Spanish Journal of Agricultural Research
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Simulation of local head loss of drip-irrigation tape with integrated in-line emitters as a function of cross section
No full textAim of study: To investigate how the cross section of a drip-irrigation tape affects local head loss.Area of study: The work was carried out in the laboratory of Irrigation hydraulics, College of Water Conservancy and Environment, Three Gorges University, Yichang, Hubei province.Material and methods: Tapes with six different wall thicknesses were studied experimentally to determine the relationship between cross-section deformation, wall thickness, and pressure. Based on the experimental results, we determined the factors that influence local head loss in drip-irrigation tapes by numerical simulation and dimensional analysis.Main results: The cross-sectional shape of the drip-irrigation tape varied with pressure: under low pressure, the cross section was nearly elliptical. The cross-sectional shape of the tape strongly influenced the local head loss, which was inversely proportional to the 0.867th power of the flattening coefficient of the drip irrigation tape. We expressed the local head loss of a drip-irrigation tape equipped with integrated in-line emitters by considering the deformation of the cross section. Under the conditions used in this study, when the cross section is circular, the ratio of local head loss to frictional head loss was about 10% but, when the cross section is elliptical, this ratio increased to 15%.Research highlights: The shape of the cross section of a drip-irrigation tape is nearly elliptical under low pressure. Local head loss is inversely proportional to the 0.867th power of that is the flatting coefficient of the drip-irrigation tape. Local head loss is about 1.5 times for elliptical tape than circular tape
Production efficiency of green beans integrated with tilapia in a circular farming system of media-filled aquaponics
No full textAim of study: To evaluate the biomass production of green bean (Phaseolus vulgaris) in a media-filled aquaponics system together with Genetically Improved Farmed Tilapia, GIFT (Oreochromis niloticus).Area of study: Kota Kinabalu, Sabah (Malaysia).Material and methods: The experiment involved modulating and optimizing the density of extractive species (plants) in the hydroponic tank (55 cm × 35 cm). Five treatments were carried out: T0 (control-without plant), T2 (2 plants), T4 (4 plants), T8 (8 plants), T12 (12 plants) where the stocking density of GIFT was 30 tails (identical in all the treatments). Water volume in each treatment was 800 L and the experimental set up was closed recirculating type. The trials were carried out over a period of 90 days.Main results: Growth of the GIFT was not affected by the presence of green bean or by manipulation of the stocking density. Treatment T4 yielded significantly higher biomass production of green beans (1556.4 ± 88.9 g), compared to T2 (1083.6 ± 86.9 g), T8 (404.6 ± 47.9 g), and T12 (401.8 ± 98.1 g). There were noticeable fluctuations in the concentrations of NH3-N (ammonia), NO2-N (nitrite), NO3-N (nitrate) and PO4-P (phosphate) over the experimental period that indicated the process of nitrification and absorption of nutrients.Research highlights: The nitrogenous waste produced by the fish supported the biomass of the green beans in the aquaponics system and the waste uptake of this extractive species is effective enough for reuse of the water for rearing of GIFT
Improving the monitoring of corn phenology in large agricultural areas using remote sensing data series
No full textAim of study: Mexico's large irrigation areas demand non-structural actions to improve the irrigation service, such as monitoring crop phenology; however, its application has been limited by the large volumes of field information generated, diversity of crop management and climatic variability. The objective of this study was to generate and validate a methodology to monitor corn (Zea mays L.) phenology from the historical relationship of the vegetation indexes (VIs), EVI and NDVI, with the phenological development (PD) of corn grown in large irrigation zones.Area of study: Irrigation District (ID) 075 “Valle del Fuerte”, northern Sinaloa, Mexico.Material and methods: We used a database of 20 years of climate, field crop growth and crop phenology data, and Landsat satellite images. A methodology was proposed on a large scale supported with GIS and remote sensing data series.Main results: The methodology was validated in 19 plots with an acceptable correlation between observed PD and estimated PD for the two VIs, with slightly better values for EVI than for NDVI. NDVI and EVI models agreed with experimental PD observations in 92.1% of the farms used to validate the methodology, in 2.5% only the NDVI model coincided with the real, in 3.1% only the EVI model coincided, and in 2.3% both models disagreed with observation, generated a stage out of phase with respect to the real phenological stage.Research highlights: is possible to generalize the methodology applied to large irrigation zones with remote sensing data and GIS
Genetic variability of Colletotrichum lindemuthianum isolates from Turkey and resistance of Turkish bean cultivars
