Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Use of root pruning, paclobutrazol, and prohexadione-Ca combination strategies to control growth and improve productivity on pear trees
Get PDFGrowth control in pear orchards is essential, not just to reduce competition between vegetative and reproductive sinks, but also to improve return bloom, yield and fruit quality. The goal to optimize growth control, return bloom and yield must be pursued with the integration or combination of several strategies. Aim of this study was to assess the use of root pruning, paclobutrazol, and prohexadione-Ca (ProCa) either alone or in combination, to control growth and improve productivity on pear trees. The experiment was conducted during three years in a 10 year-old pear orchard with ‘Blanquilla’ as the scion cultivar. All of the different strategies that were assessed improved growth control in pear trees, with different grade depending on the strategy. Control trees had about 50% of the shoots shorter than 60 cm, root pruning 63%, ProCa 70%, paclobutrazol and root pruning plus ProCa 83%, and root pruning plus paclobutrazol 86%. In addition, yield, fruit weight and return bloom were more affected by applications of ProCa than paclobutrazol. Use of paclobutrazol either alone or in combination with root pruning seems to be most suitable for situations of high-vigor cultivars. The fact that use of paclobutrazol may be challenged again in the future, leave combinations of root pruning plus ProCa as the best shot for vigorous cultivars. In other situations of medium-low vigor, ProCa alone would be the best strategy
An artificial neural network model to predict the effective work time of different agricultural field shapes
Get PDFThe aim of this study was to find a model able to extract the net time per unit of net worked area from different agricultural field basic shapes (square, circle, rectangle and triangle) considering the following variables: field gross area, working speed, number of turnings (these depending on the effective working width), side length parallel and orthogonal to working direction, and working direction type. Being this a non-linear problem, an approach based on artificial neural networks is proposed. The model was trained using an artificial dataset calculated for the various shapes (internal test) and then tested on 47 different agricultural operations extracted by a real field dataset for the estimation of the net time (external test). The net time records obtained from both, the trained model and the external test, were correlated and the performance parameter r was extracted. Both regression coefficients (r), for the training and internal test, appear to be excellent being equal to 0.98 with respect to traditional linear approach (0.13). The variable “number of turnings” scored the highest impact, with a value equal to 44.34% for the net time estimation. Finally, the r correlation parameter for the external test resulted to be very high (0.80). This information is very valuable of the use of information management system for precision agriculture
Analysis of forest wood supply chains for round-wood production restricted by technical constraints
Get PDFAim of the study: Integrated information tools models are fundamental for analyzing supply chains as regards pattern of consumption and production. These models are very useful for availability estimations of natural resources when social and environmental uncertainties need to be addressed, as it is the case for forest wood supply chains. This work presents an analysis of a forest wood supply chain focusing on forest operations to estimate the availability of round-wood volume restricted by technical constraints using a local case study in Mexico. The theoretical and technical potentials of woody biomass availability were reviewed considering an assessment of forest operations for round-wood production.Area of the study: municipality of Santa Maria del Rio S.L.P. inside the forested land of San Antonio in Mexico.Material and methods: Geographical, historical and socioeconomic data and field work were used to develop technical constraints as extraction limits. Felling and extraction operations were analyzed resulting in a production rate of 2.48 m3 per productive machine hour.Main results: The theoretically produced standing timber accounted to 21,132 m3. After simulating technical constraints, the technically feasible supply of round-wood accounted to 2, 113 m3. Furthermore, a biomass flow chart for tracing biomass along the system boundaries was developed.Research highlights: With the given results, it is possible to give recommendations and conclusions for the improvement of wood supply chains supported by time studies values, technical constraints on terrain slope, harvesting intensity and mechanization level.Keywords: Mexico; modeling; forest operations; sustainable forest management
Ovule senescence and unusual pollen tube growth in the ovary of sweet cherry as affected by pistilar genotype and temperature
