Yield and olive oil characteristics of a low-density orchard (cv. Cordovil) subjected to different irrigation regimes

The impact of different irrigation scheduling regimes on the quantity and quality of olive oil from a low-density olive grove in southern Portugal was assessed during the irrigation seasons of 2006 and 2007. Olive trees were subjected to one of the following treatments: A—full irrigation; B—sustained deficit irrigation (SDI) with 60% of ETc water applied with irrigation; C—regulated deficit irrigation (RDI) with irrigation water applied at three critical phases: before flowering, at the beginning of pit hardening and before crop harvesting and D—rain-fed treatment. Olive oil yield was significantly higher than rain-fed conditions in 2006, an “on year” of significant rainfall during summer. No significant yield differences were observed in the following “off year”. Among the irrigated treatments, olive oil production of treatment B was 32.5% and 40.1% higher in 2006 and 2007, respectively than the fully irrigated treatment A, despite receiving 49% less irrigation water. Such strategy could allow for an efficient use of water in the region, of very limited available resources, and for modest but important oil yield increase. Nonetheless, on the “on year” of 2006 treatment C used 13.9% of the water applied to treatment B and produced only 23.9% less olive fruits which could also make it illegible as the next possible strategy to use for irrigating olive trees in the region, provided that water is secured latter in the summer, a period of vital importance for oil accumulation and very sensitive to water stress as the poor results of 2007 revealed. The different treatment water regimes did not impact on the chemical characteristics of olive oils that were within the set threshold limits. Similarly, the sensory characteristics of the olive oils as well as bitterness and pungency were negligible for all treatments allowing them to be assessed as of “superior quality”.Overall, irrigation treatments had no influence on the commercial value of produced oils, being all classified as “extra virgin”. Such funding may be of vital importance to farmers willing to further their irrigation area, save water and still retain the protected designation of origin (PDO) seal of quality for their oil.     

Changes in broccoli (Brassica oleracea L. Var. italica) health-promoting compounds with inflorescence development

Changes in phenolic compounds, total glucosinolates, and vitamin C were monitored during the productive period along five inflorescence development stages of three broccoli commercial cultivars (Marathon, Monterrey, and Vencedor). In an attempt to identify differences due to agronomic factors, broccoli cultivars were grown under different sulfur fertilization with poor (15 kg/ha) and rich (150 kg/ha) rates. Phenolic compounds and vitamin C concentrations showed, in all broccoli cultivars, a rising trend from the first stage until the over-maturity stage, both for rich and poor sulfur fertilization. Significant differences were detected in the first two stages between rich and poor sulfur fertilization in total glucosinolates for all broccoli cultivars, where the highest concentration was always observed in the second development stage (used as minimally processed product) during poor fertilization. With regard to the last three stages, the glucosinolate concentration in the poor sulfur fertilization started to slope down until the over-maturity stage. Where rich sulfur fertilization is concerned, the highest level was reached during the third stage (used as minimally processed product also), and after that, glucosinolate concentration decreased until the fifth stage.     

Effect of high-intensity pulsed electric fields processing and conventional heat treatment on orange-carrot juice carotenoids

Liquid chromatography (LC) was the method of choice for quantification of carotenoids (including geometrical isomers) to evaluate the effects of high-intensity pulsed electric field (HIPEF), a nonthermal preservation method, with different parameters (electric field intensities and treatment times), on an orange-carrot juice mixture (80:20, v/v). In parallel, a conventional heat treatment (98 degrees C, 21 s) was applied to the juice. HIPEF processing generally caused a significant increase in the concentrations of the carotenoids identified as treatment time increased. HIPEF treatment at 25 and 30 kV/cm provided a vitamin A concentration higher than that found in the pasteurized juice.     

Peroxicoagulation and Solar Peroxicoagulation for Landfill Leachate Treatment Using a Cu–Fe System

Leachates, particularly those from mature landfills, are difficult to treat by biological processes because of their high toxicity and low biodegradability. Therefore, the development of new treatment technology is necessary. The treatment of landfill leachate by peroxicoagulation and solar peroxicoagulation using a batch electrolytic reactor with a Fe cathode and a Cu anode is proposed. The tested operational variables included pH (2.8 and 8.2), current density (11 and 16 mA cm^?2), treatment time (5, 10, 15, 20, 25, and 30 min), and presence of solar ultraviolet (UV) light and were collected using a compound parabolic collector. The optimum conditions were a pH, current density, and treatment time of 2.8, 16 mA cm^?2, and 10 min, respectively. The presence of UV did not have a significant effect. The chemical oxygen demand and biochemical oxygen demand removed were 62.3% and 55.5%, respectively. The results of UV-visible absorption, fluorescence, and Fourier transform infrared spectroscopy measurements confirm the oxidation process.     

