Please login first

List of accepted submissions

Show results per page
Find papers
  • Open access
  • 80 Reads
Monitoring of a calcium biofortification workflow for tubers of Solanum Tuberosum L. cv. Picasso using smart farming technology

Due to the rapid growth of the population worldwide and the need of providing food safety in large crop productions, UAVs (Unmanned Aerial Vehicles) are being used in agriculture to provide valuable data for decision making. Accordingly, through precision agriculture, an efficient management of resources, using data obtained by the technologies, is possible. Considering that through remote sensed data collected in a crop region, it is possible to create NDVI (Normalized Difference Vegetation Index) maps, which are a powerful tool to detect, namely stresses in plants, this study aimed to access the impact of Ca biofortification process in leaves of Solanum tuberosum L. cv. Picasso. As such, using as a test system, an experimental production field of potato tubers (GPS coordinates - 39º 16’ 38,816’’ N; 9º 15’ 9,128’’W), plants were submitted to a Ca biofortification workflow through foliar spraying with CaCl2 or, alternatively, chelated calcium (Ca EDTA) at concentrations of 12 and 24 kg ha−1. It was found a lower average of NDVI in Ca(EDTA) 12 kg ha-1 treatment after the 4th foliar application, which through the application of the CieLab scale correlated with showed a lower L (darker color) and hue parameters, regarding the remaining treatments. Additionally, a higher Ca content was quantified in the leaves. The obtained data is discussed to conclude that Ca(EDTA) 12 kg ha-1 triggers a lower vigor in Picasso potatoes leaves.

  • Open access
  • 67 Reads
Monitoring a calcium biofortification workflow in an orchard of Pyrus communis var. Rocha applying precision agriculture technology

Smart farming techniques can be used to maximize food production. This can be achieved by rapid detection of variations in crops and clever use of resources such as water and fertilizers, which might minimize crop stress through direct target practices. In an orchard located in the West region of Portugal (GPS coordinates 39°23’28.997’’N; 9°4’52.483’’W), a Ca biofortification workflow with 7 foliar sprays of CaCl2 (4 kg.ha-1 and 8 kg.ha-1) was used to increase Ca contents in “Rocha” pear trees. During the biofortification process, an Unmanned Aerial Vehicle synchronized by GPS, was used to characterize the orchard regarding it`s morphology (slope) and to monitor trees (NDVI - Normalized Difference Vegetation Index). These data were correlated with Ca content (assessed by X-Ray fluorescence analysis) and photoassimilates synthesis (assessed by leaf gas exchange measurements). The orchard showed no major slopes and after 4 sprays with CaCl2, NDVI values revealed no major differences between the control and sprayed trees. Accordingly, leaf gas exchange parameters did not reveal negative impacts in the photoassimilates synthesis of the sprayed trees, although in the leaves Ca content significantly increased. The use of precision agriculture techniques in correlation to other analysis to assess plant stress is discussed.

  • Open access
  • 65 Reads
Can precision agriculture be used in the management of a Fe and Zn biofortification workflow in organic tomatoes (Lycopersicum esculentum L.)?

Is expected that the population worldwide might reach 9.15 billion by 2050, being therefore imperative to increase food production. As such, the development of smart farming technology is an important key food production issue. In fact, through the use of UAVs (unmanned aerial vehicles), it’s possible to create normalized difference vegetation index (NDVI) maps, that can indicate, namely, health and vegetation vigor. In this context, this study aimed to assess the state of three tomato varieties (beef heart, “chucha” and apple) in the framework of a biofortification workflow with Fe and Zn, following an organic production mode. In a tomato experimental production field (GPS coordinates - 39° 41’ 48,517’’ N; 8°35’ 45,524’’W), six foliar applications were carried out during the production cycle, with a mix of Zitrilon (15%) (0.40 and 1.20 kg.ha-1) and Maxiblend (1 and 4 kg.ha-1). NDVI was determined (after the 2nd foliar application) and showed a maximum of 0.86 (on a scale from -1 to 1), whereas the color of leaves (using the CieLab scale) varied significantly, after the 3rd foliar application. Moreover, in freshly harvest tomatoes (assessed through spectrophotometric colorimeter) no changes were detected, but an increase of Fe and Zn content was found in the leaves and of Zn in tomatoes (except in “chucha” variety). The use of precision agriculture techniques in correlation with the other analysis is discussed.

