Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Development of models to predict product deposition from coverage obtained on artificial collectors and their practical application
Get PDFModels to relate the observed coverage on artificial collectors used in field tests (water-sensitive paper, WSP) and in laboratory bioassays of citrus pests (pieces of polyvinyl chloride sheets, PVC) with product deposition are described. Different solutions of plant protection products commonly used for pest control in citrus were sprayed in a Potter Tower on PVC and WSP under the same controlled conditions. These experiments led to the formulation of different basic models to relate coverage and deposition depending on the products and collectors. The best fitting model was selected from among those that had highest coefficients of determination (R2) and lowest estimation error (RMSEP), and at the same time resulted in a normal distribution of residuals. Finally, coverage on pieces of PVC sheets was related with coverage obtained on WSP by different equations depending on the product being applied. Such equations can be used to link laboratory and field results in order to assess the quality of a spray application in citrus cultivation
Short communication. An association between the G/A single nucleotide polymorphism within intron II of VIP gene and milk performance traits in dairy cattle
No full textSingle nucleotide polymorphisms (SNPs), which are present in the encoding part of the genes responsible for important breeding functions, exert an influence on the cattle’s phenotype since their function is to regulate the genes expression. In this study a G/A single nucleotide polymorphism within intron II of the vasoactive intestinal peptide (VIP) gene was detected. The study covered a herd of 185 Jersey dairy cows from the Wielkopolska Province in Poland. All possible VIP/DraI genotypes determined by using two alleles (AA, AG, GG) were examined in the herd of cows under study. The AA genotype frequency was 0.48; AG 0.22, and GG 0.30. Allele A frequency was 0.592, whereas allele G was 0.408. Analyzed VIP/DraI gene polymorphism with respect to milk utility traits showed slight statistical differences in the percentage of fat and protein content in milk of the animals with different VIP/DraI genotypes. This study could have a significant influence on dairy cattle breeding programs in the future as improvements in genetic selection methods will continue to be important in milking management
Biological water contamination in some cattle production fields of Argentina subjected to runoff and erosion
Get PDFGrain production has displaced livestock to marginal lands in most of the productive regions in Argentina since 1990. In the fertile Rolling Pampa region, extensive cattle production has been concentrated in lowlands subjected to flooding, salt excess, erosion and sedimentation processes but also in some feedlots recently located in sloping arable lands prone to soil erosion. We studied the concentration of microbiological contamination indicators in runoff water and sediments accumulated in depressions along the tributary network from these lands devoted to cattle production. The aims of this work were: (i) to gather a reliable set of data from different monitoring periods and scales, (ii) to search for simple and sensible variables to be used as indicators for surface water quality advising purposes and (iii) to corroborate previous biological contamination conceptual models for this region. Concentration of pollution indicators in these ponds was related to mean stocking rates from nearby fields and proved to depend significantly on the accumulated water and sediments. Viable mesophiles and total coliforms were found mainly attached to large sediments rather than in the runoff water phase. Seasonal sampling showed that the time period between the last significant runoff event and each sampling date regarding enterococci proved to be a sensible variable for predicting contamination. Enterococci concentration tended to increase gradually until the next extraordinary runoff event washed away contaminants. The mentioned relationship may be useful for designing early warning surface water contamination programs regarding enterococci dynamics and other related microbial pollutants as well
Differential quality and technical/managerial advice relationships in Andalusian (Spain) olive oil protected designations of origin
