Oilseed Rape Cultivation Research Articles

Spring Camelina sativa – Perspective cultivation as biofuel feedstock in Slovakia

Camelina [Camelina sativa (L.) Crantz], alternative low/medium-input oilseed crop, has variety of uses with biofuel production being at the forefront as its exploitation is primarily determined by greenhouse gas (GHG) emissions from feedstock production. The primary aim of the paper was to examine the possibilities of sustainable conventional and temporary intensification of prospective camelina cultivation as a biofuel raw material. Because camelina is still not commercially grown in Slovakia, oil flax yields and environmental demands were used as benchmark. Within conventional intensification, greenhouse gas emissions from its intended cultivation were compared with real emissions from oilseed rape cultivation. Inputs (especially N-fertilizers) and oilseed yields were investigated as two factors which significantly affected the amount of emissions from cultivation. Almost all of assumed camelina yields and nutrient rates combinations achieved lower total emissions compared with oilseed rape. This was mainly due to lower values from N2O emissions category and emissions from fertilizers category which accounted for a major share of emissions from cultivation. It can be concluded, that camelina could be suitable raw material for biofuel production. The set-aside land (fields) in Slovakia, which accounted for more than 40,000 ha, creates a potential space for a temporal intensification of camelina cultivation.

EVALUATION OF DOWNY MILDEW (HYALOPERONOSPORA BRASSICAE) INFECTION SEVERITY ON DIFFERENT CRUCIFEROUS OILSEED CROPS

Diseases constitute an important economic problem in oilseed rape (Brassica napus) cultivation. Although downy mildew has been counted so far as a minor disease, under intensive cultivation system and short rotation interval, the impact of diseases could increase in the future, especially under predicted more humid northern climatic conditions. This research study is the first report about the severity of downy mildew infection on cruciferous crops in Estonia. During two years (2010 − 2011), downy mildew infection severity was assessed in six different cruciferous crops (B. napus, B. juncea, B. nigra, Sinapis alba, Raphanus sativus, Eruca sativa) in field trials located in Eerika, Tartu County, Estonia. On both study years, four disease assessments were done. Downy mildew infection started a week earlier in 2010, but the overall disease pressure was lower compared to 2011. Based on our field trial results, S. alba, E. sativa and R. sativus plants were significantly more resistant to downy mildew compared to other tested crops. Furthermore, in 2010 downy mildew symptoms were not recorded on two cruciferous species E. sativa and R. sativus. Brassica nigra and B. napus plants were the most susceptible to downy mildew, with especially severe infection in 2011. Based on our two years data, downy mildew can damage foliage on spring oilseed rape (B. napus) and black mustard (B. nigra) in a notable extent. We conclude that downy mildew is an important pathogen, which should be monitored on different oilseed cruciferous crops in Estonia.

Antifungal effects of 3-(2-pyridyl)methyl-2-(4-chlorphenyl) iminothiazolidine against Sclerotinia sclerotiorum.

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum threatens oilseed rape cultivation, and the emergence of fungicide-resistant strains has led to control failures worldwide. Identifying novel chemical alternatives with different modes of action and high antifungal activities is thus crucial. Herein we evaluated the antifungal effects of 3-(2-pyridyl)methyl-2-(4-chlorphenyl)imino- thiazolidine (PMAS) on S. sclerotiorum to determine its efficacy for SSR management. PMAS had an inhibitory effect on mycelial growth; the EC50 values were 17.83 and 21.15 μg mL-1 for the carbendazim-susceptible strain Ss01 and carbendazim-resistant strain Hm25, respectively. PMAS treatment changed the color of inhibited mycelia to green, and the hyphae were sustained in the undifferentiated stage. Cysteine supplementation made this green color disappear, whereas methionine enhanced the color. Moreover, PMAS treatment markedly inhibited oxalic acid biogenesis, increased free thiol content in mycelia, and weakened the activities of oxaloacetase and malate dehydrogenase, but had little effect on the activity of glyoxylate dehydrogenase. Cysteine could reverse the inhibitory effects of PMAS on mycelial morphogenesis and biochemical constituents, except thiol production. In the pot-culture experiment, PMAS showed a good protective effect, with the control efficacy being >91% on SSR. PMAS appears to be an effective fungicide for SSR management. © 2020 Society of Chemical Industry.

