HS Konsult AB

Örebro, Sweden

HS Konsult AB

Örebro, Sweden
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Anders J.,Precision Agriculture and Pedometrics | Katarzyna M.-S.,Precision Agriculture and Pedometrics | Gunnar B.,Plant Nutrition and Soil Biology | Ann-Charlotte W.,Precision Agriculture and Pedometrics | Ann-Charlotte W.,HS Konsult AB
European Journal of Plant Pathology | Year: 2016

Clubroot (Plasmodiophora brassicae) is a serious soil-borne disease in brassica crops world-wide. We report on a time series of soil samples from Swedish long-term fertility trials started in 1957, 1963 and 1966, which were analyzed for the amount of P. brassicae DNA. The crop rotations included a brassica crop every 4 or 6 years. All experimental sites with a 4-year rotation of oilseed rape, except one with calcium carbonate in the soil profile, showed high (>1000 fg DNA g−1 soil) levels of P. brassicae DNA after 9, 11 and 12 rotations. In contrast, detectable levels (>5 fg DNA g−1 soil) of P. brassicae were found only at one of five sites with a 6-year rotation of spring oilseed rape. In years with high levels of P. brassicae DNA, low yield was reported and a subsequent decline in P. brassicae DNA in soil was observed. Different NPK (nitrogen/phosphorus/potassium) fertiliser regimes resulted in similar P. brassicae DNA levels. The robustness and reliability of the method applied was verified by analyses of soil from individual plots compared with a mixture of plots and by repeated analyses of selected samples, which showed that P. brassicae DNA remained stable during dry storage. © 2016 The Author(s)

Wallenhammar A.-C.,Swedish University of Agricultural Sciences | Wallenhammar A.-C.,HS Konsult AB | Almquist C.,Swedish University of Agricultural Sciences | Almquist C.,Eurofins | And 2 more authors.
Plant Pathology | Year: 2012

A protocol using real-time polymerase chain reaction (PCR) for the direct detection and quantification of Plasmodiophora brassicae in soil samples was developed and used on naturally and artificially infested soil samples containing different concentrations of P. brassicae. Species-specific primers and a TaqMan fluorogenic probe were designed to amplify a small region of P. brassicae ribosomal DNA. Total genomic DNA was extracted and purified from soil samples using commercial kits. The amount of pathogen DNA was quantified using a standard curve generated by including reactions containing different amounts of a plasmid carrying the P. brassicae target sequence. The PCR assay was optimized to give high amplification efficiency and three to four copies of the target DNA sequence were detected. Regression analysis showed that the standard curve was linear over at least six orders of magnitude (R 2>0·99) and that the amplification efficiency was >92%. The detection limit in soil samples corresponded to 500 resting sporesg -1 soil. The intersample reproducibility was similar to, or higher than, that of assays for other pathogens quantified in soil samples. Bait plants were used to validate the real-time PCR assay. The protocol developed was used to investigate the spatial distribution of P. brassicae DNA in different fields and a significant difference was found between in-field sampling points. The reproducibility of soil sampling was evaluated and showed no significant differences for samples with low levels of inoculum, whereas at higher levels differences occurred. Indicator kriging was used for mapping the probability of detecting P. brassicae within a 2-ha area of a field. A threshold level of 5fg plasmid DNAg -1 soil, corresponding to approximately 3×10 3P. brassicae resting sporesg -1 soil, is suggested for growing resistant cultivars. The results provide a robust and reliable technique for predicting the risk of disease development and for assessing the distribution of disease within fields. © 2011 The Authors. Plant Pathology © 2011 BSPP.