No full textAim of study: To evaluate genetic variability and population structure of C. lindemuthianum isolates in Turkey and to record the reactions of some common bean cultivars to the pathogen isolates representing different genetic groups.Area of study: The study was performed in seven provinces of Turkey.Material and methods: Genetic diversity of 91 C. lindemuthianum isolates obtained from different provinces of Turkey was characterized by 27 iPBS and 30 ISSR primers. Also, the resistance of 40 common bean cultivars was scored against three isolates representing different genetic groups.Main results: The dendrogram based on the combined dataset of iPBS and ISSR markers classified the isolates into two main groups with a genetic similarity of 72%, which closely associated with the geographic distribution of the isolates. The dendrogram of Nei’s genetic distances and Structure analysis supported the clustering of C. lindemuthianum isolates according to the geographical provinces. The results indicated that high level of genetic diversity (GST= 0.4) and low level of gene flow (NM=0.748) exist among the populations. AMOVA analysis showed that 58.7% of total genetic variability resulted from genetic differences between the isolates within populations, while 41.29% was among populations. Four cultivars showed resistant reaction to three isolates, while the other cultivars were susceptible to at least one isolate.Research highlights: The results indicated that iPBS and ISSR markers were reliable and effective tools for analyzing population structure of C. lindemuthianum and revealed high level of genetic and pathogenic diversity among pathogen populations in Turkey
Development of a SNP parentage assignment panel in some North-Eastern Spanish meat sheep breeds
No full textAim of study: To validate two existing single nucleotide polymorphism (SNP) panels for parentage assignment in sheep, and develop a cost effective genotyping system to use in some North-Eastern Spanish meat sheep populations for accurate pedigree assignment.Area of study: SpainMaterial and methods: Nine sheep breeds were sampled: Rasa Aragonesa (n=38), Navarra (n=39), Ansotana (n=41), Xisqueta (n=41), Churra Tensina (n=38), Maellana (39), Roya Bilbilitana (n=24), Ojinegra (n=36) and Cartera (n=39), and these animals were genotyped with the Illumina OvineSNP50 BeadChip array. Genotypes were extracted from the sets of 249 SNPs and 163 SNPs for parentage assignment designed in France and North America, respectively. Validation of a selected cost-effective genotyping panel of 158 SNPs from the French panel were performed by Kompetitive allele specific PCR (KASP). Additionally, some functional SNPs (n=15) were also genotyped.Main results: The set of 249 SNPs for parentage assignment showed better diversity, probability of identity, and exclusion probabilities than the set of 163 SNPs. The average minor allele frequency for the set of 249, 163 and 158 SNPs were 0.41 + 0.01, 0.39 + 0.01 and 0.42 + 0.01, respectively. The parentage assignment rate was highly dependent to the percentage of putative sires genotyped.Research highlights: The described method is a cost-effective genotyping system combining the genotyping of SNPs for the parentage assignment with some functional SNPs, which was successfully used in some Spanish meat sheep breeds
Characterization and challenges of livestock farming in Mediterranean protected mountain areas (Sierra Nevada, Spain)
No full textAim of study: To characterize and analyse the extensive livestock farming systems in environmental protected area and propose strategies for their sustainable improvement.Area of study: Sierra Nevada Protected Area (Spain)Material and methods: Data were collected from a sample of 85 farmers and 48 experts. The information from farmers was expressed in 35 variables, 23 of which were qualitative and 12 quantitative. A multivariate analysis was conducted.Main results: The principal components explained 71.2% of the total variance and the k-means cluster analysis identified three groups: C1 (38 farms), medium-size farms with a predominance of goats and relative dairy specialization; C2 (12 farms), large-size farms with extensive grazing lands, a high proportion of meat purpose animals and managed by young and dynamic farmers and C3 (35 farms), medium-size farms with a high proportion of meat purpose animals and undeveloped business management. The main problems reported were: insufficient pastures for livestock, stagnation of product prices, lack of generational renewal and need for social recognition of livestock farming. These obstacles could be overcome by implementing measures aimed at improving feed self-sufficiency -and thus reduce production costs- increasing income through social recognition of farming, achieving product differentiation, and strengthening short marketing channels. This would be favoured by an increase in associationism and specialized training.Research highlights: Farm management and marketing are important for improve these farming systems. The extensive livestock farming continues to be an important activity in European protected mountain areas
Relevance of the study of metabolic profiles in sheep and goat flock. Present and future: A review