Nitrous oxide emissions from oilseed rape cultivation were unaffected by flash pyrolysis biochar of different type, rate and field ageing

Nitrous oxide (N2O) emission from winter oilseed rape (WOSR) cultivation may compromise the sustainability of oilseed rape biodiesel. Typically, greenhouse gas budgets of WOSR cultivation assume an N2O emission factor (EF) of 1% of the N added in fertilizer and crop residues. Management options to reduce direct soil emissions of N2O include the application of biochar, but efficacy and mechanisms of N2O suppression are elusive. We measured N2O emissions in a WOSR field trial on a sandy loam soil in Denmark over 402 days in 2017–2018, comparing biochar applications from two feedstocks (wheat straw and pig manure fibers), two application rates (1.5 and 15 Mg ha−1) and field ageing of up to three years. Further, a controlled incubation experiment was performed to examine the effect of biochar dose and ageing on N2O production and consumption by denitrification. Biochar treatments had no significant effects on cumulative N2O emissions (1.71–2.78 kg N ha−1 yr−1). Likewise, no significant effects were found on crop yield, yield-scaled N2O emission, soil mineral N content, gravimetric soil moisture or pH. The fertilizer induced EF was 0.51% which is well below the IPCC Tier 1 EF of 1%. High doses of fresh, but not field-aged biochar suppressed N2O production under anoxic conditions ex situ, suggesting that biochar with sufficient liming capacity could mitigate N2O emissions from denitrification also under field conditions. Yet, rates of up to 15 Mg ha−1 flash pyrolysis biochar in the current in situ study, which comprised a pronounced summer drought, showed no significant N2O mitigation. This highlights the need for selecting dedicated biochars and doses and test them in multi-year studies to conclude on their N2O mitigating effect. Yet, in relation to sustainability of WOSR cultivation for biodiesel, the current study suggests that C sequestration by biochar is not compromised by increased N2O emissions.

Comparison of technical and systems-based approaches to managing pesticide contamination in surface water catchments

Diffuse pollution of surface waters by herbicides remains a problem despite 25 years of research into mitigation approaches. This study adopts the grassweed herbicide propyzamide as a focus to compare the efficacy of technical, field-scale, interventions with systems-based cropping solutions in a 900 ha headwater catchment on heavy clay soils. Catchment monitoring was combined with modelling of land management options using SWAT, and semi-structured discussions with farmers. Vegetated buffers are the main mitigation in the catchment at present, and these are estimated to be halving propyzamide concentrations in the headwater stream. Increasing vegetated buffers to 20 m width around all water courses would be the most effective technical intervention. Collaboration between farmers to ensure differentiated application timings would be ineffective without precise forecasting to avoid application soon before storm events. Downstream pesticide limits could only be met by restricting the area of land treated with propyzamide, requiring a switch away from oilseed rape cultivation. This restriction was not acceptable to farmers who noted the lack of enablers for coordination between landowners and the need for pesticide targets that are specific to headwater catchments.

Food, Feed and Environmental Risk Assessment of Glufosinatetolerant Genetically Modified Oilseed Rape T45 for Food and Feed Uses, Import and Processing Under Regulation (EC) No 1829/2003 (Application EFSA/GMO/UK/2005/25)

Food, Feed and Environmental Risk Assessment of Glufosinatetolerant Genetically Modified Oilseed Rape T45 for Food and Feed Uses, Import and Processing Under Regulation (EC) No 1829/2003 (Application EFSA/GMO/UK/2005/25)

Increasing yield, quality and profitability of winter oilseed rape (Brassica napus) under combinations of nutrient levels in fertiliser and planting density

