Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Integrated effect of crop sowing date and herbicide stress on fitness of Bromus diandrus Roth
Get PDFBromus diandrus Roth is a common weed species that has increased in no-tillage dry-land cereal fields in NE Spain because of the limited control options. The fitness response of plants with different emergence times (ETs) and its influence on demography has huge implications in weed management. With this subject, three ETs (F1, F2 and F3) of B. diandrus were established through three crop-sowing dates (D1, Oct.; D2, Nov.; D3, Dec.) for each of the three years in a barley-wheat-wheat rotation. In barley, the herbicides applied were not specific for B. diandrus, whereas in wheat the specific herbicide mesosulfuron-methyl plus iodosulfuron-methyl-sodium was applied. Plant density after treatments and fitness characteristics were estimated for each weed ET. Weed density decreased for later ETs and fitness was density-dependent, showing significantly higher values when a non-specific herbicide was applied, except in number of caryopses per spikelet. The increasing fitness shown by plants with later ETs and the linear relationships of vegetative biomass vs reproductive biomass and fecundity were disrupted by the herbicide mesosulfuron-methyl plus iodosulfuron-methyl-sodium. Plants that had survived this herbicide when wheat was growing had lower values for all the characteristics analysed. After three seasons, as a consequence of decreasing seed recruitment, a practical depletion of the B. diandrus population was achieved in F2 and F3 (<2.8 and <1 plants/m2, respectively) but not in F1 (60.5 plants/m2). This study shows the importance of delayed crop sowing to optimize the control of B. diandrus in cereal fields with no tillage
Methodological considerations in discriminating olive-orchard management type using olive-canopy arthropod fauna at the level of order
Get PDFThe cultivation of the olive tree (Olea europaea L.) has great importance in the entire Mediterranean basin, so that the implementation of organic practices in their management directly affects the sustainability of the agricultural system. Bioindication with arthropods can help to detect the different agricultural practices. In this work, we analyse the most appropriate methodology for discriminating between management using arthropods at the taxonomic level of order, with the novelty of taking into account the weather conditions to select the sampling dates. Between 12 and 15 sampling stations (depending on the year) were selected from olive orchards belonging to organic, conventional non-tillage, and strict conventional management, being sampled by beating the canopy fortnightly in the spring-summer period of 2007, 2008 and 2009. Organic management was more abundant and richer than the rest for the three years. Most groups with significant differences in terms of relative abundance were more abundant in organic orchard, except Neuroptera. Finally, different discriminant methods were evaluated (Linear Discriminant Analysis, Multiple Discriminant Analysis, and Support Vector Machine) with several different data sets. The discriminant analysis with interannual variability reached 97.9% accuracy in differentiating between organic and non-organic management using the LDA method, considering the taxa with significant differences from the abundance, excluding pests, and using samples with more uniform and stable weather patterns (late summer)
Effect of harvesting with a trunk shaker and an abscission chemical on fruit detachment and defoliation of citrus grown under Mediterranean conditions
Get PDFSpain ranks as the world’s leading exporter of citrus for fresh consumption. Manual harvest accounts for 50% of the total production costs. Mechanical harvest would increase labor productivity and benefits of growers. Efficiency of these machines depends on the varieties and operating conditions. Use of abscission chemicals has been promoted to increase the detachment rate of fruit without affecting its quality. This work is aimed at studying whether the mechanical harvest and/or the application of an abscission agent affect the quality and quantity of harvested fruit and tree defoliation under the conditions of citrus cultivation in Spain. Trials were made in a completely randomized experimental design. From 2008 to 2011, different orchards of mandarin and orange trees were sprayed with different doses of ethephon as abscission agent and harvested with a trunk shaker. Harvest related variables (detachment percentage, defoliation and fruit without calyx) were measured. The percentage of fruit detached by the trunk shaker ranged between 70 and 85% and it did not depend on the orchard. The shaker produced minimal damage to the bark when gripped incorrectly. Increased doses of ethephon increased fruit detachment except in ‘Clemenules’ orchard, but also increased the fruit without calyx in 1-9%. Moreover, ethephon promoted significant defoliation. Neither gummosis nor death of branches was observed. This work demonstrates that mechanical harvesting with trunk shakers may be a feasible solution for citrus cultivated in Spain for fresh market. Use of ethephon could only be recommended for citrus destined to industry and only for certain varieties
Variability, heritability and genetic association in vegetable amaranth (Amaranthus tricolor L.)
