Soil microbiological attributes under summer/winter crops rotation in a no-tillage system

Knowledge of the effect of a multiple combination of summer/winter crop rotation on the microbiological properties of soil would allow a more adequate response to its use. This study aimed to evaluate the effect of the rotation of three summer crops (continuous soybean, continuous maize and soybean/maize rotation) in combination with seven winter crops (maize, sunflower, oilseed radish, millet, pigeon pea, sorghum and sunn hemp) on the microbiological properties of the soil. A soybean/maize (SM) rotation had a greater influence on microbial biomass than continuous maize (MM) and continuous soybean (SS). Urease and phosphatase activities were not affected by the crop rotation. Dehydrogenase activity was higher in continuous crops (MM and SS) than in SM, whereas respiratory activity was higher in SM than in continuous crops. For the SM rotation, the main variables selected by principal components analysis were microbial biomass C, N and P, respiratory and phosphatase activities, and microbial quotient. Pigeon pea, sorghum and sunn hemp had a greater effect on soil properties than the other winter crops. In general, the degree of influence of the summer and winter crops on the microbiological soil properties can be ranked as follows: SM > MM > SS, and millet > sorghum > sunn hemp > radish > pigeon pea > maize, respectively.     

Qualitative modifications of humic acid-like and core-humic acid-like during high-rate composting of pig faeces amended with wheat straw

Humic acid-like (HA-like) and core-humic acid-like (core-HA-like) were characterized during the high-rate composting process by CP-MAS ¹³C NMR, pyrolysis-gas chromatography (GC)/mass spectrometry (MS), and elemental analysis. Results obtained indicated that humification proceeded through a relative concentration of aromatic fractions due to the faster degradation of the O-alkyl and alkyl fractions. Core-HA-like, after purification of the parent material, showed a large reduction of the O-alkyl fraction in terms of HA-like. We concluded that HA-like consisted of refractory organic molecules, such as lignin and biopolymers, which formed a stable structure (core-HA-like) coated with degradable material associated with the core by weak physical association, ether or ester bounds.     

A universal microarray detection method for identification of multiple Phytophthora spp. using padlock probes

The genus Phytophthora consists of many species that cause important diseases in ornamental, agronomic, and forest ecosystems worldwide. Molecular methods have been developed for detection and identification of one or several species of Phytophthora in single or multiplex reactions. In this article, we describe a padlock probe (PLP)-based multiplex method of detection and identification for many Phytophthora spp. simultaneously. A generic TaqMan polymerase chain reaction assay, which detects all known Phytophthora spp., is conducted first, followed by a species-specific PLP ligation. A 96-well-based microarray platform with colorimetric readout is used to detect and identify the different Phytophthora spp. PLPs are long oligonucleotides containing target complementary sequence regions at both their 5' and 3' ends which can be ligated on the target into a circular molecule. The ligation is point mutation specific; therefore, closely related sequences can be differentiated. This circular molecule can then be detected on a microarray. We developed 23 PLPs to economically important Phytophthora spp. based upon internal transcribed spacer-1 sequence differences between individual Phytophthora spp. Tests on genomic DNA of many Phytophthora isolates and DNA from environmental samples showed the specificity and utility of PLPs for Phytophthora diagnostics.     

Immunohistochemical evaluation of MMP-2 and TIMP-2 in canine mammary tumours: a survival study

Canine mammary tumours (CMTs) are a very heterogeneous group of neoplasms with variable prognosis. Their aggressiveness is mainly due to their ability to invade locally and to metastasize. The degradation of extracellular matrix components is an important determinant of the invasive phenotype. The aims of this study were to analyse by immunohistochemistry and double immunofluorescence the expression of metalloproteinase 2 (MMP-2) and tissue inhibitor of metalloproteinase 2 (TIMP-2) in eight normal canine mammary glands and 118 CMTs (24 benign, 94 malignant) and to investigate relationships with metastatic disease and survival.MMP-2 and TIMP-2 expression was higher in malignant tumours than in normal canine mammary tissue and benign tumours. The main difference between benign and malignant CMTs was the pattern of expression of both molecules: benign tumours presented TIMP-2 and MMP-2 immunoreactivity in the myoepithelial cells lining the basement membrane of tubuloalveolar structures, while malignant tumours showed mainly diffuse expression in neoplastic cells. In malignant tumours, increased TIMP-2 expression was significantly associated with the development of distant metastases, lower overall survival and lower disease-free survival. MMP-2 expression was not significantly associated to any of these parameters. These results suggest that the immunohistochemical expression of TIMP-2 is a useful prognostic factor in CMTs.     