Get PDFThe study of ovule senescence in the ovaries of four sweet cherry cultivars (‘Karina᾿, ‘Kordia᾿, ‘Regina᾿ and ‘Summit᾿) in the environmental conditions of West Serbia was carried out. Monitoring of ovaries was performed using the fluorescence microscopy method, on emasculated and pollinated flowers (cross-pollination variant), non-emasculated open-pollinated flowers (open pollination variant), and emasculated unpollinated flowers (unpollinated variant). In cross- and open pollination variants, the rate of unusual pollen tube growth in the ovary, fertilization percentage and fruit set were determined. The tendency in the appearance of fluorescence, as an indicator of ovule senescence, showed strong genotypic dependence ‒ it was the most and the least pronounced in the ovaries of ‘Kordia’ and ‘Regina’, respectively, in all the flower categories. Investigation of unusual pollen tube growth, fertilization percentage and fruit set, considered from the aspect of ovule senescence and cultivars’ behaviour as female (pollinated), pointed to their specific relations and complex dependence on the air temperature before and during the flowering. Flower emasculation and pollination also influenced ovule senescence, and this impact was unequal by genotypes, i.e. those having better ovule vitality in general, had also better ovule vitality in the conditions of emasculation, and pollination absence. The results imply different adaptation of cultivars to higher temperatures before and during the flowering, pointing to the further investigation related to the good adaptability of genotypes to air temperatures in reproductive sense, which is a basic indicator of good adaptability in general
Foraging behaviour and performance of steers from two local breeds (Asturian Valley and Asturian Mountain) grazing in Cantabrian (N Spain) summer pastures
Get PDFSteer meat production in northern Spain is deficient to attend market demand. This research aimed to compare the foraging behaviour and production of yearling steers from two local breeds differing in body weight (BW), Asturian Valley (AV, 372 kg) and Asturian Mountain (AM, 307 kg), grazing in summer pastures consisting of 70% grassland and 30% heathland. Bodyweight gains from a total of 42 steers were recorded during four grazing seasons (from June to October). In two years, in July and September, plant community selection and diet composition were estimated by direct observation and using faecal markers, respectively. Grazing time increased from July to September (488 vs. 557 min/day; p<0.001) as sward height in the grassland decreased. Although AV steers grazed proportionally for longer on herbaceous pastures than AM steers (81.3 vs. 73.3%; p<0.05), no differences between breeds were found in diet composition. AM steers showed greater mean daily BW gains than AV steers (252 vs. 133 g/day; p<0.01). From June to August, steers from both breeds gained BW (487 vs. 360 g/day for AM and AV, respectively; p<0.01), but thereafter BW gains decreased (120 vs. –12 g/day for AM and AV, respectively; p<0.05), because of reduced availability of grassland herbage. Yearling steers from AM breed seem to be better suited to mountain conditions than those from AV breed, probably because of their smaller body size and lower total nutrient requirements for maintenance
Effect of growth hormone on milk yield and reproductive performance of subfertile Holstein cows during extended lactations
Get PDFThe objective of this study was to determine the effects of the administration of recombinant bovine somatotropin (rbST) throughout lactation to high-yielding subfertile (conception > 270 days postpartum) Holstein cows undergoing extended lactations (≥480 d) on milk production and reproductive performance. The study used two large adjacent commercial herds with similar management in a hot area of northern Mexico (25° N). Cows in one herd (n=2341) received a 500-mg dose of rbST every 14 d until dried off, starting 60 days postpartum. The other herd served as control (n=984). Across parity, rbST-treated cows produced 20% greater milk yield than control cows in 305-d lactations. Across parities, milk yield from 305 d postpartum to the end of lactation was 2734 kg higher in rbST-treated cows than control cows. Across parities rbST-treated cows produced 4777 more kg of milk during the entire lactation (mean 605 d) than the control group (mean 572 d). Conception rates (CR) at first service were only 3.2% and 5.9% (p<0.05) for control and rbST-treated cows, respectively. Overall CR was 43.5% and 61.6% (p<0.05) for control and treated cows, respectively. Control cows required 2.4 more (p<0.01) services per conception than rbST-treated cows. It was concluded that in this hot environment, the use of rbST suits dairy producers because it substantially improves both milk yield and reproductive performance in subfertile high-yielding Holstein cows. By markedly increasing lactation length and lactation persistency farm efficiency is greatly improved due to extended herd life
Susceptibility of non-cereal crops to Fusarium graminearum complex and their role within cereal crop rotation as a source of inoculum for Fusarium head blight
Get PDFFusarium graminearum, the cause of Fusarium head blight (FHB), is an important cereal pathogen. Moreover, some non-graminaceous crops are also known to be susceptible to F. graminearum infection. This study assessed the presence of F. graminearum species complex on non-cereal plants, grown in a cereal crop rotation and evaluated its pathogenicity to non-cereal plants in vitro and to spring wheat under field conditions. The relative density of Fusarium species isolated from oilseed rape, pea, potato and sugar beet plants was assessed in 2015 and 2016. A total of 403 isolates of Fusarium spp. were obtained from non-cereal plants and only 5% of the isolates were identified as F. graminearum. The pathogenicity test revealed that isolates of F. graminearum from spring wheat and non-cereal plants caused discolourations on leaves of faba bean, fodder beet, oilseed rape, pea, potato and sugar beet. The pea was the crop most susceptible to F. graminearum isolated from spring wheat. The pathogenicity of F. graminearum from sugar beet, oilseed rape, pea and potato to the same hosts differed depending on isolate and inoculated plant. Under field conditions, F. graminearum isolates from pea, potato, oilseed rape and wild viola were able to cause typical FHB symptoms in spring wheat. Based on the information generated in this study, we conclude that under congenial conditions, growing faba bean, pea, sugar beet, fodder beet, oilseed rape and potato plants in a cereal crop rotation may serve as alternative or reservoir hosts for F. graminearum pathogens