Oilseed rape (Brassica napus L.) is a crucial source of edible oil and livestock feeding, and is a promising biofuel crop. The increasing demand for oilseed rape requires strategies to increase yield while retaining quality. Field experiments were performed in southern China to evaluate the impacts of fertiliser level and planting density on dry matter accumulation, seed oil and protein content (%) and yield (per ha), oil quality, and the profitability of oilseed rape. Fertiliser treatments contained nitrogen (N), phosphorus (P), potassium (K), sulfur (S) and boron (B) at four increasing rates, compared with nil fertiliser, and there were six planting densities (range 7.5–45 × 104 plants ha–1). Dry matter accumulation significantly (P < 0.05) increased in response to increasing plant population and fertiliser level, whereas harvest index decreased, suggesting that increasing the production of oilseed rape is limited to improvement of population quality. Seed oil and protein contents were significantly affected by fertiliser level rather than planting density. Increasing the fertiliser rate increased seed protein content, simultaneously slightly decreasing oil content. Glucosinolate content of rapeseed slightly decreased with increasing fertiliser but erucic and oleic acid contents were not affected, indicating that increasing the fertiliser rate might not reduce oilseed rape quality. Manipulation of fertiliser level was more effective than altering planting density for increasing seed oil and protein yields. Highest seed oil and protein yields resulted from the highest fertiliser application of 240 kg N, 52.4 kg P, 174.3 kg K, 15 kg S and 1.2 kg B ha–1, under a planting density of 22.5 × 104 plants ha–1. Maximum economic gain occurred with the two highest fertiliser levels, whereas planting density has no significant effect on profitability. A balanced application of NPKSB fertilisers should be employed with direct-sowing cultivation of oilseed rape, aimed at building a suitable population structure that balances plant population density and individual growth.

DMPP reduced nitrification, but not annual N2O emissions from mineral fertilizer applied to oilseed rape on a sandy loam soil

AbstractDirect field emissions of nitrous oxide (N2O) may determine whether biodiesel from oilseed rape (Brassica napus L.) fulfills the EU requirement of at least 50% reduction of greenhouse gas emissions as compared to fossil diesel. However, only few studies have documented fertilizer N emission factors (EF) and mitigation options for N2O emissions from oilseed rape cropping systems. We conducted a field experiment with three N levels (0, 171, and 217 kg/ha), where the N fertilizer was applied as ammonium sulfate nitrate with or without the nitrification inhibitor 3,4‐dimethylpyrazole phosphate (DMPP). N2O fluxes were measured using static chambers technique and soil samples were analyzed for water and mineral N content during a monitoring period of 368 days. The DMPP treatments showed a significantly increased level of ammonium () for up to 18 weeks after spring fertilization as compared to the treatments without DMPP. However, this difference did not result in a corresponding decrease in soil content, and no differences in cumulative N2O emissions were found between any fertilized treatments with or without DMPP (mean, 1.26 kg N2O‐N ha−1 year−1). More field experiments are needed to clarify whether DMPP‐coated mineral fertilizers could mitigate N2O emissions under different weather conditions, for example, under conditions where fertilization events concurred with rainfall events increasing water‐filled pore space to the assumed 60% threshold for denitrification. Emission factors for mineral N fertilizer were 0.28%–0.36% with a mean of 0.32% across the fertilized treatments. These data concur with recent European studies suggesting that the EF for mineral N fertilizers in oilseed rape cropping systems may typically be lower than the default IPCC value of 1%. Further studies are needed to consolidate an EF for oilseed rape under temperate conditions, which will be determining for the sustainability of Northern European oilseed rape cultivation for biodiesel.

Evaluation of the Effectiveness of Pod Sealants in Increasing Pod Shattering Resistance in Oilseed Rape (Brassica napus L.)

Shattering of pods of oilseed rape (Brassica napus L.) is a major cause of seed yield losses prior to and during harvesting. In order to reduce shattering, researchers have been engaged in the development of special preparations that are known as pod sealants (PS). Despite the fact that there are already developed and commercialized PSs that have only been effective on seed yield preservation under certain environmental conditions, there is still a need to create a more versatile and efficient PS. Currently, the most promising method of controlling pod shattering in oilseed rape is the application of our developed novel acrylic- and trisiloxane-based pod sealant (PS4). The effectiveness of PS4 and three commercial pod sealants (PS1, PS2, and PS3) was assessed in this comparative study. By spraying an oilseed rape crop with PS4, natural seed loss can be reduced by 20–70%, depending on the prevailing weather conditions, and loss of seeds during harvest can be reduced by more than three-fold compared with that by the control treatment. Thus, the overall results demonstrated that by applying a novel pod sealant (PS4) to oilseed rape crops 2 weeks before harvest can increase the net profit margin by €30–€150 ha−1. The life cycle assessment showed that during 2014–2016 oilseed rape cultivation, the largest effect on global warming emission (kg CO2 eq) reduction was experimental sealant PS4, i.e., approximately 17% compared to the control.

