Spanish Journal of Agricultural Research
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Stocking density influences common carp larval development. Can restocking processes activate compensatory growth consequent to previous high stocking density?
No full textAim of study: to analyse the effect of stocking density on common carp larvae production. Since stocking density is one of the most important variables in recirculating aquaculture system, it is fundamental to understand its implication on fish larval development. Area of study: BrazilMaterial and methods: In an initial trial over a 30-day period, 18,000 Cyprinus carpio larvae were subjected to eight different stocking densities (5, 10, 15, 20, 25, 30, 35 and 40 larvae/L). In a second trial over a 15-day period, the larvae subjected to the 40 larvae/L treatment were selected according to size and 360 of them were subjected to restocking processes at a density of 5 larvae/L, in order to evaluate possible compensatory growth, while those subjected to the 5 larvae/L treatment were likewise selected according to size and were distributed at the same stocking density (5 larvae/L), to be the control treatment during the restocking process.Main results: The larvae kept at the density of 5 larvae/L showed better growth and development. Increased heterogeneity of the concomitant batch was observed with higher stocking density. Restocking at low density (5 larvae/L), for larvae that had previously been kept at high density (40 larvae/L), caused partial compensatory growth, with an increase in the specific growth rate. Increasing the density caused increased productivity up to the density level of 25 larvae/L, but from then on there was no significant difference (p > 0.05).Research highlights: Carp larvae reared at high densities need to be restocked during rearing in order to avoid the “shooting” problem
Commercial growth regulator has adverse effect over soybean seedlings under different cadmium levels
No full textAim of study: Soils contaminated by heavy metals, such as cadmium, may reduce plant development. Exogenous application of plant growth regulators (PGR), are used for optimizing the crops production in stressful environments. The aim of this study was to evaluate the effects of Cd concentrations on the development of soybean seedlings under exogenous application of a commercial PGR.Area of study: Presidente Prudente, São Paulo, Brazil.Material and methods: Soybean seeds were pre-treated in distilled water (control treatment) and in solution with plant growth regulator (PGR treatment) and then germinated with distillated water. The germinated seeds were transferred to different levels of Cd (0, 100, 500 and 900 mg of Cd).Main results: Cd exposure at increasing concentrations, decreased root development, (area, length and volume of roots) and activity of enzymatic antioxidants (SOD, CAT and APX) and enhanced MDA. These responses were accentuated by the PGR exposition. The root morphology and activity of antioxidant enzymes presented "hormesis" responses until 500 mg L-1 of Cd, and the proline content may have played a fundamental role in the maintenance of metabolic activities and biomass.Research highlights: The results indicate that the use of PGR intensified the toxicity responses caused by exposure to increased Cd level. In addition, stress indicators such as MDA content and antioxidant activity in different organs (root and shoot) of soybean seedlings, responded differently according with the use of PGR under exposure of Cd
Impact of 25 years of grazing exclusion and shrub removal on plant community structure and soil characteristics in a xerophytic rangeland
No full textAim of study: We tested the hypothesis that long periods of grazing exclusion in areas with a history of high grazing intensity will have a positive impact on soil nutrient conditions and favor soil infiltration, increase biomass and lead to a recovery in vegetation.Area of study: Noria de Guadalupe, Zacatecas, Mexico.Material and methods: We analyzed the impact of grazing exclusion on biomass, species richness, evenness, soil nutrient content and soil water infiltration after 25 years of exclusion during each of the four seasons by excluding two 15 × 15 m plots of grazing and compared with two control plots.Main results: Exclusion management did not lead to biomass increases; however, it did lead to an important recovery in the plant community. Moreover, soil nutrient content was more affected by the seasonality of rainfall in the study site than by 25 years of exclusion. The elimination of dominant shrubs in the excluded area led to a faster recovery in palatable shrubs and shortgrass vegetation, which was improved by better infiltration values during the end of spring and summer explaining some of the differences in nutrient avaibility.Research highlights: In our study, exclusion management can lead to an important recovery in vegetation without affecting the growth of Atriplex canescens, a valuable source of fodder. Although biomass presented a higher dependence on seasonality and was not related to the treatment, the impact on the forage quality is evident by the different plant communities established after 25 years of exclusion
Short communication: Pepino mosaic virus, a new threat for Serbia’s tomatoes
