Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Relationships among the contact patch length and width, the tire deflection and the rolling resistance of a free-running wheel in a soil bin facility
Get PDFQualitative and quantitative analysis of contact patch length-rolling resistance, contact patch width-rolling resistance and tire deflection-rolling resistance at different wheel load and inflation pressure levels is presented. The experiments were planned in a randomized block design and were conducted in the controlled conditions provided by a soil bin environment utilizing a well-equipped single wheel-tester of Urmia University, Iran. The image processing technique was used for determination of the contact patch length and contact patch width. Analysis of covariance was used to evaluate the correlations. The highest values of contact length and width and tire deflection occurred at the highest wheel load and lowest tire inflation pressure. Contact patch width is a polynomial (order 2) function of wheel load while there is a linear relationship between tire contact length and wheel load as well as between tire deflection and wheel load. Correlations were developed for the evaluation of contact patch length-rolling resistance, contact patch width-rolling resistance and tire deflection-rolling resistance. It is concluded that the variables studied have a significant effect on rolling resistance
Growth, body characteristics and blood parameters of ostrich chickens receiving commercial probiotics
Get PDFThis study was undertaken to determine the effect of four commercial probiotics on growth, body characteristics and haematological parameters of ostrich chicks. A total of 25 ostrich chicks (937±68.1 g) were individually allocated and fed the experimental diet for six weeks (n=5 per treatment). Experimental diets consisted of a corn/soybean meal-based diet unsupplemented (T1: Control), and four diets supplemented with probiotics according to the recommendations of the manufacturer (T2: 0.04% Bioplus 2B; T3: 0.09% Primalac; T4: 0.1% Thepax; and T5: 0.03% Protexin). Feed intake (FI), body weight (BW) and seven body characteristics (e.g. height) were measured every week. Blood samples and other body characteristics were also taken in the last week. There was an interaction effect between diet and time on all the growth variables and body characteristics (p<0.05). Both the BW and the BW gain of the ostrich chicks were, in general, higher for those fed the diet T2 than those fed the control diet (0.42, 1.07, 0.99, 1.09, 2.51, and 1.66 kg BW gain vs 0.28, 0.41, 0.83, 0.94, 1.15, and 1.15 kg BW gain at 7, 14, 21, 28, 35, and 42 days respectively), while for those fed the other diets containing probiotics differences were only observed at 42 days (p<0.05). Consuming probiotics over an extended period influenced several of the haematological parameters differently compared to those fed the control diet (p<0.05). T2 and T3 increased the concentration of total cholesterol (157 and 210 mg/dL respectively), when compared to those fed the control diet (119 mg/dL), while total cholesterol was slightly reduced (p>0.05) for those fed the diet containing Thepax (T4, 79 mg/dL). In conclusion, the effects of commercial probiotics on growth performance, body characteristics and haematological parameters varied among probiotics
The competitive advantage of the Tunisian palm date sector in the Mediterranean region
Get PDFIn Tunisia, date-palm cultivation and production are of clear strategic importance in terms of economic, social and environmental development. However, the globalization of markets has had a huge impact on the traditional concept of the comparative advantage enjoyed by Tunisia in date exports, highlighting the necessary determinants for competitiveness in the international scenario. In fact, an analysis of the competitive advantage of the Tunisian date industry in the Mediterranean area and Iran over the last 20 years shows that Tunisia is still the main supplier of dates to the EU. The Deglet-Nour variety, in particular, puts Tunisia ahead of traditional competitors such as Algeria and Iran, with average of competitiveness indices as BIS 6405.99, DI 17.38, CMS 41.04 and TBI 99.50 are more stable than those countries during the studied period. But it is currently facing new competitors like Israel and re-exporting countries like France. New business strategies (conditioning, new non-chemical treatments, packing, opening new markets, new distribution channels) would be positive responses to tackle current market limitations, the emergence of new producers and restrictive EU policies
Short communication. The role of rabbit density and the diversity of weeds in the development of cover crops in olive groves