Javed M.T.,University of Stockholm | Stoltz E.,HS Konsult AB | Lindberg S.,University of Stockholm | Greger M.,Hedmark University College
Environmental Science and Pollution Research | Year: 2013

The presence of Eriophorum angustifolium in mine tailings of pyrite maintains a neutral pH, despite weathering, thus lowering the release of toxic elements into acid mine drainage water. We investigated if the presence of slightly elevated levels of free toxic elements triggers the plant rhizosphere to change the pH towards neutral by increasing organic acid contents. Plants were treated with a combination of As, Pb, Cu, Cd, and Zn at different concentrations in nutrient medium and in soil in a rhizobox-like system for 48-120 h. The pH and organic acids were detected in the mucilage dissolved from root surface, reflecting the rhizospheric solution. Also the pH of root-cell apoplasm was investigated. Both apoplasmic and mucilage pH increased and the concentrations of organic acids enhanced in the mucilage with slightly elevated levels of toxic elements. When organic acids concentration was high, also the pH was high. Thus, efflux of organic acids from the roots of E. angustifolium may induce rhizosphere basification. © 2012 Springer-Verlag Berlin Heidelberg.

Almquist C.,Eurofins | Almquist C.,Swedish University of Agricultural Sciences | Wallenhammar A.-C.,Swedish University of Agricultural Sciences | Wallenhammar A.-C.,HS Konsult AB
Plant Pathology | Year: 2015

Sclerotinia stem rot of spring oilseed rape (Brassica napus) is caused by Sclerotinia sclerotiorum. In Sweden, the disease leads to severe crop damage that varies from year to year. A real-time PCR assay was developed and used to determine the incidence of S. sclerotiorum DNA on petals and leaves of spring oilseed rape as well as in air samples, with the aim of finding tools to improve precision in disease risk assessment. Five field experiments were conducted from 2008 to 2010 to detect and study pathogen development. Assessments of stem rot showed significant differences between experimental sites. The real-time PCR assay proved fast and sensitive and the relationship between percentage of infected petals determined using a conventional agar test and the PCR assay was linear (R2> 0·76). There were significant differences in S. sclerotiorum incidence at different stages of flowering. The incidence of S. sclerotiorum DNA on the leaves varied (0-100%), with significantly higher incidence on leaves at lower levels. In one field experiment, S. sclerotiorum DNA was not detected on petals during flowering, whereas the pathogen was detected on leaves, with a corresponding stem rot incidence of 7%. The amount of S. sclerotiorum DNA in sampled air revealed that spore release did not coincide with flowering on that experimental site. Thus, using a real-time PCR assay to determine the incidence of S. sclerotiorum on oilseed rape leaves, rather than on petals, could potentially improve disease risk assessment. © 2014 British Society for Plant Pathology.

Stoltz E.,HS Konsult AB | Wallenhammar A.-C.,HS Konsult AB | Wallenhammar A.-C.,Swedish University of Agricultural Sciences
Field Crops Research | Year: 2014

Manganese (Mn) deficiency is commonly connected with soil properties, and application of Mn is frequently performed to winter barley (Hordeum vulgare L.) in fields with a history of deficiency. Since the availability of Mn also is affected by seasonal variations, there is a risk of excessive application in some seasons while the application is not sufficient in other seasons in such fields. The objective of this study was to investigate the effect of foliar application of Mn in autumn and early spring on barley winter hardiness, in combination with or without N application in autumn. We also evaluated a commercially available Mn-scanner as a tool to identify the need for Mn application. Two field experiments per growing season were performed in south Sweden in 2010-2011 and 2011-2012 in fields where Mn deficiency often occurs. Foliar applications of various Mn products were made once (in October) or twice (in October and in March the following year). A single dose of 0 or 30kgha-1 N was applied, as NNO3, in October. Barley leaves were collected and Mn status determined with the NN-Easy55 Mn-scanner. Yield was determined in the field experiments in 2011-2012. Our results showed that the requirement of Mn application varied between sites and seasons and was affected by N supply. Mn application increased the winter survival by 33% and the grain yield by 36% in the barley plants with the lowest Mn status in autumn. The risk of Mn deficiency increased when N (NO3N) was applied in autumn. In one of the harvested field experiments, yield was suppressed by N application in autumn and was recovered by Mn application. Repeated Mn applications might be required to increase winter survival and grain yield, especially when N has been applied in the autumn. To reach an optimal Mn application, tools such as the NN-Easy55 Mn-scanner can be used to monitor the Mn status of the plants. Thereby unnecessary application of Mn is prevented and sufficient amounts are applied during deficiency. © 2014 Elsevier B.V.

