Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Simulating improved combinations tillage-rotation under dryland conditions
Get PDFCrop simulation models allow analyzing various tillage-rotation combinations and exploring management scenarios. This study was conducted to test the DSSAT (Decision Support System for Agrotechnology Transfer) modelling system in rainfed semiarid central Spain. The focus is on the combined effect of tillage system and winter cereal-based rotations (cereal/legume/fallow) on the crop yield and soil quality. The observed data come from a 16-year field experiment. The CERES and CROPGRO models, included in DSSAT v4.5, were used to simulate crop growth and yield, and DSSAT-CENTURY was used in the soil organic carbon (SOC) and soil nitrogen (SN) simulations. Genetic coefficients were calibrated using part of the observed data. Field observations showed that barley grain yield was lower for continuous cereal (BB) than for vetch (VB) and fallow (FB) rotations for both tillage systems. The CERES-Barley model also reflected this trend. The model predicted higher yield in the conventional tillage (CT) than in the no tillage (NT) probably due to the higher nitrogen availability in the CT, shown in the simulations. The SOC and SN in the top layer only, were higher in NT than in CT, and decreased with depth in both simulated and observed values. These results suggest that CT-VB and CT-FB were the best combinations for the dry land conditions studied. However, CT presented lower SN and SOC content than NT. This study shows how models can be a useful tool for assessing and predicting crop growth and yield, under different management systems and under specific edapho-climatic conditions
Field efficacy against the hazelnut weevil, Curculio nucum and short-term persistence of entomopathogenic nematodes
Get PDFThe hazelnut weevil, Curculio nucum L. (Coleoptera: Curculionidae) is a pest affecting hazelnut orchards in Europe, with an important economical repercussion. Its potential control, short-term field persistence and the vertical distribution of native entomopathogenic nematode strains were tested in Muntanyes de Prades, Tarragona (NE Iberian Peninsula) over two consecutive years. Steinernema feltiae strain D114, Steinernema sp. strain D122 and Heterorhabditis bacteriophora strain DG46 were used in summer and spring applications at a dosage of 5·105 IJs m-2. The three nematode species reduced the hazelnut weevil population, ranging from 32% to 88% efficacy, without significant differences in efficacy or between the two applications. Persistence evaluation was carried out during 9 weeks for S. feltiae (D114), Steinernema sp. (D122) and H. bacteriophora (DG46) and showed all species capable of lasting for this period. Nematodes and larval vertical distribution was assessed. Most of the hazelnut weevil stayed within the first 25 cm although some were found as deep as 40 cm. Entomopathogenic nematodes were found along all 40 cm depth. This study proves the suitability of entomopathogenic nematodes to control the hazelnut weevil
Short communication. PCR detection of DNA of bovine, ovine-caprine and porcine origin in feed as part of a bovine spongiform encephalopathy control program
Get PDFThe rapid identification of residues of mammalian materials in animal feedstuffs is important for the effective control of feed as a potential source of transmission of bovine spongiform encephalopathy (BSE). It is included in the monitoring program developed to avoid the appearance of this disease. In the present work a PCR analysis was tested for the detection of mammalian residues (bovine, caprine, ovine and porcine). The DNA extraction method utilised guanidium thiocianate, and primers flanking a conserved region of mitochondrial DNA were synthesized for each species. PCR tests were specific for each species and allowed detection in feedstuffs of levels as low as 1% of bovine DNA and 1.5% of ovine, caprine and porcine DNA. These PCR tests may allow the rapid detection of residues of these species constituting a powerful tool against BS
New trends in rabbit feeding: influence of nutrition on intestinal health. A review
No full textThe role of gut barrier against pathogens and its interaction with dietary factors in weaned rabbits affected with digestive disorders, especially epizootic rabbit enteropathy is reviewed. This interaction was studied identifying nutritive factors that influence gut barrier function of mucosa. It was examined the morphology, and enzyme activity of mucosa and the gut associated immune system. Besides, it was characterized the substrate that reaches the caecum and its capacity to favour pathogen bacteria growth, by reviewing the effect of diet on ileal digestibility of nutrients, transit time and microbiota population. The nutritional factors which affect health of early weaned rabbits are level and type of both fibre and protein. The optimal dietary level of insoluble fibre to minimise mortality is 30-32%. Furthermore, a moderate inclusion of soluble fibre (12%) improves mucosa integrity and decreases mortality and the frequency of detection of Clostridium perfringens and Campylobacter spp in the caecum. The reduction of ileal nitrogen flow had a positive effect on pups viability and frequency of detection of C. perfringens. Furthermore, dietary supplementation with 1% of glutamine reduced fattening mortality, the frequency of detection of C. perfringens, and Helicobacter spp, and diminished the counts of Eimeria spp at the jejunum. In conclusion, a correct diet formulation may help to limit the epizootic rabbit enteropathy incidence in weaned rabbits