No full textAim of study: To report the occurrence of Pepino mosaic virus (PepMV) on tomato in Serbia and to genetically characterize Serbian PepMV isolates.Area of study: Tomato samples showing virus-like symptoms were collected in the Bogojevce locality (Jablanica District, Serbia).Material and methods: Collected tomato samples were assayed by DAS-ELISA using antisera against eight economically important or quarantine tomato viruses. Three selected isolates of naturally infected tomato plants were mechanically transmitted to tomato ‘Novosadski jabučar’ seedlings. For confirmation of PepMV infection, RT-PCR was performed using specific primers PepMV TGB F/PepMV UTR R. Maximum-likelihood phylogenetic tree was constructed with 47 complete CP gene sequences of PepMV to determine the genetic relationship of Serbian PepMV isolates with those from other parts of the world.Main results: The results of DAS-ELISA indicated the presence of PepMV in all tested samples. Mechanically inoculated ‘Novosadski jabučar’ seedlings expressed yellow spots and light and dark green patches, bubbling, and curled leaves. All tested tomato plants were RT-PCR positive for the presence of PepMV. The CP sequence analysis revealed that the Serbian PepMV isolates were completely identical among themselves and shared the highest nucleotide identity of 95.1% (99.2% aa identity) with isolate from Spain (FJ263341). Phylogenetic analysis showed clustering of the Serbian PepMV isolates into CH2 strain, but they formed separate subgroup within CH2 strain.Research highlights: This is the first data of the presence of PepMV in protected tomato production in Serbia. Considering increased incidence and rapid spread in Europe, the presence of PepMV on tomato could therefore represent serious threat to this valuable crop in Serbia
Spain’s national network of silos and granaries: architectural and technological change over time
No full textAim of study: To analyse the 670 silos in Spain’s NNSG (National Network of Silos and Granaries), along with the changes in typologies and degree of mechanisation taking place over time.Area of study: Spain.Material and methods: Research began in 2014, collecting NNSG grain storage data across Spain further to the methodology developed by the authors. In a first stage the information was gathered from the FEGA’s general archives in Madrid and the archives of the departments of agriculture in the 13 regions where silos were built. In the second stage of the study, 665 silos were explored in situ. Photographs were taken and information was gathered on their characteristics (general features; architectural features; technological facilities).Main results: This paper discusses the architectural and typological changes taking place over time, from the earliest small, local, richly adorned brick silos to larger, more modern and austere reinforced concrete structures. The machinery with which they are fitted is also addressed, with the progression from basic grain storage to more sophisticated equipment designed to clean, refrigerate or disinfect the grain. Some facilities were used exclusively to select and condition seed for subsequent sowing. The most modern structures, known as macrosilos, are highly mechanised affairs.Research highlights: Spain’s national network of silos and granaries was 41 years in the building. The inventory of the 665 existing silos identified 20 types or subtypes. Early richly adorned units gradually gave way to more austere, functional structures. The machinery in place in silos varied with type/purpose and period of construction
Effect of freezing conservation time on loquat (Eriobotrya japonica) pollen germination
No full textAim of study: Several studies point out that storage at -20 ºC is a suitable method for preserving pollen of many species in the long term. Part of those studies indicate the total storage time at which these conditions are optimal. However, we have found a lack of information about the freezing time conditions and incubation temperature of loquat pollen. The main objective of this study was to evaluate the effect of the -20 ºC conservation temperature on loquat (Eriobotrya japonica (Thunb.) Lindl.) pollen.Area of study: The study was conducted in Montserrat (Valencia, Spain).Material and methods: Loquat flowers were collected in November 2017 and stored at -20 ºC for three time periods: 4 (T1), 6 (T2) and 8 (T3) months. Subsequently, pollen grains were incubated at different temperatures for 72 h. We analyzed (i) the effect of freezing conservation time; (ii) the effect of incubation temperature on germination; (iii) the interaction between these two factors.Main results: T1 showed higher germination percentage and tube length values (mean and maximum) than T2 and T3. The highest germination percentage (52.77%) was detected for T1 at an incubation temperature of 25 ºC. The interaction between freezing time and incubation temperature showed more consistent results for T1 than for T2 and T3.Research highlights: This suggests that storing at -20 ºC for more than 4 months affects pollen grain and reduces germination and pollen growth. Therefore, -20 ºC loquat pollen storage should not exceed 4 months
Short term administration of cyproterone acetate for contraception: Effects on testosterone secretion and semen characteristics in rams (Ovis aries) and bucks (Capra hircus)
No full textAim of study: To examine the influence of administering cyproterone acetate (CPA), at the beginning of the mating season, on the testosterone concentration and morphometric and functional characteristics of ram and buck semen.Area of study: Madrid, SpainMaterial and methods: Five rams and five bucks were intramuscularly administered 200 mg of CPA in 2 mL of olive oil twice per week - from July 1st to 31st in the rams, and from August 1st to 31st in the bucks. Five control animals of each species were administered 2 mL of olive oil. Blood samples and ejaculates analysed from the start of treatment until eight weeks after the last day of treatment.Main results: GLM-ANOVA showed the interaction species × CPA treatment to have effect (p<0.05) on sperm motility, progressive motility and acrosome integrity; and greater effect (p<0.01) on curvilinear velocity (VCL), straight-line velocity (VSL), viability, and morphological abnormalities. In both the rams and bucks, plasma testosterone levels fell from the first week from the start of CPA administration until three weeks after the end of treatment. In rams, the total sperm count, sperm motility, progressive motility, viability, morphological abnormalities, VCL and VSL were all negatively affected by the treatment (p<0.001); acrosome integrity was also affected (p<0.05). In bucks, sperm motility, progressive motility, VCL, VSL and morphological abnormalities were negatively affected (p<0.05).Research highlights: Treatment with CPA affected testosterone secretion, semen characteristics and sperm morphometry in both the rams and bucks, and thus it might be used as short term contraceptive protocol in small ruminants
