29 research outputs found
Effect of Rapid or slow release nitrogen supply and cover crop/weed management on crop yield, pest incidence and fruit quality in intensive organic apple production
Apple is the commercially most important top fruit crop grown in the European Union.
In spring 2001 one-year-old trees of the apple variety ‘Ingrid Marie’ were established in an organic production system with 3.0 m between the tree rows. Each plot consisted of three semi-plots at planting distances 0.6m (5555 trees ha-1), 0.9 m (3333 trees ha –1) and 1.2 m (2777 trees ha-1). Tree growth, soil moisture, soil-, leaf- and branch analysis, diseases, fruit production, outer and inner fruit quality were measured.
The healthiest trees with the best coloured fruits were produced on trees grown in weed. But the yield was so low that production was not economical. A high production combined with trees less infected with fruit tree canker and with a satisfactory colouring was produced on trees grown in intensive production system of 5555 trees per ha with no nitrogen supply
Combined production of broilers and fruits
Combined production of broilers and fruit trees is a subject often discussed in organic fruit
production in Denmark. Very little research has been carried out on this type of production
system. In organic production in Denmark, nearly no pesticides are allowed, so the need
for alternative pest control is large. Apple sawfly (Hoplocampa testudinea) and pear midge
(Contarinia pyrivora) cause big crop losses in apples and pears respectively, in unsprayed
organic fruit production. Both insects infest fruitlets and cause these to drop prematurely
after which the pests pupate in the topsoil. In the present experiment a research orchard
with the varieties ‘Discovery’ and ‘Conference’ were used as outdoor area for broilers to
minimise the population of sawflies and pear midges, and to reduce the need for weeding
and manuring. The trees were kept unsprayed. Fruit yield and fruit quality were assessed
at harvest. White sticky traps were placed in the test area in order to measure the
occurrence of sawfly over time. The infestation of pear midge was investigated counting
the infested fruitlets in clusters on trees at the centre of the plots. The catch of apple
sawflies was reduced in the combined apple and broiler production, but no significant
effect on the yield or the fruit quality was seen. Experiences from on-farm research show
that combining fruit and egg-production is one way to reduce the problem with apple
sawfly, but poultry alone is not a sufficient way of controlling sawflies. The welfare and
health of the broilers were excellent under fruit trees
Phenolic compounds and disease resistance of 5 blackcurrant varieties in an organic growing system
The field resistance and the concentration of phenolic compounds of five black currant varieties grown under organic conditions were compared. Significant differences between varieties were seen for all of seven quantified hydroxycinnamic acid derivatives. The variety 'Intercontinental' clearly contained the highest level of hydroxycinnamic acid esters and at the same time was the most resistant variety. There seems to be a connection between the content of a caffeoyl-di-quinic acid ester and coumaryl-quinic acid ester and disease resistance under field conditions. The effect of four different growing conditions was much less evident. Analysis of the content of these phenolic acids might be a tool to help choosing the disease resistant varieties that are suitable for organic growing
Field efficacy of new compounds to replace copper for scab control in organic apple production
Efficacy of compounds was investigated in field experiments in Denmark and the Netherlands according to EPPO guidelines. Some Yucca extracts and potassium bicarbonate had an efficacy similar to sulphur on leaves. Addition of sulphur to Yucca 1 and to potassium bicarbonate increased the level of efficacy to that of copper. This confirms results from earlier years. Although a dose increase resulted in better efficacy, this was more prominent for Yucca1 than for potassium bicarbonate
Prevention and control of apple scab
Improved prevention and control of apple scab caused by Venturia inaequalis is aimed at without the use of copper containing products in the Repco-project. Substantial progress is made in selection of potential products against summer epidemics. A patent application is made for E73. New effective biocontrol agents are selected to reduce inoculum during winter. The product potassium bicarbonate has shown good efficacy and Repco contributes to the registration of this product in Europe. Earthworms tended to be stimulated to consume apple leaves treated with amino acids or beetpulp, especially when applied fresh under controlled environmental condi-tons
Perfluorooctane sulfonate concentrations in amniotic fluid, biomarkers of fetal Leydig cell function, and cryptorchidism and hypospadias in Danish boys (1980–1996)
Background: Exposure to perfluorooctane sulfonate (PFOS) may potentially disturb fetal Leydig cell hormone production and male genital development.
Objectives: We aimed to study the associations between levels of amniotic fluid PFOS, fetal steroid hormone, and insulin-like factor 3 (INSL3) and the prevalence of cryptorchidism and hypospadias.
Methods: Using the Danish National Patient Registry, we selected 270 cryptorchidism cases,75 hypospadias cases, and 300 controls with stored maternal amniotic fluid samples available in a Danish pregnancy-screening biobank (1980–1996). We used mass spectrometry to measure PFOS in amniotic fluid from 645 persons and steroid hormones in samples from 545 persons. INSL3 was measured by immunoassay from 475 persons. Associations between PFOS concentration in amniotic fluid, hormone levels, and genital malformations were assessed by confounder-adjusted linear and logistic regression.
Results: The highest tertile of PFOS exposure (> 1.4 ng/mL) in amniotic fluid was associated with a 40% (95% CI: –69, –11%) lower INSL3 level and an 18% (95% CI: 7, 29%) higher testosterone level compared with the lowest tertile (< 0.8 ng/mL). Amniotic fluid PFOS concentration was not associated with cryptorchidism or hypospadias.
Conclusions: Environmental PFOS exposure was associated with steroid hormone and INSL3 concentrations in amniotic fluid, but was not associated with cryptorchidism or hypospadias in our study population. Additional studies are needed to determine whether associations with fetal hormone levels may have long-term implications for reproductive health
Response theory for time-resolved second-harmonic generation and two-photon photoemission
A unified response theory for the time-resolved nonlinear light generation
and two-photon photoemission (2PPE) from metal surfaces is presented. The
theory allows to describe the dependence of the nonlinear optical response and
the photoelectron yield, respectively, on the time dependence of the exciting
light field. Quantum-mechanical interference effects affect the results
significantly. Contributions to 2PPE due to the optical nonlinearity of the
surface region are derived and shown to be relevant close to a plasmon
resonance. The interplay between pulse shape, relaxation times of excited
electrons, and band structure is analyzed directly in the time domain. While
our theory works for arbitrary pulse shapes, we mainly focus on the case of two
pulses of the same mean frequency. Difficulties in extracting relaxation rates
from pump-probe experiments are discussed, for example due to the effect of
detuning of intermediate states on the interference. The theory also allows to
determine the range of validity of the optical Bloch equations and of
semiclassical rate equations, respectively. Finally, we discuss how collective
plasma excitations affect the nonlinear optical response and 2PPE.Comment: 27 pages, including 11 figures, version as publishe
Intergrated production of black currants (Ribes nigrum) and sour cherries (Prunus cerasus)
Effects of urea on the formation of apothecia and winter conidia of Blumeriella jaapii (cherry leaf spot) and associated microfungi on overwintered cherry leaves
Preliminary results show rain roofs to have remarkable effect on diseases of apples
Abstract In the spring of 2012 narrow plastic covered roofs (2 m wide and 3 m tall) were erected over 6 x 8 trees in rows of Red Elstar and Rubens apples (planted 2009