Short Communication. Comparing flammability traits among fire-stricken (low elevation) and non fire-stricken (high elevation) conifer forest species of Europe: A test of the Mutch hypothesis
Get PDFAim of study. The flammability of the main coniferous forest species of Europe, divided into two groups according to their fire regime and altitudinal distribution, was tested in an effort to detect species-specific differences that may have an influence on community-wide fire regimes.Area of study. Conifer species comprising low- and high-elevation forests in Europe.Materials and Methods. The following conifer species were tested: low elevation; Pinus halepensis (Aleppo pine), Pinus brutia (Turkish pine), Pinus pinaster (maritime pine), Pinus pinea (stone pine) and Cupressus sempervirens (cypress), high elevation (i.e., above 600 m a.s.l.); Pinus sylvestris (Scots pine), Abies alba (white fir), Picea excelsa (Norway spruce), Abies borissii regis (Macedonian fir) and Pinus nigra (black pine). Flammability assessment (time-to-ignition and ignition temperature) was conducted by an innovative ignition apparatus, heat content was measured with an IKA Adiabatic Bomb Calorimeter and ash content by heating 5 g of plant material in a muffle furnace at 650ºC for 1 h. Differences among species was statistically analysed by Duncan’s multiple comparison test.Main results. The results did not distinguish separate groups among traits between fire- and non-fire-stricken communities at the individual species level.Research highlights. Differences in fire regimes among low and high elevation conifer forests could be attributed either to differences in flammability of the plant communities as a whole (i.e., fuelbed or canopy properties vs. individual fuel properties) or to other factors (climatic or anthropogenic).Key words: flammability; ignitability; heat content; ash content; conifer species; Mutch hypothesis
Short Communication. Restoring monoculture plantation using stand spatial structure analysis
Get PDFAim of study. To improve the quality of monoculture plantations in China.Area of study. structure-based forest management was conducted in Rocky Mountain Area of Northern China.Material and Methods. Stand spatial structure indicators of mingling degree, uniform angle index, neighborhood comparison and opening degree were comparably investigated to understand the changes of Pinus tabulaeformis plantations.Main results. The results indicated that structure-based forest management accounted for 0.403 and 0.448 of the significant variations in mingling degree and opening degree increments, and had no essential changes in uniform angle index and neighborhood comparison. Structure-based forest management is greatly beneficial to plantation quality, and it can be a source of improvement on stand structure.Research highlights. This improved information is essential to provide a firm basis for future policy-making on how best to restore degraded forests in China as well as the rest of the world.Key words: monoculture plantation; structure-based forest management; stand spatial structure; forest restoratio
An intercomparison of Satellite Burned Area Maps derived from MODIS, MERIS, SPOT-VEGETATION, and ATSR images. An application to the August 2006 Galicia (Spain) forest fires
Get PDFAim of study: The following paper presents an inter-comparison of three global products: MCD45A1 (MODIS - MODerate resolution Imaging Spectrometer - Burned Area Product), L3JRC (Terrestrial Ecosystem Monitoring Global Burnt Area Product), and GLOBCARBON Burnt Area Estimate (BAE) Product; and three local products, two of them based on MODIS data and the other one based on MERIS (MEdium Resolution Imaging Spectrometer) data.Area of study: The study was applied to the Galician forest fires occurred in 2006.Materials and Methods: Materials used involved the three already mentioned global products together with two MODIS and one MERIS reflectance images, and MODIS thermal anomalies. The algorithm we used, which is based on the determination of thresholds values on infrared bands, allowed the identification of burned pixels. The determination of such threshold values was based on the maximum spatial correlation between MODIS thermal anomalies, and infrared reflectance values. This methodology was applied to MODIS and MERIS reflectance bands, and to the NBR (Normalized Burn Ratio). Burned area validation was evaluated using burned area polygons as derived from an AWiFS (Advanced Wide Field Sensor) image of 60m pixel size.Main results: Best results were reached when using the MERIS infrared bands, followed by the MODIS infrared bands. Worst results were reached when using the MCD45A1 product, which clearly overestimated; and when using the L3JRC product, which clearly underestimated.Research highlights: Since the efficiency of the performance of the available burned area products is highly variable, much work is needed in terms of comparison among the available sensors, the burned area mapping algorithms and the resulting products.Keywords: forest fires; MODIS; MERIS; MCD45A1; L3JRC; GLOBCARBON-BAE; SPOT-VEGETATION; ATSR.Abbreviations