Get PDFA relevant topic investigated in ‘Local Agro-Food Systems’ studies (LAFS) is the key role of collective action in the dissemination of innovations and knowledge aimed at the organization of quality on a local scale. The scope of this article deals with the methodological tools for typifying the relationships made, in LAFS hosting a Protected Designation of Origin (PDO), between the relational social capital and the differential quality of firms. The objective of this work is to categorize the agro-industrial firms into hierarchies for implementing rural development policies, with respect to their technical and managerial advice relationships and their score achieved in terms of product and process quality. The study takes into account the LAFS of “Estepa” and “Sierra de Segura”, Andalusia (S Spain), corresponding to two important olive oil PDOs. The methodological approach comprises, firstly, the elaboration of a quality synthetic indicator on processes and products of the mills. Secondly, social network analysis is applied to the technical/managerial advice networks of the mills. Thirdly, a mill typology was established by means of factor analysis which employs quality and relational indicators. It is proved that the Regulatory Boards, as well as the second-step cooperatives, can assume a role of integrating poles with respect to the collective action developed in the LAFS, particularly in terms of dissemination of knowledge and innovations, which enhances the process and product quality of local firms. The existence of networks is a necessary condition to improve and homogenize the quality in a diffuse local agro-food structure
Modeling and design of a combined transverse and axial flow threshing unit for rice harvesters
Get PDFThe thorough investigation of both grain threshing and grain separating processes is a crucial consideration for effective structural design and variable optimization of the tangential flow threshing cylinder and longitudinal axial flow threshing cylinder composite units (TLFC unit) of small and medium-sized (SME) combine harvesters. The objective of this paper was to obtain the structural variables of a TLFC unit by theoretical modeling and experimentation on a tangential flow threshing cylinder unit (TFC unit) and longitudinal axial flow threshing cylinder unit (LFC unit). Threshing and separation equations for five types of threshing teeth (knife bar, trapezoidal tooth, spike tooth, rasp bar, and rectangular bar), were obtained using probability theory. Results demonstrate that the threshing and separation capacity of the knife bar TFC unit was stronger than the other threshing teeth. The length of the LFC unit was divided into four sections, with helical blades on the first section (0-0.17 m), the spike tooth on the second section (0.17-1.48 m), the trapezoidal tooth on the third section (1.48-2.91 m), and the discharge plate on the fourth section (2.91-3.35 m). Test results showed an un-threshed grain rate of 0.243%, un-separated grain rate of 0.346%, and broken grain rate of 0.184%. Evidenced by these results, threshing and separation performance is significantly improved by analyzing and optimizing the structure and variables of a TLFC unit. The results of this research can be used to successfully design the TLFC unit of small and medium-sized (SME) combine harvesters
Regional livestock grazing, human demography and fire incidence in the Portuguese landscape
Get PDFAim of study:Wildfire incidence in Portugal is high in comparison with other Mediterranean Europe countries. Wildfire problems have been worsened by complex interactions between land use, livestock grazing and human population during the 20th century. In this study we try to understand these interactions and relationships.Area of study: Portugal country. Material and Methods: For the mainland Portuguese territory we present a statistical temporal analysis (1930-2001) based on the densities of livestock grazing and human inhabitants at the smallest administrative unit level, the parish. We compare these data with fire incidence descriptors (average area burned and average fire density) between 1990 and 2007. Research highlights: We have identified clusters of parishes sharing common trends in the evolution of livestock and human inhabitant densities. A cause-effect relationship was not detected between livestock grazing density and fire incidence. However, the results point out clusters of parishes where conflicts between forest, fire and livestock grazing are important in the North, Centre and South regions of Portugal.Key Words: Livestock grazing; inhabitants; forest; fire; vegetation
Is truffle brûlé a case of perturbational niche construction?