Get PDFForty three vegetable amaranth (Amaranthus tricolor L.) genotypes selected from different eco-geographic regions of Bangladesh were evaluated during 3 years (2012-2014) for genetic variability, heritability and genetic association among mineral elements and quality and agronomic traits in randomized complete block design (RCBD) with five replications. The analysis showed that vegetable amaranth is a rich source of K, Ca, Mg, proteins and dietary fibre with average values among the 43 genotypes (1.014%, 2.476%, 2.984, 1.258% and 7.81%, respectively). Six genotypes (VA13, VA14, VA16, VA18, VA26, VA27) showed a biological yield >2000 g/m2 and high mineral, protein and dietary fibre contents; eleven genotypes had high amount of minerals, protein and dietary fibre with above average biological yield; nine genotypes had below average biological yield but were rich in minerals, protein and dietary fibre. Biological yield exhibited a strong positive correlation with leaf area, shoot weight, shoot/root weight and stem base diameter. Insignificant genotypic correlation was observed among mineral, quality and agronomic traits, except K vs. Mg, protein vs. dietary fibre and stem base diameter vs. Ca. Some of these genotypes can be used for improvement of vegetable amaranth regarding mineral, protein and dietary fibre content without compromising yield loss
Characterization of a newly established aggregation of the invasive ladybeetle Harmonia axyridis and current status of the invader in Spain
Get PDFThe multicoloured Asian ladybeetle, Harmonia axyridis (Pallas), an invasive biocontrol agent introduced in North and South America, as well as in Europe for aphid control, drastically affected assemblages of native coccinellid species, local communities and people. Although the insect is common in several European countries and it was released in Spain for aphid control in 1995, no evidence of population establishment has been reported until 2011. In the present paper, 1) we summarize the records of the invasive ladybeetle in Spain and provide numerous new mentions, and 2) we follow for the first time an overwintering aggregation from autumn to spring and characterize some individual features which allow us to determine its phenology of the establishment and spreading. The results establish clearly that: 1) H. axyridis is (until now) restricted to Catalonia (NE Spain) but the invading process is in progress and the insect is able to occupy different habitats; 2) the ladybeetle overwinters successfully in Spain without significant natural mortality or parasitism; 3) the form succinea represents 73-81% of the overwintering individuals, and 4) the invasion takes probably its origin from Southern France. The potential impact of the invasion by H. axyridis in Spain is discussed
Fractional-order mathematical model of an irrigation main canal pool
Get PDFIn this paper a fractional order model for an irrigation main canal is proposed. It is based on the experiments developed in a laboratory prototype of a hydraulic canal and the application of a direct system identification methodology. The hydraulic processes that take place in this canal are equivalent to those that occur in real main irrigation canals and the results obtained here can therefore be easily extended to real canals. The accuracy of the proposed fractional order model is compared by deriving two other integer-order models of the canal of a complexity similar to that proposed here. The parameters of these three mathematical models have been identified by minimizing the Integral Square Error (ISE) performance index existing between the models and the real-time experimental data obtained from the canal prototype. A comparison of the performances of these three models shows that the fractional-order model has the lowest error and therefore the higher accuracy. Experiments showed that our model outperformed the accuracy of the integer-order models by about 25%, which is a significant improvement as regards to capturing the canal dynamics
Nitric oxide and nitrous oxide emissions from cattle-slurry and mineral fertiliser treated with nitrification inhibitor to an agricultural soil: A laboratory approach
Get PDFThe application of organic and mineral fertilisers to soil can result in increased gaseous emissions to the atmosphere such as nitric oxide (NO) and nitrous oxide (N2O) gases. The aim of this study was to evaluate under laboratory conditions the effects on mineral N dynamics and NO and N2O emissions of application to soil of cattle slurry derived liquid fraction (LF) obtained by screw press and mineral fertiliser (MF), both treated with or without the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP). An aerobic laboratory incubation was performed over 93 days with a Dystric Cambisol amended with mechanically separated LF or mineral fertiliser ammonium sulphate only or combined with DMPP. Two additional treatments were included: soil only and soil amended with DMPP. Nitrogen immobilisation was the dominant process with MF amendment, whereas N mineralisation has been observed with LF. The application of LF reduced significantly NO emissions by 80% relative to mineral but no differences were observed with N2O emissions. The addition of DMPP to MF induced a decrease of 18 and 29% in NO and N2O emissions whereas DMPP combined with LF reduced (numerically but not statistically) these emissions in 20 and 10%, respectively. Results obtained in our study suggest that N (NO + N2O) losses can be mitigated by adding DMPP to mineral fertilisers or replacing mineral fertiliser by LF