No full textCurrent adoption of technical methods of the production systems and the genetic improvement of flocks’ productivity have led to the emergence of the well-known metabolic diseases or diseases linked to production. These disorders affect the health status of the flock, thereby generating strong economic losses in the livestock sector. The solution goes through the assessment of the ration, the characteristics of the facilities, the physiological state and the health of the flock, but also, assessing the health condition which is not always reflected in their body condition or feed intake. In field conditions, metabolic profiles could be considered as possible intermediate monitoring tool between animal production and nutrition, because they are able to express a(n) (im)balance between production requirements and feed intake. This information can be accessed by performing measurements and interpreting different blood parameters in a clinical context. Thus, the aim of this review is to offer current information about biochemical metabolic parameters in small ruminants, covering some influencing aspects related to sampling procedure, management and interpretation of results
Seasonal variations of carcass characteristics, meat quality and nutrition value in Iberian wild red deer
No full textAim of study: The effects of hunting season (autumn vs. winter) on carcass characteristics and meat quality of Iberian wild red deer were assessed.Area of study: A total of 100 males of wild red deer of Iberian genetic line (Cervus elaphus) were hunted on Ciudad Real (south central Spain).Material and methods: Yields for shoulder (with bone), neck, backbone, loin, tenderloin, leg (with bone), short plate and flank were determined. In addition, samples of Longissimus thoracis et lumborum and Rectus abdominis muscles were collected. Then, pH48, colour measurements, chemical composition, cooking loss, Warner Bratzler shear blade, fatty acid and amino acid profiles and mineral content were analyzed.Main results: Deer hunted in autumn (n=50) had higher (p<0.01) yields of shoulder, backbone and short plate and higher contents of intramuscular fat (IMF), cholesterol and K, Fe and Mn but lower (p<0.001) pH48 and Na, Mg, Zn and Cu contents than deer hunted in winter (n=50). Shear force tended (p=0.05) to be lower for meat collected in autumn than for meat collected in winter. However, loin yield was 59.2% higher (p<0.001) for winter than for autumn carcasses. Deer hunted in winter had higher α-linoleic acid (p<0.05) and long chain n-3 polyunsaturated (p<0.001) percentages than deer hunted in autumn.Research highlights: Autumn hunting is recommended to obtain carcasses with higher yields of shoulder, backbone and short plate and meat with higher IMF. Conversely, winter hunting is advisable for higher loin yield and for a profile richer in polyunsaturated fatty acids
Maintaining intestinal microflora balance in heat-stressed broilers using dietary creeping wood sorrel (Oxalis corniculata) powder and chromium (chromium picolinate)
No full textThis study aimed to determine the effect of dietary creeping wood sorrel powder (Oxalis corniculata) and chromium supplemented to broilers (1-42 days) exposed to heat stress, on their performance and on the intestinal and caecal microbiota.Area of study: Ilfov, RomaniaMaterial and methods: The feeding trial was conducted on 60, day-old Cobb 500 broilers, divided equally in two groups, each group with six replicates (5 chicks/ replicate). The broilers were housed in an experimental hall at 32° C constant temperature and 23h light regimen. Unlike the dietary control diet (C), the experimental diet (E) was supplemented with 1% creeping wood sorrel powder and 20 mg chromium picolinate/ kg premix. One bird from each replication was slaughtered on days 28 and 42, and samples of caecal and intestinal content were collected for bacteriological analysis.Main results: The dietary creeping wood sorrel powder and chromium supplements for heat-stressed broilers had no significant influence on their growth performance (1-42 d). Overall, E diet had a beneficial effect on the balance of the caecal microflora; however, in the intestine, E diet had a positive influence on the balance of the intestinal microflora, only for the samples collected at 28 days.Research highlights: Dietary creeping wood sorrel powder and chromium supplements can be an efficient tool for maintaining a proper balance of intestinal microflora in heat-stressed broilers.
Exploring rural tourism experiences through subjective perceptions: A visual Q approach
No full textAim of study: To explore rural tourists’ views in order to identify different market segmentation in relation to rural tourism experiences.Area of study: Spain.Material and methods: Visual Q, a personal subjectivity research methodology, was applied to present both visual and linguistic aspects so that tourists can more intuitively recognize and answer questions regarding their experiences. Thus, it enables researchers to explore rural tourism experiences from tourists’ subjective perceptions.Main results: There are three primary segments of tourist experiences in rural tourism: ‘Occasion driven visitor’, ‘Active leisure seeker’ and ‘Rural immersion pursuer’ and across all visitors, a common pursuit of ‘A pleasant break’.Research highlights: This paper suggests that rural tourism should offer a range of value propositions, thereby escaping the existing monotonous ones