Potential for Seed Transmission of Verticillium longisporum in Oilseed Rape (Brassica napus).

Verticillium longisporum is a soilborne vascular fungal pathogen that has spread throughout the European oilseed rape cultivation area since the 1980s and was detected in canola fields in Canada in 2014. In a series of greenhouse and field inoculation experiments using V. longisporum-resistant and susceptible cultivars of winter and spring types of oilseed rape, the present study investigated the potential of V. longisporum dissemination by seeds of Brassica napus. Greenhouse inoculation studies with a DsRed-labeled isolate of V. longisporum confirmed the systemic growth of the pathogen from roots to seeds. Further monitoring of plant colonization in the greenhouse with a species-specific real-time polymerase chain reaction assay verified the pathogen growth from roots to stem bases, pods, and seeds in root-inoculated plants. The frequency of recovery of viable colonies of V. longisporum from seeds harvested from greenhouse-grown inoculated plants ranged from 0.08 to 13.3%. The frequency of seed transmission in the greenhouse differed in oilseed rape cultivars varying in susceptibility to V. longisporum. Subsequent studies on transmission of the disease into the offspring revealed that only 1.7 to 2.3% of plants showed disease symptoms as confirmed by the formation of microsclerotia in the stems. Results from field-grown plants differed from the greenhouse studies. The degree of seed transmission in the field was dependent on the crop type. Although only low concentrations of DNA of V. longisporum were detectable in seeds harvested from severely infected winter oilseed rape, significantly greater concentrations of fungal DNA were found in seeds of spring-type oilseed rape, at similar soil conditions and inoculum densities. Correspondingly, plating seeds that were harvested from infected plants on agar yielded viable V. longisporum colonies only from seeds of the spring-type but not of the winter-type plants. Lack of seed infection in the winter-type crop was confirmed in two seasons. Equally, none of the offspring grown from seeds from severely diseased winter oilseed rape plants developed symptoms of Verticillium stem striping. The results suggest that the rate of seed transmission of V. longisporum depends on the degree of plant colonization, which is significantly faster under greenhouse than field conditions and in a spring-sown crop compared with an autumn-sown oilseed rape crop. According to our studies, disease transmission by seeds from European winter oilseed rape production cannot be confirmed.

Optimal Nitrogen Fertilization Management of Seed-sowing Rapeseed in Yangtze River Basin of China.

For cultivation and high yield of oilseed rape (Brassica napus L.) in China, traditional seedling transplanting is replaced by seed-sowing but, better nitrogen management is crucial and not established yet. This study aimed to adapt N management to the seed-sowing method for the winter oilseed rape and to minimize the N fertilizer-derived pollution potential in the upper reaches of Yangtze River Basin. Three field experiments were conducted to check effect of different doses of N fertilizers, split doses of N and different types of N fertilizers for seed-sowing winter oilseed rape with high plant density in upper reaches of Yangtze River Basin in Sichuan province of China. In first experiment, among four doses (0, 90, 180 and 270 kg N ha-1) on average 3.54 t ha-1 was in 180 kg N ha-1 and 3.61 t ha-1 in 270 kg N ha-1 while cultivars dy6 and cn3 produced 3.23 and 3.29 t ha-1 which is significantly higher than zs11. There was no significant difference in N-use efficiency among three cultivars tested and second experiment showed no significant difference in seed yield with split N application. The third experiment compared the effects of different fertilizer types (urea, coated urea, 1:1 mixture of urea and coated urea and compound nitrogen fertilizer) on seed yield and get no significant difference in seed yield. This experiment proved that seed sowing method with higher nitrogen had high yield in the upper reaches of Yangtze River Basin in China, but higher N application may cause environment pollution. So, seed sowing method with nitrogen 180 kg N ha-1 was proved to be more effective.

