12, 24, or 48 h before steaming. To find effective soil temperatures and whether exposure duration is important, we tested target soil temperatures in the range 60 to 99 C at an exposure duration of 90 s (Experiment 1) and exposure durations of 30, 90, or 180 s with a target temperature of 99 C (Experiment 2). In a third experiment, we tested exposure durations of 90, 180, and 540 s at 99 C (Experiment 3). Obtaining target temperatures was challenging. For target temperatures of 60, 70, 80, and 99 C, the actual temperatures obtained were 59 to 69, 74 to 76, 77 to 83, and 94 to 99 C, respectively. After steaming treatments, seed germination was followed for 28 d in a greenhouse. Maximum soil temperature affected seed germination, but exposure duration did not. Seed premoistening was of influence but varied among temperatures and populations. The relationships between maximum soil temperature and seed germination were described by a common dose–response function. Seed germination was reduced by 50% when the maximum soil temperature reached 62 to 68 C and 90% at 76 to 86 C. For total weed control, 94 C was required in four populations, whereas 79 C was sufficient in one Norwegian population.
Abstract
Established invasive alien plant species make it difficult and costly to move and make use of infested soil in public and private construction work. Stationary soil steaming as a non-chemical control method has the potential to disinfect soil masses contaminated with seeds and other propagative plant materials. The outcome can vary depending on steaming temperature and duration. Higher temperatures and longer durations are relatively more efficient but may also have side-effects including change in soil physical and chemical characteristics. Barnyard grass (Echinochloa crus-galli) is among troublesome invasive species in Norway. We have tested different steam duration at 99°C to find the possible lowest effective exposure duration for killing seeds of this annual grass species. Four replications of 40 barnyard grass dry seeds of one population were placed in polypropylene-fleece bags (9*7 cm), moistened for 12 hours, and covered by the soil at a depth of 7 cm in 60*40*20 cm boxes. The boxes with soil and bags were steamed at 99°C for 1.5, 3 and 9 min. The bags including steamed seeds were taken out, opened, placed on soil surface in pots and covered by a thin layer of soil. The pots were placed in greenhouse and watered from below and seed germination was followed for a month. Moistened non-steamed seeds were used as control. It was shown that steaming at 99°C gave 0% germination indicating that 100% of the seeds were killed regardless of exposure duration while in the control seed germination was 100%. Consequently, to achieve an efficacy of 100%, exposure duration of 1.5 min would be enough. Finding the lowest possible steam temperature and exposure duration to get the highest possible seed killing in a seed mixture of different plant species as well as other factors to increase the heat transferability are under investigation. Keywords: Echinochloa crus-galli; Resource recovery; Steaming temperature and duration; Thermal soil disinfection
Abstract
Soil disinfestation by steaming is being reconsidered for its efficiency in controlling or even eradicating pathogens, nematodes and weed seeds, particularly to avoid excess use of pesticides. Most weeds within a field result from seeds in the soil seedbank and therefore management of weed seeds in the soil seedbank offers practical long-term management of weeds, especially those difficult to control. We investigated the possibility of thermal control of seeds of grass weeds Bromus sterilis (barren brome) and Echinochloa crus-galli (barnyardgrass) using a prototype of a soil steaming device. Five different soil temperatures of 60, 70, 80, 90 and 99°C with an exposure duration of 3 min were tested. Four replications of 50 seeds of each species were placed in polypropylene-fleece bags. Bags in the same replicate of each target temperature were placed at the bottom of one plastic perforated basket container and covered by a 7-cm soil layer. Each basket was placed in the steaming container and steam was released from the top and vacuumed from the bottom of the container. Soil temperature was monitored by 10 thermocouples and steaming was stopped when 5 of the thermocouples had reached the target temperature. The basket was then removed from the steaming container after 3 min exposure time. Bags were taken out, opened, placed on soil surface in pots and covered by a thin layer of soil. Seed germination was followed for 8 weeks in the greenhouse. Non-steamed seeds were used as controls. It was shown that soil temperatures of 60, 70, 80, 90 and 99°C lasting for 3 min reduced the seed germination of barren brome by 83, 100, 100, 95 and 100% and seed germination of barnyardgrass by 74, 69, 83, 89 and 100% respectively, compared to the controls. Germination rate of control seeds were 94 and 71% for barren brome and barnyardgrass, respectively. These results show a promising seed mortality level of these two weed species by steaming and that steam is a potential method to control weed seeds, however further studies are needed to investigate the effect of other factors such as soil type and moisture content. Keywords: Non-chemical weed control, thermal soil disinfection, weed seedbank
Abstract
Invasive plant propagative material can be introduced to new regions as contaminants in soil. Therefore, moving soil should be done only when the soil has been verified to be free of invasive species. Stationary soil steaming as a non-chemical control method has the potential to disinfect soil masses contaminated with invasive species. We investigated the possibility of thermal control of propagative material of Bohemian knotweed (Reynoutria × bohemica) in two experiments using a prototype of a soil steaming device. Five soil temperatures of 60, 70, 80, 90 and 99 °C with an exposure duration of 3 min were tested. In each replicate and target temperature, rhizome cuttings containing at least two buds and shoot clumps were placed at the bottom of a plastic perforated basket and covered by a 7-cm soil layer. Each basket was placed in the steaming container and steam was released from the top and vacuumed from the bottom. Soil temperature was monitored by 10 thermocouples and steaming was stopped when 5 of the thermocouples had reached the target temperature. The basket was then removed from the steaming container after 3 min. Plant materials were taken out and planted in pots. Buds sprouting was followed for 8 weeks. Non-steamed plant materials were used as controls. Results showed 100% rhizome death at soil temperatures of ≥70 and 99 °C in the first and second experiments, respectively. Shoot clumps death was obtained at ≥90 °C in both experiments. These results showed that steaming at 99 °C for 3 min can guarantee control of Bohemian knotweed in infested soils supporting the steam treatment as a potential method of disinfecting soil against invasive species. However, depending on the intended re-use of the soil, further studies are needed on the effect of potential negative impacts of high temperatures on the soil quality.
