Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels

Simultaneous analysis of economic and environmental performance of horticultural crop production requires qualified assumptions on the effect of management options, and particularly of nitrogen (N) fertilisation, on the net returns of the farm. Dynamic soil-plant-environment simulation models for agro-ecosystems are frequently applied to predict crop yield, generally as dry matter per area, and the environmental impact of production. Economic analysis requires conversion of yields to fresh marketable weight, which is not easy to calculate for vegetables, since different species have different properties and special market requirements. Furthermore, the marketable part of many vegetables is dependent on N availability during growth, which may lead to complete crop failure under sub-optimal N supply in tightly calculated N fertiliser regimes or low-input systems. In this paper we present two methods for converting simulated total dry matter to marketable fresh matter yield for various vegetables and European growth conditions, taking into consideration the effect of N supply: (i) a regression based function for vegetables sold as bulk or bunching ware and (ii) a population approach for piecewise sold row crops. For both methods, to be used in the context of a dynamic simulation model, parameter values were compiled from a literature survey. Implemented in such a model, both algorithms were tested against experimental field data, yielding an Index of Agreement of 0.80 for the regression strategy and 0.90 for the population strategy. Furthermore, the population strategy was capable of reflecting rather well the effect of crop spacing on yield and the effect of N supply on product grading

Main viruses in sweet cherry plantations of Central-Western Spain

Sweet cherry trees (Prunus avium L.) are susceptible to a range of diseases, but there have been no studies to date about the viral infection of sweet cherry trees in Spain. To determine the phytosanitary status of Spanish sweet cherry plantations, the incidence and leaf symptoms induced by Prune dwarf (PDV), Prunus necrotic ringspot (PNRSV) and Apple chlorotic leaf spot (ACLSV) viruses were investigated during 2009. Young leaf samples were taken from 350 sweet cherry trees, corresponding to 17 cultivars, and were analysed by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). To associate the leaf symptoms with the virus, 50 mature leaves from each infected tree were visually inspected during the summer. The ELISA results revealed that 72 % of sweet cherry trees were infected by at least one of the viruses. PDV occurred in all sampled cultivars and presented the highest infection rate, followed by ACLSV and PNRSV. A high number of trees showed asymptomatic, in both single and mixed infections. The leaf symptoms associated with the viruses involved generalized chlorosis around the midvein (PDV), chlorotic and dark brown necrotic ringspots on both secondary veins and intervein regions (PNRSV), chlorotic and reddish necrotic ringspots (ACLSV) and generalized interveinal chlorosis (PDV-PNRSV)

The Relevance of Nationality and Industry for Stakeholder Salience: An Investigation Through Integrated Reports

The aim of this research is to investigate the web of business-stakeholder relationships emerging from first integrated reports. Drawn from the stakeholder salience theory, the analysis focuses on some factors that may cause specific stakeholders to be crucial for some organizations and their ability to create value over time. More precisely, findings highlight the importance of industry membership, while entities’ nationality seems not to be a differentiating element. This study contributes to the corporate disclosure literature by analyzing an emerging reporting tool, the integrated report, and demonstrating that the link between some business characteristics and stakeholder salience seems fundamental for the representation of the impact of corporate social and environmental responsibilities on the economic performance. From a practical point of view, the impact of industry membership on corporate disclosures encourages the drafting of differentiated reporting standards across sectors, in order to improve comparability, materiality, and reliability of information

Dependence of Anomalous Phosphorus Diffusion in Silicon on Depth Position of Defects Created by Ion Implantation

Transient enhanced diffusion of phosphorus in silicon has been investigated for implants below and above the threshold for a complete amorphization. Rapid thermal processes (electron beam) and conventional furnaces have been used for the annealing. In the case of implants below amorphization, a strong enhanced diffusion, proportional to the amount of damage produced, has been observed. The extent of the phenomenon is practically independent of the damage depth position. In contrast to this, the formation of extended defects at the original amorphous-crystalline interface makes the diffusivity strongly dependent on depth in the case of post-amorphized samples. No enhanced diffusion effect is observed if the dopant is confined in the amorphous layer, while a remarkable increase in the diffusivity is detected for the dopant located in the crystalline region beyond the amorphous-crystalline interface

THERMAL CONDUCTIVITY MEASUREMENTS OF IMPLANTED Si

On a mesuré la phase du signal photoacoustique pour du Si amorphe obtenu par implantation ionique et évaporé. La détermination de la conductivité thermique est obtenue par le modèle à deux couches.We have measured photoacoustic-signal phase of ion implanted and evaporated Si. The values of thermal conductivity of amorphous layers have been determined by a two layer theoretical model

Lattice strain and static disorder determination in Si/Si1-xGex/Si heterostructures by convergent beam electron diffraction

Lattice strain and static disorder present in Si1-xGex alloys forming Si/Si1-xGex/Si heterostructures with a Ge atomic fraction x equal to 0.1, 0.2, and 0.3, have been studied by convergent beam electron diffraction and large-angle convergent beam electron diffraction. These techniques have been used in order to perform structural analysis of the alloys with a spatial resolution comparable with the dimensions involved in Si/SiGe applications. Strain values along directions both perpendicular and parallel to the sample surface have been determined from a single high-order Laue zone deficiency lines pattern. The resulting relaxed alloy lattice constant has been found to depend on the Ge atomic fraction following a nearest-neighbor model alloy, where die Si-Si, Ge-Ge, and Si-Ge bond lengths combine themselves with a negligible dependence on the Ge atomic fraction. From lattice strain values, both the strain-induced bond bend in the plane of the interface, and the strain-induced bond stretch have been determined. Static disorder measurements, performed by comparing the integrated intensity of high-angle diffracted beams in the silicon substrate and in the SiGe layers, allow the determination of the atomic mean-square displacements produced by the presence in the same coordination shell of Si-Si, Ge-Ge, and Si-Ge atomic pairs with different bond lengths. The measured atomic displacements are greater than the ones predicted by both. the nearest-neighbor solution model (which only accounts for the different bond lengths, and not for both band trend and strain) and a relaxed alloys structure Monte Carlo simulation (which accounts for differences in bond lengths and bond bend, but neglects the effect of strain). The component of the atomic displacement related to the macroscopic strain has been determined as the difference between the experimental values and those computed by Monte Carlo code. A linear correlation between the strain-induced atomic displacement and the strain-induced bond bend in the plane of the interface has been found. [S0163-1829(99)04343-X]