Assessing the uncertainty of estimated annual totals of net ecosystem productivity: A practical approach applied to a mid latitude temperate pine forest

Values for annual NEP of micrometeorological tower sites are usually published without an estimate of associated uncertainties. Few authors quantify total uncertainty of annual NEP. Moreover, different methods to assess total uncertainty are applied, usually addressing only one aspect of the uncertainty. This paper presents a robust and easy to apply method to quantify uncertainty of annual totals of Net Ecosystem Productivity (NEP), related to multiple factors involved therein. The method was applied to NEP observations for a Scots pine forest (Loobos) in the Netherlands. Total uncertainty of annual NEP for the Loobos site was on average ±32 g C m⁻² a⁻¹ (±8% of NEP), which is a quarter of the standard deviation of annual NEP (127 g C m⁻² a⁻¹).     

Development of qPCR assays to monitor the ability of <Emphasis Type="Italic">Gliocladium catenulatum</Emphasis> J1446 to reduce the cereal pathogen <Emphasis Type="Italic">Fusarium graminearum</Emphasis> inoculum in soils

A qPCR approach was developed to specifically monitor in soils Fusarium graminearum, the main agent responsible for Fusarium Head Blight, and the biocontrol agent Gliocladium catenulatum J1446 (Prestop®). For both fungi, the amplification efficacy of standard curves obtained by mixing pure fungal DNA and soil background DNA was high (qPCR efficacy>96% with R²?>?0.97) with a linear range from 10^?3 ng to 10 ng/μL. Our qPCR method allowed quantifying down to 1 μg of F. graminearum and G. catenulatum J1446 mycelium per g of soil. The strong correlation observed between fungal biomass and quantified DNA (R²?=?0.9927 and 0.9356 for F. graminearum and G. catenulatum J1446, respectively) supported the use of the primers to monitor both fungi in soils. Under our experimental conditions, the ability of Prestop® to reduce F. graminearum growth was significantly higher in autoclaved soil compared to living soils, suggesting that there is an antagonistic effect of the soil microbial communities. In contrast, G. catenulatum J1446 growth was mostly not affected by the presence of F. graminearum and was able to persist in both autoclaved and living soils after 15 days of incubation. These results indicate that our qPCR approach may be used to assess the success of soil colonization by a biocontrol agent and its control efficacy by monitoring the dynamics of the BCA and the targeted pathogen in soil.     

Biological and abiotic factors influencing the settlement and survival of Salicornia dolichostachya in the intertidal pioneer zone

During the last two decades a decrease of salt marsh area of at least 6% was found along the mainland coast of the Dutch Wadden Sea. However, it was not clear what determined the seaward boundary of the pioneer vegetation in this area. In the period 1993–1995, abiotic and biological variables were monitored along a transect from the mudflat to the low salt marsh in two sites, the Negenboerenpolder and the Noordpolder. At the Negenboerenpolder site the pioneer zone extended further from the dike and had a dense cover with vegetation when compared to the Noordpolder site. The observed difference in extension of the pioneer zone could not be attributed to differences in tidal frequency, sedimentation rate or nutrient availability. During the winter a dramatic loss in seed numbers was found at both sites. This loss decreased from mudflat to low marsh. The mud/sand ratio, on the other hand, increased from mudflat to low marsh and was higher in the Negenboerenpolder. The shear strength of the top soil layer measured with an insitu erosion flume was correlated to the mud/sand ratio and increased with an increasing mud content of the soil. The strength of the soil seems to be the key factor for the settlement and survival of Salicornia dolichostachya in the pioneer zone.     

The effects of the dark house system on growth,performance and meat quality of broiler chicken

Meat production with minimum animal suffering is a humanitarian concern. Thus, the objective of this work was to observe the performance of Cobb broiler chickens from 7 to 46 days of age when raised under different installations: dark house system (DHS), conventional yellow system (CYC) and conventional blue system (CBC). The feed conversion ratio for the birds raised on the DHS was 3.8% and 2.7% lower than those for the CYC and CBC systems, respectively. Compared with the CYC and CBC systems, average daily gain under the DHS was 11.4% and 9.3% higher, respectively, and body weight at 46 days was 11.4% and 9.3% higher, respectively (P ≤ 0.05). The birds' welfare was assessed based on their stress by determining the amount of pale, soft and exudative (PSE) meat in the breast fillets. The CYC and CBC birds had 24.3% and 25.3% PSE meat, respectively, whereas the DHS birds had 37.0%. We concluded that the DHS has a greater potential to produce broiler chickens, with superior performance to conventional systems, despite the higher stress faced by the birds during the maneuvers just before slaughter.     

Eenige waarnemingen met betrekking tot eenzijdige graanbouw

Summary In the Wieringermeerpolder reclaimed about 1930, some cases of severe damage caused by the Oats Nematode (Heterodera avenae Filipjev) have been observed since 1943. In one of the cases mentioned (I) 8×cereals have been grown in 13 years, viz. 3×oats, 3×wheat, 1×barley and 1×rye. In another case (II) 8×cereals occurred in 12 years, viz. 3×oats, 3×wheat and 2×barley. It is obvious that this crop rotation promotes the occurrence of the Oats Nematode. A crop rotation with less cereals is recommended.

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Voorlichtingsdienst in de Wieringermeer