Abstract
Harvest weed seed control takes advantage of seed retention at maturity by collecting weed seeds as they pass through the harvester. We assessed the seed production and shedding pattern of common weed species in two wheat and two oat fields in Denmark. The aim was to evaluate the possibility of harvesting retained seeds on weeds at crop harvest by a combine harvester based on estimation of weeds seed retention. Before flowering, ten plants of each weed species were selected and surrounded by a seed trap comprising of a porous net. When the plants started shedding seeds, the seeds were collected from the traps and counted weekly until crop harvest. Just before crop harvest, the retained seeds on the plants were counted and the ratio of harvestable seeds and shed seeds during the growing season were determined. The seed production and shedding patterns varied between the species. In oat, Anagallis arvensis L., Capsella bursa-pastoris (L.) Medik., Chenopodium album L., Fallopia convolvulus (L.) Á. Löve, Geranium molle L., Persicaria maculosa Gray, Polygonum aviculare L., Silene noctiflora L., Sinapis arvensis L., Sonchus arvensis L., Spergula arvensis L., Stellaria media (L.) Vill.,Veronica persica Poir., and Viola arvensis Murray retained on average 61, 52, 67, 44, 58, 32, 59, 95, 67, 23, 45, 56, 51, and 33%, respectively, of their produced seeds at crop harvest. In wheat, Alopecurus myosuroides Huds. and Apera spica-venti (L.) P. Beauv. retained on average 34 and 33%, respectively, of their seeds at harvest. Silene noctiflora was classified as a good target for harvest weed seed control; A. myosuroides, A. spica-venti, C. bursa-pastoris, C. album, F. convolvulus, G. molle, P.maculosa, Sinapis arvensis, Sonchus arvensis, Spergula arvensis and V. arvensis were classified as intermediate targets; and A. arvensis, P. aviculare, S. media and V. persica were classified as poor targets. The research shows that there is a great potential to reduce the input of weed seeds to the soil seed bank by harvest weed seed control. Keywords: Harvest weed seed control; Soil seed bank ; Weed seed retention
Abstract
Eradication of alien invasive species in the soil with steam as an alternative to chemical fumigation may allow contaminated soil to be reused. We have investigated steam disinfestation of soil to combat invasive plant species in three experiments including different temperatures and exposure durations using a prototype stationary soil-steaming device. The experiments included effects on seed germination of bigleaf lupine (Lupinus polyphyllus Lindl.), ornamental jewelweed (Impatiens glandulifera Royle), and wild oat (Avena fatua L.; one population from Poland and one from Norway), as well as effects on sprouting rhizome fragments of Canada goldenrod (Solidago canadensis L.) and Bohemian knotweed (Reynoutria x bohemica Chrtek & Chrtková). In Experiment 1, we tested four different soil temperatures of 64, 75, 79, and 98 C with an exposure duration of 90 s. In Experiments 2 and 3, we tested exposure durations of 30, 90, and 180 s and 90, 180, and 540 s, respectively, at 98 C. Seed pretreatment of 14 d cooling for L. polyphyllus and I. glandulifera, no seed pretreatment and 12-h moistening for A. fatua populations, and 5- and 10-cm cutting size for R. x bohemica were applied. Our results showed germination/sprouting was inhibited at 75 C for I. glandulifera (for 90 s) and 98 C for the other species; however, longer exposure duration was needed for L. polyphyllus. While 30 s at 98 C was enough to kill A. fatua seeds and S. canadensis and R. x bohemica rhizome fragments, 180-s exposure duration was needed to kill L. polyphyllus seeds. The results showed promising control levels of invasive plant propagules in contaminated soil by steaming, supporting the steam treatment method as a potential way of disinfecting soil to prevent dispersal of invasive species.
Division of Biotechnology and Plant Health
Weeds vs. Crops: the winner of climate change
This project investigates the effects of climate change on competition between weeds and crops and will provide essential knowledge for developing adaptation strategies in the face of a changing climate.