  • Open access
  • 174 Reads
A case study about the use of precision agriculture technology applied to a Zn biofortification workflow for grapevine Vitis Vinifera cv Moscatel

The human population is growing worldwide which increases the food demand. Following this assumption, strategies to enhance the food production are being explored, namely smart farming for monitoring crops during the production cycle. In the present study, a vineyard Vitis Vinifera cv. Moscatel located in Palmela (N 38º 35’ 47.113’’ O 8º 40’ 46.651) was submitted to Zn biofortification workflow through foliar application of zinc oxide (ZnO) or zinc sulfate (ZnSO4) (respectively, at a concentration of 60% and 90% - 900g.ha-1 and 1350g.ha-1). The analysis of the field morphology and vigor of the vineyard was performed through Unmanned Aerial Vehicles (UAV’s) images (assessed with altimetric measurement sensors), synchronized by GPS. Drainage capacity and slopes showed 1/3 of the field with reduced surface drainage and a maximum variation of 0.80 m between the extremes (almost flat) respectively. The NDVI (Normalized Difference Vegetation Index) values reflected a greater vigor in treated grapes with treatment OZn90 showing a higher value. This data were interpolated with mineral content, monitored with X-Ray fluorescence analysis (showing a 1.3 fold increase for the biofortification index). Data is discussed being concluded that the used technologies furnishes target information in real time about the crops production.

  • Open access
  • 70 Reads
Application of anti-transpirant based on di-1-p-menthene to improve the growth of young olive trees

The olive tree undergoes significant stress with high temperatures and irradiance levels occur during the growing season. Various products are used to ameliorate the negative effects of abiotic stress in plants, aiming at different physiological, biochemical and morfological functions such as the use of plant products that attracte considerable interest from the scientific community and commercial enterprises. Many products of biological origin have significant potential for improving physiological processes in plants and stimulating germination, growth and stress tolerance.

The aim of the research was to examine the effects of a plant-derived anti-transpirant (Vapor Gard®, VG) on the growth of 2 years old olive trees subjected to high temperature in nursery. Vapor Gard® is a water emulsifiable organic concentrate of di-1-p-menthene (C20H34), a terpenic polymer also known as pinolene. The study was carried out in greenhouse on trees of native cultivar of Campania (cv Salella) grown in pot, during the growing season from may to september 2020. The experimental design included anti-transpirant product (VG) applied 5 times at 20 days intervals compared with a Control, each thesis, consisting of 10 trees. On trees was evaluated: stomatal conductance, chlorophyll a fluorescence, SPAD index, RWC, growth of shoots, total leaf area per plant, trunk croos-sectional area and dry matter partitioning.

The results obtained show that applications of di-1-p-menthene are able to induce a significant improve of the shoots growth (+25.1 %) and trunk croos-sectional area (27.07 vs 39.18 mm2). At same time a significant reduce of the stomatal conductance and an increase of leaf RWC values were recorded. The treatment with the anti-transpirant also favored the increase of SPAD values of leaves (+4.4 %). At the end of the experiment the treated trees had greater total dry matter than the control (+10.8 %).

  • Open access
  • 74 Reads
Application of Multispectral Images to Monitor the Productive Cicle of Vines Fortified with Zinc

In a context of an exponential growing population and resource limitations, precision agriculture techniques can improve efficiency in the agricultural sector. This can be achieved by monitorization and quick detection of changes in crops, resulting in smart resource use, waste reduction and maximization of production. In a field located in Palmela (Portugal), three foliar sprays of ZnO and ZnSO4 were performed in Vitis Vinifera variety Fernão Pires for production of biofortified single-vine wine. Field characterization was performed with soil sampling and UAVs (with altimetric measurement sensors), synchronized by GPS. Vegetations indexes, and characterization of drainage capacity and slopes were then interpolated with mineral content, monitored with X-Ray Fluorescence analysis. Morphologically, the experimental parcel had a slight slope (maximum of 1.10m) with irrigation and nutrient availability in soil requiring special attention (i.e., just 1/3 of the parcel a higher capacity to water drainage). NDVI values reflected better physiological values in N-NE region. Zinc increases in leaf’s were directly proportional with applied concentrations and vines sprayed with ZnO revealed greater vigor than ZnSO4. In conclusion, the use of precision agriculture techniques and its crossing with other analysis, allow the characterization and monitoring of vines, presenting a major potential for optimization of wine production.

  • Open access
  • 70 Reads
Durum wheat yield and N uptake as affected by N rate, timing and N form in Mediterranean environments.

In Nitrate Vulnerable Zones (NVZ) site-specific techniques are needed to match N availability with durum wheat (Triticum turgidum subsp. durum Desf.) requirements.

Slow-release fertilizers can improve efficient N supply and reduce leaching, thus contributing to sustainable agriculture.

To study the effects of rates, sources and timings of nitrogen application, two-year field experiments were carried out in two Mediterranean NVZs of Central Italy (Pisa and Arezzo).

The trial compared: i) two N rates: one based on the crop N requirements (NO), the other on the Action Programmes’ prescriptions of the two NVZ (NAP); ii) three N sources: urea, methylene urea, and nitrification inhibitor DMPP; iii) two top-dressing times: BBCH21 and BBCH31.

Grain yield, yield components were determined, together with N uptake.

Results showed that: i) grain and biomass production were reduced with NAP at both locations; ii) urea performed better than slow-release fertilizers; iii) the best application time varied depending on the N source, as slow release fertilizers achieved higher yield when applied earliest (BBCH21) at both locations, while urea performances differed between locations (BBCH31 was better at Pisa and at BBCH21 at Arezzo).

