Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Linking hypothesized causal factors to aboveground biomass growth in forests of Alabama and the eastern United States
Get PDFAim of study: We analyzed the hypothesized causal effects of relative density, density, height, species richness, species diversity, temperature, precipitation, and slope on above ground biomass growth (AGBG).Area of study: Eastern region of the USA.Materials and methods: We used the USDA Forest Service’s Forest Inventory and Analysis (FIA) database. A total of 2554 plots from all stand ages, regardless of disturbance history, were selected from the state of Alabama and 967 plots of stand age under 30 years and no prior disturbance were selected from the eastern US. We analyzed the data using descriptive statistics and structural equation modeling.Main results: Relative stand density exhibited a strong positive direct effect on AGBG, especially in the young forests (path coefficient 0.79), but a weaker indirect effect through species richness/diversity. Tree height influenced positively AGBG directly and indirectly through relative density and species richness. The effect of temperature and slope was greater than the effect of species richness/diversity on AGBG in the young forests of the eastern US.Research highlights: For the forests of the eastern US, greater tree species diversity did not appear to result in neither greater nor lower productivity. The diversity-productivity relationship was negative in forests of Alabama, however, where prior management likely resulted in removal of select dominant trees from valuable species (i.e., high-grading).
Applying quantitative structure models to plot-based terrestrial laser data to assess dendrometric parameters in dense mixed forests
Get PDFAim of study: To assess terrestrial laser scanning (TLS) accuracy in estimating biometrical forest parameters at plot-based level in order to replace manual survey for forest inventory purposes.Area of study: Monte Morello, Tuscany region, ItalyMaterial and methods: In 14 plots (10 m radius) in dense Mediterranean mixed conifer forests, diameter at breast height (DBH) and height were measured in Summer 2016. Tree volume was computed using the second Italian National Forest Inventory (INFC II) equations. TLS data were acquired in the same plots and quantitative structure models (QSMs) were applied to TLS data to compute dendrometric parameters. Tree parameters measured in field survey, i.e. DBH, height, and computed volume, were compared to those resulting from TLS data processing. The effect of distance from the plot boundary in the accuracy of DBH, height and volume estimation from TLS data was tested.Main results: TLS-derived DBH showed a good correlation with the traditional forest inventory data (R2=0.98, RRMSE=7.81%), while tree height was less correlated with the traditional forest inventory data (R2=0.60, RRMSE=16.99%). Poor agreement was observed when comparing the volume from TLS data with volume estimated from the INFC II prediction equations.Research highlights: The study demonstrated that the application of QSM to plot-based terrestrial laser data generates errors in plots with high density of coniferous trees. A buffer zone of 5 m would help reduce the error of 35% and 42% respectively in height estimation for all trees and in volume estimation for broadleaved trees
Using manure as fertilizer for maize could improve sustainability of milk production
Get PDFThis study evaluated the effect of organic or chemical fertilization of maize on cow performance, economic outcomes, and greenhouse gas emission. Each type of maize silage according its different fertilization was used in two rations offered to two different groups of nine Friesian-Holstein cows throughout 4 months. The production cost of the maize silage was 8.8% lower for organic than for chemical fertilization. Both silages had similar nutritive value, except a higher concentration of starch in maize with organic fertilization, which allowed a reduction in the proportion of concentrate in the ration, saving 25.3 eurocents per cow in the daily ration, generating a positive balance of 21.8 eurocents per cow and day. The milk yield and composition were unaffected depending on the type of fertilization, whereas the estimation of CH4 and N2O emissions with chemical fertilization was higher than emissions with organic fertilization. As a result, it is possible to increase the sustainability and profitability of dairy production with reuse and recycling of manure
Development of a model to calculate the overall heat transfer coefficient of greenhouse covers
