Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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A quantitative study of pollarding process in silvopastoral systems of Northern Zagros, Iran
Get PDFAim of study: This research attempts to quantitatively describe the pollarding process in the northern Zagros, western Iran.Material and methods: An inventory of all trees was conducted in three representative stands in the pollarded section (DBH ≥ 5 cm): DBH, total height, trunk height and crown diameters were measured. At the time of pollarding, 10% of the foliage stacks were randomly selected and weighed. The positions of each store tree (i.e. special trees capable of enduring the weight of a certain number of leafy branches (average 600 kg)) and horizontal distance of pollarded trees associated with each store tree was recorded.Main results: The number and weight of foliage stacks resulting from pollarding of each tree correlated (0.48 and 0.43, respectively) with their crown diameter. The average dry weight of leaf biomass was 1,525.6 ±108.1 kg/ha and there was a significant difference between the selected stands. The average pollarded area and the average number of trees in the pollarded area of each store tree was 501.1±210.4 m2 and 9.4±3.5 trees, respectively.Research highlights: The number of pollarded trees associated with each store tree and the weight of stored foliage stacks on them are determined by the distance between pollarded trees and store trees, the number of trees around the store trees and the ability of selected store trees to bear the weight of foliage stacks
Dry weight loss in leaves of dominant species in a successional sequence of the Mesopotamian Espinal (Argentina)
Get PDFAim of study: To compare litter decomposition dynamics among different species within a single forest type and also between a single species in different forest successional stages.Area of study: Different forests of a known successional sequence of the Mesopotamian Espinal, placed in Villaguay Department, Entre Ríos Province, Argentina.Material and methods: A standard “litter bags” technique was employed. Chemical analyses of C and N were performed for leaves. A regression analysis was applied and data were fitted to a double exponential model. Means estimated among forests and species within each forest were compared using the Tukey-Kramer test.Main results: The model predicted that leaves would completely mineralize in the mid-term. Leaf decomposition rate in different species (both in the Secondary forest and Mature forest) had dry matter residues in the following decreasing order: Acacia caven > Prosopis nigra > Prosopis affinis > Celtis ehrenbergiana. Research highlights: Successional stage was not found to be a factor determining the decomposition rate among species. Different decomposition rates, observed among different species, would not be attributed to initial quality of residues in terms of C and N, but would be associated with a positive feedback process related to nutrient cycle; thus, a greater decomposition would increase nutrient availability and, consequently, litterfall input
Are clearcut borders an effective tool for Scots pine (Pinus sylvestris L.) natural regeneration?
Get PDFAim of the study: To describe the effect of stand edge after clearcut on the process of Scots pine (Pinus sylvestris L.) natural regeneration along the edge-to-interior gradient. The density, height, horizontal structure and quality of natural regeneration was evaluated.Area of the study: Kokořínsko Protected Landscape Area, Northern Bohemia (Czech Republic). The study sites naturally host Scots pine Pinetum oligotrophicum with cover of Vaccinium myrtillus L. and Vaccinium vitis-idaea L. in the herbal storey.Material and methods: Two 40 × 40 m permanent research plots were situated at the forest edge, two adjacent plots were established within the forest stand as control plots. Differences in regeneration characteristics were tested by analysis of variance (ANOVA) followed by the Tukey HSD test. Interactions between regeneration characteristics and the distance from the edge were evaluated by Pearson correlation. The relationship between the top storey and natural regeneration was depicted by pair-correlation function. Principal components analysis was carried out to assess overall data structure.Main results: Generally, the further from the stand edge, the lower natural regeneration density (r ≤ -0.64, p<0.001), mean height (r ≤ -0.54, p<0.001) and the best-quality promising individuals (r = -0.40, p<0.05) were found, whereas significant influence on overall average pine quality was not observed. The highest regeneration density (15,250 pcs/ha) was reached at a distance of 5-10 m from the stand edge.Research highlights: The forest edge interior can become favourable location for natural regeneration and can be implemented into traditional regeneration approaches in pine regions
Cost evaluation of three ground-logging methods in a mixed broadleaved mountainous forest
Get PDFAim of study: To compare cost and productivity of three ground-based logging methods by skidder: 1, tree length method (TLM), 2, long length method (LLM) and 3, short length method (SLM).Area of study: A mixed broadleaved mountainous forest stand in the Hyrcanian forests in northern Iran.Material and methods: To develop time prediction models, all measurements of time were replaced by their decadic logarithms, and on the basis of the developed models, we simulated cost of 11 skidding turns depending on the diameter of the log (DL), skidding distance (SD), and the winching distance (WD) for TLM, LLM, and SLM.Main results: Our results demonstrated that on average the net costs per extraction of one cubic meter wood (m3) were 3.06, 5.69, and 6.81 €/m3 in TLM, LLM, and SLM, respectively, and the most economical alternative depending on DL, SD and WD was a TLM. Furthermore, the results of simulated models suggest that as long as the diameter of the felled trees is less than 40 cm, the cut-to-length system is not an economical alternative. The cut-to-length method can be applied for trees with larger diameter (more than 40 cm), and in short skidding distance SLM is preferable to LLM but in cases of long skidding distance, LLM is more economical than SLM.Research highlights: DLand SD were the main causes which influenced the productivity and cost of ground-based logging methods