used: ATSR: Along Scanning Radiometer; AVHRR: Advanced Very High Resolution Radiometer; AWiFS: Advanced Wide Field Sensor; EOS: Earth Observation System; ESA: European Space Agency; GBA2000: Global Burnt Area 2000; GLOBCARBON-BAE: GLOBCARBON Burnt Area Estimate Product; L3JRC: Terrestrial Ecosystem Monitoring Global Burnt Area Product; MCD45A1: MODIS Burned Area Product; MERIS: MEdium Resolution Imaging Spectrometer; MOD09GA: Terra MODIS Surface Reflectance Daily L2G Global 500 m; MOD09GQ: Terra MODIS Surface Reflectance Daily L2G Global 250 m; MODIS: MODerate resolution Imaging Spectrometer; NBR: Normalized Burn Ratio; NDVI: Normalized Difference Vegetation Index; NIR: near-infrared; SPOT: Satellite Pour l’Observation de la Terre; SWIR: short-wave infrared; UTM: Universal Transverse Mercator
Distance-independent individual tree diameter-increment model for Thuya [Tetraclinis articulata (VAHL.) MAST.] stands in Tunisia
Get PDFAim of study: The aim of the work was to develop an individual tree diameter-increment model for Thuya (Tetraclinis articulata) in Tunisia.Area of study: The natural Tetraclinis articulata stands at Jbel Lattrech in north-eastern of Tunisia.Material and methods: Data came from 200 trees located in 50 sample plots. The diameter at age t and the diameter increment for the last five years obtained from cores taken at breast height were measured for each tree. Four difference equations derived from the base functions of Richards, Lundqvist, Hossfeld IV and Weibull were tested using the age-independent formulations of the growth functions. Both numerical and graphical analyses were used to evaluate the performance of the candidate models.Main results: Based on the analysis, the age-independent difference equation derived from the base function Richards model was selected. Two of the three parameters (growth rate and shape parameter) of the retained model were related to site quality, represented by a Growth Index, stand density and the basal area in larger trees divided by diameter of the subject tree expressing the inter-tree competition.Research highlights: The proposed model can be useful for predicting the diameter growth of Tetraclinis articulata in Tunisia when age is not available or for trees growing in uneven-aged stands.Keywords: Age-independent growth model; difference equations; Tetraclinis articulata; Tunisia
Large wildland fires in three diverse regions in Spain from 1978 to 2010.
Get PDFAim of study: Large wildland fires (LWF) are major disturbance processes affecting many ecosystems each year. In last decades, socio-economic changes have contributed to major changes in land uses. This study assess trends in number, burned area and average size of large wildfires (> 100 ha) from 1978 to 2010 in Spain.Area of study: This work analyzes three clearly different regions of Spain (Mediterranean coast, MC, Mediterranean Interior, MI, Northwestern Spain, NW).Material and Methods: We studied historical wildland fire data from Spain’s EGIF database (General Statistics on Wildland Fires). We selected only wildland fires larger than 100 ha. All LWF were analyzed to test trends in number of fires, burned area and mean fire size.Main results: The number of LWF decreased in all regions but the burned area only decreased in MC and NW regions. However, both the number of LWF and the burned area did not decrease after 1995 in any region. The average size of LWF did not change in any of the three regions. Fires larger than 500 ha were very significant due to the high percentage of area burned in relation to the total area burned by fires larger than 100 ha (79.3 % in MC, 63.9 % in MI, and 35.7% in NW).Research highlights: After 1995, the number of LWF and burned area did not decrease. Additional actions are required including learned lessons from past LWF spread, and better trained fire suppression workers and more fuel management.Keywords: large wildland fires; trends; forest management; Spain
Remote Monitoring of Forest Insect Defoliation -A Review-
Get PDFAim of study: This paper reviews the global research during the last 6 years (2007-2012) on the state, trends and potential of remote sensing for detecting, mapping and monitoring forest defoliation caused by insects.Area of study: The review covers research carried out within different countries in Europe and America.Main results: A nation or region wide monitoring system should be scaled in two levels, one using time-series with moderate to coarse resolutions, and the other with fine or high resolution. Thus, MODIS data is increasingly used for early warning detection, whereas Landsat data is predominant in defoliation damage research. Furthermore, ALS data currently stands as the more promising option for operative detection of defoliation.Vegetation indices based on infrared-medium/near-infrared ratios and on moisture content indicators are of great potential for mapping insect pest defoliation, although NDVI is the most widely used and tested.Research highlights: Among most promising methods for insect defoliation monitoring are Spectral Mixture Analysis, best suited for detection due to its sub-pixel recognition enhancing multispectral data, and use of logistic models as function of vegetation index change between two dates, recommended for predicting defoliation.Key words: vegetation damage; pest outbreak; spectral change detection