Get PDFA Building Energy Simulation (BES) model based on TRNSYS, was developed to investigate the overall heat transfer coefficient (U-value) of greenhouse covers including polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), and horticultural glass (HG). This was used to determine the influences of inside-to-outside temperature difference, wind speed, and night sky radiation on the U-values of these materials. The model was calibrated using published values of the inside and outside convective heat transfer coefficients. Validation of the model was demonstrated by the agreement between the computed and experimental results for a single-layer PE film. The results from the BES model showed significant changes in U-value in response to variations in weather parameters and the use of single or double layer greenhouse covers. It was found that the U-value of PC, PVC, and HG was 9%, 4%, and 15% lower, respectively, than that for PE. In addition, by using double glazing a 34% reduction in heat loss was noted. For the given temperature U-value increases as wind speed increases. The slopes at the temperature differences of 20, 30, 40, and 50 °C, were approximately 0.3, 0.5, 0.7, and 0.9, respectively. The results agree with those put forward by other researchers. Hence, the presented model is reliable and can play a valuable role in future work on greenhouse energy modelling
Protective effect of mangrove (Rhizophora apiculata) leaves extract in shrimp (Penaeus monodon) larvae against bio-luminescent disease-causing Vibrio harveyi bacteria
Get PDFApplication of chemicals for monitoring if Vibrio outbreaks can enhance resistance in mangrove (Rhizophora apiculata) leaves extract was tested against bioluminescence disease-causing Vibrio harveyi bacteria. An inhibitory zone of 12 mm was observed at 350 µg/mL The growth of V. harveyi was decreased from 0.783 to 0.533 (OD600) as compared to control (0.970 to 1.031 OD) against R. apiculata extract. The extract was treated against virulence produced by V. harveyi, the crude bacteriocin values decreased from 1.653 to 1.574 OD as compared with control. Further, extract 200 mg/mL was challenged against V. harveyi (10 mL at 1.8 OD600) during larviculture of Penaeus monodon for 30 days. The mortality increased from 9.0 to 68.5% in the control, but in the treatment the mortality varied from 0 to 57.8% till 30th day. The difference in the decrease of mortality in the treatments was 10.6%. V. harveyi count was decreased from 1.46 × 105 to 3 × 103 cfu/mL, respectively in the treatment for the 30th day as compared to control (1.33×105 to 9.2×103 cfu/mL). R. apiculata leaves extract was reported to have various functional groups of compounds as determined by Fourier Transform Infrared Spectroscopy (FTIR). The GC-MS analysis revealed that the R. apiculata extract contains compounds such as 1, 2-diacetate, cyclododecane, 2-chloropropionic acid and squalene. These compounds might be responsible for the antagonism against V. harveyi. Hence, crude extracts of R. apiculata can be used as a non-antibiotic agent to control shrimp disease caused by V. harveyi during larviculture
Milk hygiene in small ruminants: A review
Get PDFSomatic cell count (SCC), mammary pathogens prevalence, total and specific bacterial counts, antimicrobial residues, macroscopic sediment, water addition, aflatoxins and other contaminants constitute the basis for milk payment-schemes, monitoring and improvement of flock hygiene and health management, and development of analytical surveillance programs in the dairy small ruminants. The present work reviews factors influencing the variation of these variables, including milk analytical methods, storage and preservation, along with management implications during the last two decades. Following farmer and cooperative educational programs, progressive reductions have been reported for total bacterial count and antimicrobial residue occurrence in bulk tank milk. These results were consistent, however, with high values for SCC and specific bacterial populations. Thus, mastitis control programs should be intensified to increase hygiene in milk and economic returns for producers and processors. In addition, the implementation of programs to reduce specific bacterial counts (i.e., psychrotrophs, coliforms, Clostridium spp. spores) and mammary pathogen prevalence (i.e., Staph. aureus, Mycoplasma spp.), as well as the use of combined screening methods for an increased rate of antimicrobial detection, are currently required strategies which are positively valuated by milk processors, industry and consumers. Other contaminants may also be present, but cost-effective screening and analytical systems have not yet been implemented. This review aims to be helpful for troubleshooting milk quality and safety, developing future premium payment systems and industry quality-standards, optimizing management, on-farm risk traceability systems and consumer acceptance