Whole-grain cereal voluntary intake and preference in Japanese quail (Coturnix coturnix japonica)
Get PDFJapanese quail (Coturnix coturnix japonica) usually fed on ground or pelleted balanced feeds, while whole grains are supplied in alternative systems. Voluntary intake and preference of four whole-grain cereals (durum wheat, bread wheat, triticale and barley) were assessed in Japanese quails. Two experiments were performed: (i) a trial with five batches of six randomly selected quails (three males, three females) allocated to each treatment consisting of one cereal or a balanced feed (control) in the voluntary intake experiment; and (ii) a trial with four bird batches receiving simultaneously the four cereals in the preference experiment. Three repetitions of each trial were performed. When feedstuffs were provided as a sole feed, voluntary feed intake differed, being the highest in quails fed the balanced feed (20.0 g/d), intermediate for durum wheat (15.0 g/d), bread wheat (15.8 g/d) or triticale (15.6 g/d), and the lowest for barley (12.1 g/d). Voluntary intake did not differ between sexes. Positive correlations existed between voluntary feed intake and live weight of quails, being the highest and very strong for the balanced feed, moderate for durum and bread wheat and barley, and weak for triticale. The preference trial showed that quails preferred durum wheat (7.1 g/d), triticale (4.0 g/d), bread wheat (3.0 g/d) and barley (0.3 g/d) in descending order, independently of sex. Positive correlations existed between daily feed intake and live weight of birds for durum and bread wheat. Strong positive correlation existed between bird live weight and total intake when the four cereals were available simultaneously. Differences in voluntary intake and preference among whole-grain cereals should be take into account when used to feed quails
Dynamic of Brassicogethes aeneus (F.) (Coleoptera, Nitidulidae) populations in Serbia’s downriver Danube section and their susceptibility to insecticides
Get PDFThis paper presents data on the dynamic of B. aeneus populations in winter oilseed rape in the downriver section of the Danube in Serbia, which were acquired by yellow water traps and a beating method. Their susceptibility to several insecticides of different classes (organophosphates, pyrethroids and neonicotinoids) (adult vial test and dipping test) was tested over two seasons (2009 and 2010). B. aeneus populations developing under the agroecological conditions that exist in Serbia were monitored to detect the moment of OSR infestation during its sensitive growth stages. Adults were counted, and the data revealed that they infest winter OSR crops during the stem elongation growth stage (BBCH 30-31), reaching a population peak at the green-yellow bud stage (BBCH 57-59), and exceeding the economic threshold, while the populations decreased substantially during the subsequent stage (BBCH 61-69). Laboratory test results did not confirm any changes in B. aeneus susceptibility/resistance to pyrethroid, organophosphate and neonicotinoid insecticides. Migration of B. aeneus populations was monitored as a way of developing predictive models for estimation of infestation severity and the timing of pest outbreaks under agroecological conditions existing in Serbia. As resistance to pyrethroids has been confirmed in B. aeneus populations in many European countries, their susceptibility will be further monitored
Predicting spring wheat yields based on water use-yield production function in a semi-arid climate
Get PDFGrain yield of spring wheat (Triticum aestivum L.) fluctuates greatly in Western Loess Plateau of China due to limited and highly variable precipitation. Farmers in this area need a simple tool to predict spring wheat grain yield and assess yield loss risk efficiently. The objectives of this study were to establish relations between water use and grain yield of spring wheat for predicting actual yield and attainable yield (water limited yield) under conventional management practice and mulching practices. Reference data during 1993-2013 and field experiment conducted from 1987 to 2011 were used to determine water use-yield production function and boundary function for spring wheat. Probability of achieving a given spring wheat grain yield threshold is determined based on available soil water content at sowing plus expected precipitation during growing season. Single linear equation was obtained with slope of 14.6 kg ha-1 mm-1 and x intercept at 126.3 mm for spring wheat water use-yield production function with different wheat varieties under varying climatic patterns. The slopes of the boundary function were 16.2 kg ha-1 mm-1 and 19.1 kg ha-1 mm-1 under conventional management practice and mulching practices, respectively. With increase of available soil water content at sowing, the probability of achieving at least 2000 and 4000 kg ha-1 of spring wheat for actual and attainable yield increased under different agricultural management practices