Different behaviors of top-dressing fertilizers at the two localities could be related to the diverse patterns of temperatures and rainfall. Therefore, optimal fertilization strategies vary according to environmental conditions.

  • Open access
  • 70 Reads
Response of wheat plants with different allele status of gene Gpc-B1 on zinc deficiency
, , , ,

The problem of improving the wheat grain quality is currently relevant all over the world, and as a result, a search for methods is being carried out to eliminate it. It is proposed to use the method of distant hybridization for this purpose, but there are few experimental data confirming this possibility. But it is known that with the introduction of a functional Gpc-B1 allele from wild wheat (Triticum dicoccoides) into varieties of common wheat (T.aestivum), the protein and some micronutrients content, including zinc, increases in the grain. It is believed that this effect is associated with the participation of Gpc-B1 in more efficient zinc remobilization in the plant. Therefore, it can be assumed that plants with a functional Gpc-B1 allele will be more resistant to zinc deficiency. However, there is practically no such data. We studied the effect of zinc deficiency on the flag leaf area, chlorophylls content in it, spike size and grains number in wheat plants that differ in the allele status of gene Gpc-B1. The objects were T.dicoccoides (functional allele – f.a.), T.aestivum cv.Festivalnaya (non-functional allele – n-f.a.), and two lines isolated in the offspring from crossing cv.Festivalnaya with T.dicoccoides: line 15-7-1 (f.a.) and line 15-7-2 (n-f.a.). The plants were grown in pots with sand. Control plants grew at the optimum zinc concentration; in the experimental variants, zinc was not added to the substrate.

The studies carried out revealed a inhibitory effect of zinc deficiency on the flag leaf growth of only line 15-7-2. In cv.Festivalnaya plants no significant differences from the control were observed. In contrast, in T.dicoccoides and line 15-7-1, the flag leaf area was higher than the control. In addition, in these plants under zinc deficiency, a high chlorophylls content remained, while in plants with a n-f.a., it significantly decreased. It was also found that in line 15-7-2 under zinc deficiency the spike length and the number of formed grains decreased.

The results show that the presence of a functional Gpc-B1 allele in T.aestivum promotes better plant adaptation to zinc deficiency and the maintenance of high seed productivity. This confirms the promise of using the remote hybridization method to create wheat lines with high grain yields in deficiency of this micronutrient.

The work was supported by RFBR (project No 20-516-00016), BRFBR (project No Б20Р-240) and under state order (No. 0218-2019-0074).

  • Open access
  • 146 Reads
Metagenomic and culturomic approaches for blueberry biofertilizer design

Some decade ago, the blueberry (Vaccinium myrtillus) crop has been introduced in Portugal, and nowadays is widespread along the North and Center of Portugal. It has a great relevance as exportation product, taking advantage of the climatic conditions they allow to produce when the market does not have entrances from the producing countries of Northern Europe. However, it is this climate condition that could create problems in the near future since, if climate change models are correct, an increase in temperature and a reduction in precipitation will happen. In this work, we study the rhizospheric and endophytic population of wild blueberry plants in three locations of mainland Portugal intending to determine the core bacterial populations of these plants in Portugal to design new biofertilizers to improve the adaptation of this crop. The metagenomic approach revealed that the rhizospheric populations are influenced by temperature and climate, but the endophytic populations of Vaccinium are modulated by the plant. From this plant s total of 318 bacterial strains were isolated and their Infraspecific diversity has been analysed using RAPD-M13, obtaining 66 different fingerprints, which were identified employing MALDI-TOF MS methodology and a comparison against the MALDI Biotyper 3.0 database. A 64% of the strains were identified at genus level and the remaining ones by 16S rRNA sequencing. Bacillus, Rhizobium, Serratia, Steptomyces, Paenibacillus, Pantoea, or Pseudomonas were some of the identified genera. Most strains were able to grow at pH 5.5, in presence of 2% NaCl and were psychoresistant. Plant growth promotion potential of these strains was analysed revealing that most of the isolates were capable of solubilizing dicalcium phosphate and only 17% of the isolates produced siderophores.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 101003373.

  • Open access
  • 73 Reads
Considering clodiness in estimating soil rooting capacity and fertility

The estimate of soil fertility, namely, water and nutrient availability, and biological activity, is usually made considering soil as being uniform in the reference layers and its characteristics varying in space according to gradients. The potential fertility is thus estimated for homogeneous soil volumes. However, soil layers and horizons are mainly not homogeneous and discontinuous. The soil rooting capacity, in particular, can be limited by the presence of obstacles, such as bedrock, cemented layers and stones, but also by soil masses which are so dense that cannot be penetrated by roots. These compact masses are almost always overlooked and not considered in the estimation of soil fertility. In this work, an innovative method, which considers the presence of clods in the soil volume, is proposed for estimating the potential soil rooting capacity. Clods are the soil masses or aggregates which are too compact to be explored by roots. Correcting the values of available nutrients and water holding capacity according to the potential soil rooting capacity increases its correlation with plant phenology and the agronomic result. The method could be particularly useful when planning the operations to be carried out before the planting of specialized tree crops.