Biochar potentially mitigates greenhouse gas emissions from cultivation of oilseed rape for biodiesel

Winter oilseed rape (WOSR) is the main crop for biodiesel in the EU, where legislation demands at least 50% savings in greenhouse gas (GHG) emissions as compared to fossil diesel. Thus industrial sectors search for optimized management systems to lower GHG emissions from oilseed rape cultivation. Recently, pyrolysis of biomass with subsequent soil amendment of biochar has shown potentials for GHG mitigation in terms of carbon (C) sequestration, avoidance of fossil based electricity, and mitigation of soil nitrous oxide (N2O) emissions. Here we analyzed three WOSR scenarios in terms of their global warming impact using a life cycle assessment approach. The first was a reference scenario with average Danish WOSR cultivation where straw residues were incorporated to the soil. The others were biochar scenarios in which the oilseed rape straw was pyrolysed to biochar at two process temperatures (400 and 800 °C) and returned to the field. The concept of avoided atmospheric CO2 load was applied for calculation of C sequestration factors for biochar, which resulted in larger mitigation effects than derived from calculations of just the remaining C in soil. In total, GHG emissions were reduced by 73 to 83% in the two biochar scenarios as compared to the reference scenario, mainly due to increased C sequestration. The climate benefits were higher for pyrolysis of oilseed rape straw at 800 than at 400 °C. The results demonstrated that biochar has a potential to improve the life cycle GHG emissions of oilseed rape biodiesel, and highlighted the importance of consolidated key assumptions, such as biochar stability in soil and the CO2 load of marginal grid electricity.

Sensitivity of oilseed rape (Brassica napus L.) to soil residues of imazethapyr herbicide

Imazethapyr is one of imidazolinone herbicides that may leave residual activity in the soil for extended periods causing injury and yield reduction of susceptible crops in rotation. An experiment was conducted in order to study the sensitivity of oilseed rape (Brassica napus L.) to imazethapyr soil residues. Experimental type was completely randomized design with three replications. Treatments included Imazethapyr simulated concentrations residuals in soil (0.002, 0.004, 0.008, 0.012, 0.02 and 0.04 mg. kg-1soil). Shoot and root biomass production was measured 30 days after emergence. Oilseed rape responses to imazethapyr residues was fitted with sigmoidal 3 and 4 parametric equations to the root and shoot biomass data as a function of the herbicide residue concentrations and was used to calculate the doses for 50% inhibition of root and shoot growth (ED50). Results showed that the oilseed rape shoot and root dry matter were significantly affected by increasing imazethapyr soil residue (p<0.01). This reduction in root dry matter was severe than shoot dry matter, where root ED50 (0.0019 mg.kg-1soil) was less than shoot dry matter (0.0025 mg.kg-1soil). Considering the high sensitivity of oilseed rape to imazatepara residues, attention is needed to provide oilseed rape cultivation in fields with a history of imazateaper application.

Unwrapping the Spontaneous Flora: On the Appropriation of Weed Labour

Abstract Part of the raw material accumulation for the medicinal plant industry in Romania is reliant on gathering plants from the so-called spontaneous flora. The imagery of medicinal plants played upon by medicinal plant product manufacturers is often abundant in visions of either wilderness or traditional peasant landscapes such as pastures. This article aims to present instead two different spaces where medicinal plants come from: wild pansy from within an oil seed rape cultivation, and elderflowers and nettles from the ruins of a former socialist orchard. These spaces of spontaneous flora highlight the process of capital’s appropriation or salvage of the ‘free’ reproductive labour (spontaneous growth) of weeds often at odds and against other capitalist processes. Moreover, salvaging or scrounging is done through the cheap labour of a family whose livelihood depends on work both inside and outside of this capitalist process. These places, therefore, highlight the tension between the spontaneous flora and scroungers on the ground and Nature with its ancestral peasants on the supermarket and nature shop shelves.

Genetic variation for vernalization requirement of winter oilseed rape

Global warming is currently enabling the expansion of winter oilseed rape cultivation to previously unsuitable regions. Nevertheless, extreme frost events may lead in some years to severe winter damage. On the other hand, early flowering winter oilseed rape cultivars are wanted because of increasingly warm temperatures in spring. An assumed correlation between winter hardiness and vernalization requirement therefore needs to be investigated. Analysing the genetic variation for vernalization requirement in a large set of genetically diverse winter oilseed rape genotypes revealed large and significant variation for this trait.