Get PDFCover crops are an effective means to reduce soil erosion and to provide food and shelter for wildlife. However, in areas of intensive farming, which are characterised by the scarcity of weed communities, wild herbivores may focus their grazing on cover crops, which could make their implementation difficult. In this work, we test whether rabbit grazing can prevent the growth of herbaceous cover crops in olive groves in Southern Spain in addition to assessing the role of rabbit abundance and diversity of weeds in the development of cover crops. This question has been addressed by sowing Bromus rubens between the rows of five olive groves in Cordoba province (Spain). We then monitored the surface covered by B. rubens, along with both diversity of weed communities and rabbit abundance. Two rabbit exclusion areas were also placed in each olive grove in order to assess the impact of rabbits on the development of cover crops. Our results showed that the surface occupied by B. rubens was considerably higher in the rabbit exclusion areas (mean 56.8 ± 5.65 %) than in those areas in which they could feed (mean 35.6 ± 4.32 %). The coverage occupied by cover crops was higher in areas with lower rabbit density, although this relationship was modulated by the weed diversity index, since in areas with the same rabbit abundance the coverage was higher in those with a richer weed community. These findings suggest that high rabbit abundances can prevent the development of herbaceous cover crops in olive groves, particularly in areas in which alternative food resources (measured as weed diversity) are scarce
Segmentation of foreground apple targets by fusing visual attention mechanism and growth rules of seed points
Get PDFAccurate segmentation of apple targets is one of the most important problems to be solved in the vision system of apple picking robots. This work aimed to solve the difficulties that background targets often bring to foreground targets segmentation, by fusing the visual attention mechanism and the growth rule of seed points. Background targets could be eliminated by extracting the ROI (region of interest) of apple targets; the ROI was roughly segmented on the HSV color space, and then each of the pixels was used as a seed growing point. The growth rule of the seed points was adopted to obtain the whole area of apple targets from seed growing points. The proposed method was tested with 20 images captured in a natural scene, including 54 foreground apple targets and approximately 84 background apple targets. Experimental results showed that the proposed method can remove background targets and focus on foreground targets, while the k-means algorithm and the chromatic aberration algorithm cannot. Additionally, its average segmentation error rate was 13.23%, which is 2.71% higher than that of the k-means algorithm and 2.95% lower than that of the chromatic aberration algorithm. In conclusion, the proposed method contributes to the vision system of apple-picking robots to locate foreground apple targets quickly and accurately under a natural scen
Beef animal welfare, attitudes and Willingness to Pay: A regional comparison across the Pyrenees
Get PDFAttitudes towards beef animal welfare (AW) and Willingness to Pay (WTP) for AW certification are investigated among consumers in two Spanish and two French regions located on both sides of the Pyrenees (n=1213). Attitudes were measured through a scale of 11 animal practices, on which, consumers report their degree of concern and trust on the supply chain compliance. Attitudes significantly differed across regions, especially with respect to those AW practices carried out by farmers, while trust lies behind concerns. Three segments based on individual consumer attitudes are defined by opposing those consumers who are more concerned and who trust more on the compliance with AW standards (n=264, 22%) to those less concerned and who are more uncertain about stakeholders´ compliance with AW rules (n=356, 29%). Consumer location, gender, age and education significantly differed across attitudinal clusters. Results from a contingent valuation survey show that WTP for certified animal friendly beef ranged between 20.6% and 22.6% over the average market price of standard beef, in Spain and France, respectively. Both, consumers’ socio-demographic characteristics and habits regarding beef meat purchasing and attitudes towards farmers influenced this WTP (the more consumers trust in farmers’ involvement in animal welfare, the highest is their WTP), while a negative overall attitude significantly reduced WTP
Assessment of greening and collective participation in the context of agri-environmental schemes: The case of Andalusian irrigated olive groves