Gmelina arborea “death disease” in fast-growth plantations: Effects of soil and climatic conditions on severity and incidence and its implications for wood quality
Get PDFAim of study: Plantations are threatened by an emerging disease called “Gmelina death disease”. The objective of this study was measured the incidence and severity of this disease and were correlated with the characteristics of the plantations, micro- and macronutrients in the soil and climatic parameters.Area of study: The present study evaluated 16 symptomatic fast-growth plantations of different age in Costa RicaMaterial and methods: Fungi were identified from xylem of infected trees. Incidence and severity was measured and correlated with the characteristics of the plantations, micro- and macronutrients in the soil and climatic parameters. Root condition and the quality (specify gravity, mechanical and decay resistance and chemical compositions), of the wood of symptomatic and asymptomatic trees were compared.Main results: Three fungal species (Chaetomella raphigera, Fusarium solani and Rhizomucor variabilis) were identified from diseased samples. Clay content in the soil profile from 10-20 cm deep explained a significant proportion of the variation in the incidence and severity of the disease, and stand density was related to severity. Although two climatic variables, Holdridge’s potential annual evapotranspiration and Thornthwaite’s potential evapotranspiration, showed a relationship between the incidence in the trees and symptoms of the disease. Infected wood turned black in symptomatic trees. Specify gravity and mechanical resistance of infected wood decreased, whereas its natural durability was unaffected. Changes were observed in the quantities of Mg, Fe, Ca, K and Zn in infected wood.Research highlights: Gmelina plantations established in sites with high stand densities and high contents of clay increase susceptibility to this disease
Possible origin of Triticum petropavlovskyi based on cytological analyses of crosses between T. petropavlovskyi and tetraploid, hexaploid, and synthetic hexaploid (SHW-DPW) wheat accessions
Get PDFIntraspecific hybridization between Triticum petropavlovskyi Udacz. et Migusch., synthetic hexaploid wheat (SHW-DPW), and tetraploid and hexaploid wheat, was performed to collect data on seed set, fertility of F1 hybrid, and meiotic pairing configuration, aiming to evaluate the possible origin of T. petropavlovskyi. Our data showed that (1) seed set of crosses T. petropavlovskyi × T. polonicum and T. petropavlovskyi × T. aestivum cv. Chinese Spring was significantly high; (2) fertility of hybrids T. petropavlovskyi × T. polonicum and T. petropavlovskyi × T. aestivum ssp. yunnanense was higher than that of the other hybrids; (3) fertility of F1 hybrids SHW-DPW × T. dicoccoides and SHW-DPW×T. aestivum ssp. tibetanum was significantly high; and (4) c-value of T. petropavlovskyi × T. polonicum and T. petropavlovskyi × T. aestivum cv. Changning white wheat was also significantly high. The results indicate that the probable origin of T. petropavlovskyi is divergence from a natural cross between T. aestivum and T. polonicum, via either spontaneous introgression or breeding effort
Innovation behaviour and the use of research and extension services in small-scale agricultural holdings
Get PDFFarmers’ views on research and extension services (RES) included in the Agricultural Knowledge and Innovation System are rarely investigated. This study analyses the relationship between key factors of innovation behaviour (market orientation, learning orientation, and innovation attitude) and the use of RES through structural equation modelling, focusing on small-scale agricultural holdings. Market orientation and learning orientation appear to be positively correlated, confirming that synergies between both factors provide a background for innovativeness. Learning orientation and farm-holders’ education level, improve knowledge exchange and make the agriculture innovation process more inclusive. However, farmers’ innovation attitude is not clearly correlated with the use of RES. Motivations about “the will to do innovations” are represented by a construct that does not appear to have a determinant effect as a mediator in farmer’s decisions about using RES
A comparative analysis of genetic diversity in Portuguese grape germplasm from ampelographic collections fit for quality wine production
Get PDFGrapevine cultivars diversity is vast and full of synonyms and homonyms. Up to few decades ago characterization of grapevine was based on morphological characters. In the last decades, molecular markers were developed and have been used as tools to study genetic diversity in a range of different plant species. Fifty-six Portuguese accessions representative of ‘Vinhos Verdes’ and ‘Douro’ Controlled Designations of Origin (DOC) were analysed through DNA fingerprints generated by Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeat (ISSR). The study aimed to compare the effectiveness of RAPD and ISSR molecular techniques in the detection of synonyms, homonyms and misnames. RAPD and ISSR analysis enabled the detection of 36 different band patterns, reducing in about 36% the initial material. Several accessions grown under different names, between and within collections, were confirmed as the same genotype, namely Gouveio/Verdelho, Sousão Douro/Vinhão and Arinto Oeste/Pedernã. Similarly, some homonyms/misnames were also identified, namely within Azal Tinto and Rabigato accessions. RAPD and ISSR markers revealed to be adequate molecular techniques for grapevine varieties fingerprinting with advantages over other molecular procedures, contributing for a good management of grapevine collections