Potential impact of genetically modified Lepidoptera-resistant Brassica napus in biodiversity hotspots: Sicily as a theoretical model.

The general increase of the cultivation and trade of Bt transgenic plants resistant to Lepidoptera pests raises concerns regarding the conservation of animal and plant biodiversity. Demand for biofuels has increased the cultivation and importation of oilseed rape (Brassica napus L.), including transgenic lines. In environmental risk assessments (ERAs) for its potential future cultivation as well as for food and feed uses, the impact on wild Brassicaeae relatives and on non-target Lepidoptera should be assessed. Here we consider the potential exposure of butterflies as results of possible cultivation or naturalization of spilled seed in Sicily (Italy). Diurnal Lepidoptera, which are pollinators, can be exposed directly to the insecticidal proteins as larvae (mainly of Pieridae) through the host and through the pollen that can deposit on other host plants. Adults can be exposed via pollen and nectar. The flight periods of butterflies were recorded, and they were found to overlap for about 90% of the flowering period of B. napus for the majority of the species. In addition, B. napus has a high potential to hybridise with endemic taxa belonging to the B. oleracea group. This could lead to an exposure of non-target Lepidoptera if introgression of the Bt gene into a wild population happens. A rank of the risk for butterflies and wild relatives of oilseed rape is given. We conclude that, in environmental risk assessments, attention should be paid to plant-insect interaction especially in a biodiversity hotspot such as Sicily.

The influence of chosen fungicides on the activity of aminopeptidases in winter oilseed rape during pods development

Cultivation of oilseed rape requires application of specific fungicides. Besides their protective role, they can potentially influence the expression and activity of crucial enzymes in the plant. Among the large number of enzymes expressed in plants, aminopeptidases play a key role in all crucial physiological processes during the whole life cycle (e.g. storage protein mobilization and thus supplying plant with needed amino acids, as well as plant aging, protection and defense responses). In the present paper, we evaluate for the first time, the influence of the treatment of winter oilseed rape with commercially available fungicides (Pictor 400 SC, Propulse 250 SE and Symetra 325 SC), on the activity of aminopeptidases expressed in each plant organ (flowers, leaves, stems and pods separately). Fungicides were applied once, at one of the three stages of oilseed rape development (BBCH 59–61, BBCH 63–65 and BBCH 67–69). The aminopeptidase activity was determined using six different amino acid p-nitroanilides as substrates. The results have shown, that in control plants, at the beginning of intensive pods development and seeds production, hydrophobic amino acids with bulky side chains (Phe, Leu) were preferentially hydrolysed. In control plants, the activity was ~3.5 times higher in stems and pods, compared to leaves. The treatment with all pesticides caused significant increase in aminopeptidases hydrolytic activity toward small amino acids Gly, Ala as well as proline, mostly in flowers and leaves. These amino acids are proven to be crucial in the mechanisms of delaying of plant aging, development of better resistance to stress and plant defense. It can be suggested, that studied fungicides enhance such mechanisms, by activating the expression of genes coding for aminopeptidases, which are active in hydrolysis of N-terminal amino acids such as Gly, Ala, Pro from storage peptides and proteins. Depending on fungicide, the major increase of aminopeptidase activity was observed after application at BBCH 67–69 (Pictor 400 SC and Symetra 325 SC) and BBCH 63–65 (Propulse 250 SE) stages of development. Our study revealed, that agrochemical treatment and time of application, influenced the expression and activity of aminopeptidases, even though they were not molecular targets of applied fungicides. Since aminopeptidases are widely distributed throughout all organisms and are crucial in many key physiological processes, it can be expected, that factors influencing their expression and activity in plants, can also influence these enzymes in other organisms, especially humans and other mammals.