Governance of knowledge and innovation in the Ibero-American agri-food system
No full textAim of study: Governance and the knowledge and innovation system (KIS) are interrelated concepts. Knowledge management best practices are linked to KIS performance. This article explores the governance of the leading research, development, and innovation institutes in Ibero-American agriculture, food, and agro-industry sector. The paper reports mapping of the governance of 20 agricultural research institutes.Area of study: Latin America and the Caribbean, Spain and Portugal.Material and methods: In total, 51 strategic objectives for effective governance were identified. Self-evaluation by the National Agricultural Research Institutes (NARIs) was validated at a workshop backed by FONTAGRO, a cooperation mechanism amongst Latin American and the Caribbean countries, Portugal and Spain, and the Ibero-American Network of NARIs.Main results: As a strength, the key dimension of NARIs appears to be coordination and cooperation. This result was acknowledged in the internal and external evaluations and supports previous research on the relevance of innovation networks in Latin America. By contrast, as a challenge, the key dimension appears to be demand articulation, followed closely by capacity building. Most of the institutes are also well-positioned to develop deeper ties with social and environmental challenges.Research highlights: In the medium and long term, NARIs should make efforts to improve the processes of organizational evaluation and learning, demand articulation, and strategic direction of the institutions. Improvement in management processes, in addition to best practices for social responsibility and gender equality, appear to be short-term priorities
The cost of mitigating greenhouse gas emissions in farms in Central Andes of Ecuador
No full textAim of study: Reduction of the greenhouse gas (GHG) emissions derived from food production is imperative to meet climate change mitigation targets. Sustainable mitigation strategies also combine improvements in soil fertility and structure, nutrient recycling, and the use more efficient use of water. Many of these strategies are based on agricultural know-how, with proven benefits for farmers and the environment. This paper considers measures that could contribute to emissions reduction in subsistence farming systems and evaluation of management alternatives in the Central Andes of Ecuador. We focused on potato and milk production because they represent two primary employment and income sources in the region’s rural areas and are staple foods in Latin America.Area of study: Central Andes of Ecuador: Carchi, Chimborazo, Cañar provincesMaterial and methods: Our approach to explore the cost and the effectiveness of mitigation measures combines optimisation models with participatory methods.Main results: Results show the difference of mitigation costs between regions which should be taken into account when designing of any potential support given to farmers. They also show that there is a big mitigation potential from applying the studied measures which also lead to increased soil fertility and soil structure improvements due to the increased soil organic carbon.Research highlights: This study shows that marginal abatement cost curves derived for different agro-climatic regions are helpful tools for the development of realistic regional mitigation options for the agricultural sector
Accession impact and outlook for Croatian and EU crop and livestock markets
No full textAim of study: To investigate the impact of Croatia’s accession to the EU on its agricultural sector, its market outlook and the EU’s key agricultural products up to 2030.Area of study: Croatia and European Union member statesMaterial and methods: Comparative approach was used in order to identify similarities of the changes that took place when other Central and Eastern European Countries (CEEC) acceded to the EU (results of previously conducted research) with the changes that happened in Croatia (historical data between 2010 and 2016). The second approach involved the AGMEMOD partial equilibrium model, which has been used as a comprehensive tool to model the complex outlook of Croatian agricultural markets. The results of the Croatian outlook were compared to the EU’s AGMEMOD outlook results in order to identify future trends in key agricultural market development (production, yield and net trade) and whether these newly established trends were comparable with EU trends.Main results: The changes that took place in the Croatian agricultural sector during and after the EU accession period are not significantly different from the trends and changes observed in other Central and Eastern EU member states. Similarities can especially be found in neighbouring CEEC countries (Hungary and Slovenia), which kept their producer prices close to EU levels prior to accession. Furthermore, the results indicate a similarity with CEEC trends in terms of the strengthening of crop production compared to livestock.Research highlights: Positive effects of EU integration on the Croatian agricultural sector took place after a few years of adjustment. Simulations of future market developments indicate many similarities between Croatia and EU 13 member states