Effect of fermented, hardened, and dehulled of chickpea (Cicer arietinum) meals in digestibility and antinutrients in diets for tilapia (Oreochromis niloticus)
Get PDFAmong the most typical feed sources for tilapia, plants represent a low-cost source in substituting for traditional high-cost feed ingredients. Fermentation, hardening and dehulling are common grains processing techniques to make plant nutrients available and more digestible to fish. Apparent digestibility coefficients (ADC) of dry matter and protein, and antinutrients (phytic acid and tannins) in fermented, hardened and dehulled chickpea (Cicer arietinum) meals were determined for juvenile Nile tilapia (Oreochromis niloticus). The highest ADC was obtained with processed (fermented, hardened and dehulled) chickpea meals compared with non-processed. Results indicated that fermentation increased the protein content by 13.1%, decreased the content of ash and phytic acid (47.5 and 45%, respectively), and increased the ingredient apparent digestibility of dry matter (ADM) by 23.2%, and the ingredient apparent digestibility of protein (ADP) by 41.9%. Dehulling meal increased the protein (5.7%) and lipid (6.4%) content of chickpea grains; decreased fiber, ash and tannin content (75.3%, 19.1%, and 84.5%, respectively); and increased ADM by 12.8%, and ADP by 10.4%. We conclude that fermented, hardened and dehulled chickpea meals represent a potential alternative in diets for juvenile O. niloticus
Rearing, bird type and pre-slaughter transport conditions I. Effect on dead on arrival
Get PDFThe transport of broilers to slaughter normally results in a small percentage of dead on arrival (DoA) but little is known about the effects of flock thinning or bird weight. A multivariable linear model was used to analyse the incidence of DoA over one year in 1,856 flocks of Ross broilers (9,188 shipments). Each flock was categorized according to broiler type (yellow-skinned females and males, white-skinned females and males and roaster females) and thinning (birds transported after thinning, remaining birds after thinning and non-thinned flocks), in addition to transport distance, waiting time, maximum and minimum daily temperatures, precipitation and maximum wind speed. The overall percentage of DoA was 0.187%. The effect of the daily maximum outside temperature on DoA was quadratic with minimum DoA at 21.5ºC. Arrival time to the slaughterhouse and waiting time increased DoA by 0.0044% and 0.0021% for every 60 min increase, respectively. DoA were higher in males (which were heavier than females), and in the flocks that were previously thinned. An interaction between thinning and bird type was found, so that DoA were higher in previously thinned flocks of male broilers and roaster females. Despite the high incidence of thinning and larger bird weight, the percentage of DoA was comparable to previous studies. This research provides one of the largest detailed analyses of DoA in commercial broiler production in the Iberian Peninsula. The models described allow to quantify how increases in temperature, transport distance, waiting time, bird weight and the practise of thinning can all increase broiler mortality
Detection of Bactrocera oleae (Diptera: Tephritidae) DNA in the gut of the soil species Pseudoophonus rufipes (Coleoptera: Carabidae)
Get PDFPest control service provided by natural enemies of Bactrocera oleae, the key pest of the olive tree, is nowadays recognized as fundamental. B. oleae has developed resistance to common insecticides, and negative effects both on consumers’ health and non-target species are the major drawbacks of conventional control strategies. Carabid beetles are potential B. oleae pupae predators, but their predation on field still need to be assessed. We tested adult Pseudoophonus rufipes, a species known to be active in olive orchard when pest pupae are abundant in the soil, in order to detect B. oleae pupae consumption at different post feeding times for both male and female carabids. An already existing protocol was used for detecting B. oleae mtDNA sequences of the cytochrome oxidase subunit I gene in carabids’ gut, and its versatility improved. B. oleae mtDNA was detected up to 20 h after pupa ingestion with a high percentage of success, without significant differences between sexes and pair primers used. Prey DNA extraction was tested from both dissected and non-dissected carabids, obtaining comparable results. The trapping system used to collect carabids for molecular assays and the new elements introduced in the protocol represent cost-effective solutions that may be beneficial for future laboratory trials and, mostly, for the analysis of field-collected predators. Fostering the investigation of soil predators in olive orchard may increase the design of conservation control strategies against B. oleae