Oilseed rape cultivation increases the microbial richness and diversity in soils contaminated with cadmium

PurposeThis investigation aimed to estimate and characterize the microbial diversity in soils with cadmium (Cd) at different concentrations and to evaluate whether Brassica napus can restore the soil microbial diversity.Materials and methodsWe conducted the pot experiment to analyze the composition of microbial communities in the soil contaminated with 0, 1, and 2 mg/kg Cd, as well as planted with oilseed rape. The bacterial and fungal communities were characterized via next-generation sequencing based on 16S and 18S rRNA gene fragments pyrosequencing, respectively.Results and discussionThe results show that cadmium contamination decreased both the microbial richness and diversity in the soil, while the cultivation of oilseed rape increased the richness and diversity. In bacteria, Proteobacteria was the most abundant phylum in all the samples accounting for 39.62 to 46.14%, followed by Bacteroidetes, Actinobacteria, and Chloroflexi. These phyla collectively comprised more than 70% of all phyla. Ascomycota was the most abundant phylum in all samples in fungi (89.65 to 96.00%), and it was the only phylum whose abundance was increased with the rise of Cd concentration.ConclusionsMicrobial richness and diversity were affected by the combined action of Cd and B. napus. Cd contamination decreased the microbial richness and diversity, while cropping with oilseed rape increased the microbial richness and diversity, which alleviated the deleterious effect of the Cd pollution in soils. These reflected that oilseed rape played a positive role in maintaining species diversity of microorganism from the side.

Breeding for insect resistance in oilseed rape: Challenges, current knowledge and perspectives

AbstractDealing with insect pests is one of the biggest challenges facing the cultivation of oilseed rape (Brassica napus, OSR). Insect pests are usually controlled using insecticides, but the increasing occurrence of insecticide‐resistant populations and the socio‐economic context argue against the sole use of these substances. Plant resistance is a classical and proven alternative crop protection strategy that is the basic tool of integrated pest management. However, no insect‐resistant OSR cultivar is currently available on the market. Here, I review some of the constraints that make phenotyping for insect resistance particularly challenging with OSR and give perspectives to develop this resistance. Some studies have proved that breeding OSR for insect resistance could be achieved, and three strategies have been considered: introducing resistance transgenes into the OSR genome, exploiting natural variation in resistance already present in B. napus and introgressing resistance from other brassicaceous species. The white mustard, Sinapis alba, seems a particularly promising source of resistance against most of the OSR insect pests.

Nitrous oxide emissions from winter oilseed rape cultivation

Abstract Winter oilseed rape (Brassica napus L., WOSR) is the major oil crop cultivated in Europe. Rapeseed oil is predominantly used for production of biodiesel. The framework of the European Renewable Energy Directive requires that use of biofuels achieves GHG savings of at least 50% compared to use of fossil fuel starting in 2018. However, N2O field emissions are estimated using emission factors that are not specific for the crop and associated with strong uncertainty. N2O field emissions are controlled by N fertilization and dominate the GHG balance of WOSR cropping due to the high global warming potential of N2O. Thus, field experiments were conducted to increase the data basis and subsequently derive a new WOSR-specific emission factor. N2O emissions and crop yields were monitored for three years over a range of N fertilization intensities at five study sites representative of German WOSR production. N2O fluxes exhibited the typical high spatial and temporal variability in dependence on soil texture, weather and nitrogen availability. The annual N2O emissions ranged between 0.24 kg and 5.48 kg N2O-N ha−1 a−1. N fertilization increased N2O emissions, particularly with the highest N treatment (240 kg N ha−1). Oil yield increased up to a fertilizer amount of 120 kg N ha−1, higher N-doses increased grain yield but decreased oil concentrations in the seeds. Consequently oil yield remained constant at higher N fertilization. Since, yield-related emission also increased exponentially with N surpluses, there is potential for reduction of the N fertilizer rate, which offers perspectives for the mitigation of GHG emissions. Our measurements double the published data basis of annual N2O flux measurements in WOSR. Based on this extended dataset we modeled the relationship between N2O emissions and fertilizer N input using an exponential model. The corresponding new N2O emission factor was 0.6% of applied fertilizer N for a common N fertilizer amount under best management practice in WOSR production (200 kg N ha−1 a−1). This factor is substantially lower than the linear IPCC Tier 1 factor (EF1) of 1.0% and other models that have been proposed.