Get PDFAgri-environmental schemes (AES) in irrigated olive groves (IOG) in southern Spain were assessed based on farmers’ preferences toward these schemes. A choice experiment was used in this ex-ante assessment, with the inclusion of some innovative elements, such as collective participation and ecological focus areas (EFA). The results showed that farmers’ mean willingness to accept (WTA) participation in collective rather than individual AES was €124.5/ha. Their mean WTA for an additional 1% of EFA was €64.6/ha, while regarding the use of other agri-environmental practices, they showed a WTA of €6.3/ha and €114.7/ha for an additional 1% in the use of cover crops (CC) in olive grove areas and restrictive management of CC, respectively. These estimates were strongly influenced by farmers’ expectations and socio-economic characteristics, as well as farm management. We obtained that farmers’ expectations of no farm takeover reduce WTA for collective participation, whereas agricultural training and having at least a secondary-school education reduce farmers’ WTA for EFA and restrictive management of the CC, respectively. Conversely, harvesting ground olives increased farmers’ WTA for a high proportion of the area under CC. The analysis of the AES scenarios showed moderately high estimates of total WTA (€101-349/ha), especially when collective participation is required (€225-474/ha). The results supported the argument that there are efficient ways to encourage public goods provision, overcoming trade-offs with private goods provision by identifying the type of joint production
A bottom-up model to describe consumers’ preferences towards late season peaches
Get PDFPeaches are consumed in Mediterranean countries since ancient times. Nowadays there are few areas in Europe that produce peaches with Protected Designation of Origin (PDO), and the Calanda area is one of them. The aim of this work is to describe consumers’ preferences towards late season PDO Calanda peaches in the city of Zaragoza, Spain, by a bottom-up model. The bottom-up model proves greater amount of information than top-down models. In this approach it is estimated one utility function per consumer. Thus, it is not necessary to make assumptions about preference distributions and correlations across respondents. It was observed that preference distributions were neither normal nor independently distributed. If those preferences were estimated by top-down models, conclusions would be biased. This paper also explores a new way to describe preferences through individual utility functions. Results show that the largest behavioural group gathered origin sensitive consumers. Their utility increased if the peaches were produced in the Calanda area and, especially, when peaches had the PDO Calanda brand. In sequence, the second most valuable attribute for consumers was the price. Peach size and packaging were not so important on purchase choice decision. Nevertheless, it is advisable to avoid trading smallest size peaches (weighting around 160 g/fruit). Traders also have to be careful by using active packaging. It was found that a group of consumers disliked this kind of product, probably, because they perceived it as less natural
Comparing hypothetical versus non-hypothetical methods for measuring willingness to pay in a food context
Get PDFChoosing a valid procedure to measure willingness to pay (WTP) is crucial for designating optimum price policies or for evaluating the demand for new products. This study compares two methods for obtaining WTP in a food context: a random nth price auction and an open-ended contingent valuation (CV) question. Participants were regular salad tomato buyers of Alicante and they were randomly assigned to one of the two treatments. The products about which they would show their WTP were traditional tomato varieties. Both treatments were divided into three stages: in the first stage the only available information was a reference price for the tomatoes. In stages 2 and 3 we revealed the local origin and the organic grown of the tomatoes respectively. Our results show that in the auction the percentage of participants willing to pay the same or more than the reference price was between 20 and 30%. In the CV method this percentage was between 40 and 65%. The mean WTP in the auction, considering the whole of the individuals, was situated between 1.90 and 2.13 €/kg. These same results obtained through the CV were situated between 2.54 and 3.21 €/kg. The results confirmed the findings of previous papers in which the hypothetical bias of CV was clarified because it yields higher values for WTP than the auction, especially when referring to the number of individuals willing to pay more. Additionally, hedonic price models were estimated for the prices obtained by both methods with the result that in all the models, WTP was directly related to the price paid for the latest purchase of tomatoes