Get PDFAim of study: in the context of niche construction theory, the investigation was aimed at assessing if truffle brûlé is a case of niche construction by testing if the disappearance of grasses in the brûlé induces a non-arbitrary perturbation in the soil physical environment and, in that case, which are the physical processes involved.Area of study: a natural truffle bed located in the Italian Apennines inside an experimental truffle-producing area of the University of Perugia.Material and methods: Three aggregate size classes in the soil of a brûlé and of the neighbouring grass-covered area were determined with the wet-sieving technique in accordance with international standards. In the first part of the investigation, the area was sampled according to a systematic sampling design and the spatial patterns of aggregate size classes in the brûlé and in the neighbouring grass-covered area were compared by means of geostatistics. In the second part, the suppression of grasses in the brûlé was mimicked in the laboratory by removing roots from a sample collected in the grass-covered area and the effect of freeze-thaw cycles was tested by comparing a control treatment to other four treatments consisting in sub-samples equilibrated at a water tension of -2.5, -5, -10 and -20 kPa. Samples were submitted to a number of freeze-thaw cycles equal to those recorded in the area, analysed for aggregate size distribution and compared with univariate ANOVA.Main results: The aggregate size classes larger than 0.25mm displayed a spatial pattern comparable to that of the brûlé, with sharp changes along the boundaries of the brûlé itself. The laboratory experiment showed that such changes are attributable to freeze-thaw cycles that in one winter season may produce a significant decrease in aggregate size compared to the grass-covered area. Both results indicate that the disappearance of grasses in the brûlé fulfils the requirement of perturbational niche construction.Research highlights: the observed change of soil aggregation in the brûlé can be useful in delineating soils suitable for truffle farming and in creating suitable soil physical conditions for truffle production by exploiting freeze-thaw cycles after irrigation in winter.Keywords: aggregates; brûlé; niche construction; Tuber, soil structure
Mixed stands of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst] can be more productive than monocultures. Evidence from over 100 years of observation of long-term experiments
Get PDFAim of study: The objective of this study was to analyse the effect of species mixing of Scots pine and Norway spruce on the productivity at the stand and species level. We also analysed to what extent the mixing effects is modified by drought stress.Area of study: The study was conducted inN-E Poland and based on three experiments located in Maskulińskie, Strzałowo and Kwidzyn Forest Districts.Material and methods: We evaluated long-term mixed-species experiments in Scots pine and Norway spruce which are under continuous survey since more than 100 years. Stand productivity was analysed based on the periodic annual increment and total yield of stem volume. Growth and yield were compared between mixed and neighbouring pure stands. As a substitute for the missing Norway spruce monocultures, we used appropriate yield table data. In order to characterize the effect of water supply on the mixing effects, we correlated the Martonne index of aridity with the ratio of Scots pine growth in mixed versus pure stands.Main results: We found that the mixed stands exceed the weighted mean of the pure stands’ volume productivity on average by 41%. At the species level Scots pine benefits from the mixture by 34% and Norway spruce by 83%. Growth periods with harsh climate conditions reinforce overyielding, while periods with mild conditions reduce the benefit of mixing. The overyielding of mixed stands, especially when growing under unfavourable conditions, is explained by niche complementarity of both species and discussed in view of the stress-gradient-hypothesis.Research highlights: The revealed overyielding of mixed compared with neighbouring pure stands, particularly under harsh weather conditions, substantiates the preferences of Scots pine-Norway spruce mixtures regarding climate change. Keywords: drought resilience; mixed stand; pure stand; facilitation; competition; overyielding; underyielding
A maximum entropy model for predicting wild boar distribution in Spain
Get PDFWild boar (Sus scrofa) populations in many areas of the Palearctic including the Iberian Peninsula have grown continuously over the last century. This increase has led to numerous different types of conflicts due to the damage these mammals can cause to agriculture, the problems they create in the conservation of natural areas, and the threat they pose to animal health. In the context of both wildlife management and the design of health programs for disease control, it is essential to know how wild boar are distributed on a large spatial scale. Given that the quantifying of the distribution of wild species using census techniques is virtually impossible in the case of large-scale studies, modeling techniques have thus to be used instead to estimate animals’ distributions, densities, and abundances. In this study, the potential distribution of wild boar in Spain was predicted by integrating data of presence and environmental variables into a MaxEnt approach. We built and tested models using 100 bootstrapped replicates. For each replicate or simulation, presence data was divided into two subsets that were used for model fitting (60% of the data) and cross-validation (40% of the data). The final model was found to be accurate with an area under the receiver operating characteristic curve (AUC) value of 0.79. Six explanatory variables for predicting wild boar distribution were identified on the basis of the percentage of their contribution to the model. The model exhibited a high degree of predictive accuracy, which has been confirmed by its agreement with satellite images and field surveys