Stoltz E.,HS Konsult AB | Nadeau E.,Swedish University of Agricultural Sciences
Field Crops Research | Year: 2014

This study investigated the effects of intercropping organically grown maize and faba bean under Swedish conditions on yield, forage quality, soil mineral nitrogen (N) content after harvest and weed incidence. Experiments with maize and faba bean as a monocrop and intercrop were performed at three field sites, with various amounts of N (dairy slurry) applied. The land equivalent ratio (LER) was 1.10-1.21 in two of the three experiments. The mean crude protein concentration of the three experiments increased from 63gkg-1, in feed of monocropped maize, to 107gkg-1, in feed of maize intercropped with faba bean. Intercropping had lower N balances compared with monocropped maize and tended to reduce the content of mineral N in the soil after harvest by, on average, 10kgha-1. Weed incidence was slightly reduced by intercropping compared with monocropped maize. In conclusion, the results show that intercropping maize and faba bean in organic production can generate positive yield effects with LER>1. Furthermore, intercropping resulted in higher protein content and lower residual soil mineral N after harvest compared to monocropped maize. Intercropping can thus increase the sustainability of forage production by reducing the need for protein feed and the risk of N pollution. The positive effects of intercropping, i.e. increased yield and reduced soil residual N, were found in the fields with relatively high amount of available N, but not in a field with lower N availability. © 2014 Elsevier B.V.

PubMed | HS Konsult AB, Rural economics and Agricultural Society, Swedish Seed and Oilseed Growers and Swedish University of Agricultural Sciences
Type: Journal Article | Journal: Plants (Basel, Switzerland) | Year: 2016

Outbreaks of clubroot disease caused by the soil-borne obligate parasite Plasmodiophora brassicae are common in oilseed rape (OSR) in Sweden. A DNA-based soil testing service that identifies fields where P. brassicae poses a significant risk of clubroot infection is now commercially available. It was applied here in field surveys to monitor the prevalence of P. brassicae DNA in field soils intended for winter OSR production and winter OSR field experiments. In 2013 in Scania, prior to planting, P. brassicae DNA was detected in 60% of 45 fields on 10 of 18 farms. In 2014, P. brassicae DNA was detected in 44% of 59 fields in 14 of 36 farms, in the main winter OSR producing region in southern Sweden. P. brassicae was present indicative of a risk for >10% yield loss with susceptible cultivars (>1300 DNA copies g soil(-1)) in 47% and 44% of fields in 2013 and 2014 respectively. Furthermore, P. brassicae DNA was indicative of sites at risk of complete crop failure if susceptible cultivars were grown (>50 000 copies g(-1) soil) in 14% and 8% of fields in 2013 and 2014, respectively. A survey of all fields at Lanna research station in western Sweden showed that P. brassicae was spread throughout the farm, as only three of the fields (20%) showed infection levels below the detection limit for P.brassicae DNA, while the level was >50,000 DNA copies g(-1) soil in 20% of the fields. Soil-borne spread is of critical importance and soil scraped off footwear showed levels of up to 682 million spores g(-1) soil. Soil testing is an important tool for determining the presence of P. brassicae and providing an indication of potential yield loss, e.g., in advisory work on planning for a sustainable OSR crop rotation. This soil test is gaining acceptance as a tool that increases the likelihood of success in precision agriculture and in applied research conducted in commercial oilseed fields and at research stations. The present application highlights the importance of prevention of disease spread by cleaning of farm equipment, footwear, etc.

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