Vine vigor, yield and grape quality assessment by airborne remote sensing over three years: Analysis of unexpected relationships in cv. Tempranillo
Get PDFThe prediction of grape composition is becoming more important due to the need of reducing the current levels of alcohol and pH of the wines, a problem that is exacerbated by climate change. This work presents a 3-year study of the spatial variability of grape composition in a rainfed Tempranillo vineyard located in Rioja (Spain). It is based on the acquisition of multispectral imagery at véraison (start of the ripening process); and zoning based on NDVI, to assess its performance for zonal management. The results reveal a high spatial variability within the plot, with a stable pattern over the years, even with very different climate conditions. NDVI was a good predictor of vegetative growth variables. However, the prediction of grape composition was more complex. Unexpectedly, anthocyanins were found to be higher in the highest vigor zone, which is probably related to the effects of climate change. This unexpected relationship is particularly discussed in the article
Online laboratory evaluation of seeding-machine application by an acoustic technique
Get PDFResearchers and planter manufacturers have been working closely to develop an automated system for evaluating performance of seeding. In the present study, an innovative use of acoustic signal for laboratory evaluation of seeding-machine application is described. Seed detection technique of the proposed system was based on a rising voltage value that a microphone sensed in each impaction of seeds to a steel plate. Online determining of seed spacing was done with a script which was written in MATLAB software. To evaluate the acoustic system with desired seed spacing, a testing rig was designed. Seeds of wheat, corn and pelleted tomato were used as experimental material. Typical seed patterns were positioned manually on a belt stand with different spacing patterns. When the belt was running, the falling seeds from the end point of the belt impacted to the steel plate, and their acoustic signal was sensed by the microphone. In each impact, data was processed and spacing between the seeds was automatically obtained. Coefficient of determination of gathered data from the belt system and the corresponding seeds spacing measured with the acoustic system in all runs was about 0.98. This strong correlation indicates that the acoustic system worked well in determining the seeds spacing
Sewage sludge use in bioenergy production. A case study of its effects on soil properties under Cynara cardunculus L. cultivation
Get PDFEnergy crops cultivation is expected to further increase, which represents an opportunity to establish synergies able to enhance key environmental components (i.e. soil). To reach this benefits crop management is crucial and should be properly assessed. The aim of this work is to provide an insight on the effects of sewage sludge compost (SSC) on soil properties, when this material is applied as basal dressing for the cultivation of a Mediterranean energy crop (Cynara cardunculus L.). A 3-years trial (2008/2011) was conducted in Alicante (Southeastern Spain), testing four SSC application rates (0, 30, 50 and 70 t/ha) on a heavy textured Anthrosol. The addition of SSC enhanced soil fertility, primarily increasing organic carbon (Cox), Kjeldahl nitrogen (Nk), available P (PBurriel), CuDTPA and ZnDTPA levels. Comparatively with the control (0 t/ha), 30, 50 and 70 t/ha treatments induced a rise of 11%, 19% and 25% in Nk (Control=1.11 g/kg) and PBurriel (Control=79 mg/kg), while for Cox (Control=11.8 g/kg) was 14%, 21% and 30%. However, these variables apparently did not significantly decrease throughout the experiment, which suggests that the organic matter added was under a stabilization process, favoured by the poor physical properties of the soil. Other elements (NaNH4Ac, KNH4Ac, MnDTPA) were accumulated within the soil as time passed by, as a result of soil status, Mediterranean environmental conditions and crop management. The use of SSC as organic fertilizer represents an effective option to optimize cynara cultivation systems while improving soil quality through enhanced long-lasting organic matter pools