Nitrate uptake by Vicia faba L. Plants: A physiological approach 1

This study was conducted to obtain information on the properties of the nitrate (NO₃ ^‐) uptake system in Vicia faba. The results showed that in plants grown in the absence of NO₃ ^‐, they cannot absorb it upon initial exposure to this anion. When this plant makes contact with environmental NO₃ ^‐, NO₃ ^‐uptake by the roots is progressively induced. However, in NO₃ ^‐‐grown plants, the uptake system is yet induced so they had the ability to take up NO₃ ^‐ at high rates from the beginning. The Michaelis’ constant (K,_M) and maximum uptake rate (V_max) were estimated from measurements of NO₃ ^‐ depletion in the uptake medium. The apparent K_M value for net NO₃ ^‐ uptake in induced V. faba plants was 60 μM and the corresponding V_max 0.44 umol NO₃ ^‐ (g FW)^‐1 h^‐1. This last value was low compared with that of other species, while K_M is in the range for other higher plants. From the results of our experiments at low and high NO₃ ^‐ concentrations, we discuss the possibility of the existence of two NO₃ ^‐ uptake systems, one of a high affinity (functioning at low NO₃ ^‐concentrations) and another of low affinity (operative at high NO₃ ^‐ level in the medium).     

HPLC-DAD-ESI-MS/MS characterization of pyranoanthocyanins pigments formed in model wine

Formation of wine pyranoanthocyanins in model wine was monitored by HPLC-DAD-ESI-MS/MS, using red grape skin extracts and wine fermentation metabolites (acetaldehyde, pyruvic and acetoacetic acids, and diacetyl) and also hydroxycinnamic acids (p-coumaric, caffeic, ferulic, and sinapic acids). Pyruvic acid and acetaldehyde reacted fast, the first reaching high product yield and the second inducing mainly pigment polymerization. In contrast, acetoacetic acid and diacetyl reacted slowly with poor product yields. Hydroxycinnamic acids progressively reacted without apparent formation of polymeric pigments, the reaction rate and yield increasing as the number of hydroxy/methoxy groups did. Substituent at C-10 strongly affected the visible maximum absorbance wavelength, whereas B-ring substitution pattern or sugar acylation exerted little effect. The 10-methylpyranoanthocyanins formed from acetoacetic acid were also found as side products in the formation of 10-carboxypyranoanthocyanins. Finally, we report for the first time on UV-vis and MS spectral data of 10-acetylpyranoanthocyanins formed from diacetyl, and their occurrence in commercial red wines is suggested.     

Quality and maximum profit of industrial tomato as affected by distribution uniformity of drip irrigation system

The tomato industry reformed its system of payment by weight of tomato, introducing a corrective system based on percent level of fruit dry matter produced. Such a decision implies significant changes in the management of irrigation systems, with a need to emphasize the technological quality of the marketable product. Three levels of distribution uniformity of the irrigation system are analysed, and related production functions of crop yield and percent of dry matter are presented as well as their use on the optimisation of dry matter, expected revenues and seasonal applied water. Results are critically influenced by the distribution uniformity. They demonstrate the inter-relationship between crop production, percent fruit dry matter and irrigation management, and the importance of considering non-uniformity in the economic analysis of industrial tomato production. Decreases in uniformity lead to a reduction in dry matter production per unit land. Decreases in dry matter are also observed with increasing levels of seasonally applied water, with the optimal level always lower than the required for maximum yield. Such interaction suggests a continuous and inverse relationship between profit and water applied. However, due to the corrective system of payment, by levels of percent of dry matter produced, for some uniformity, the expected revenue follows the yield-water production function instead of the dry matter function. This fact introduces disturbances in the optimal water applied inducing higher than expected levels of water applied for profit maximisation. The simulated data also show that incentives to switch to new systems or management practices able to raise the distribution uniformity result more from profit losses than increases in water price.     

Using midday stem water potential for scheduling deficit irrigation in mid–late maturing peach trees under Mediterranean conditions

Irrigation techniques that reduce water applications are increasingly applied in areas with scarce water resources. In this study, the effect of two regulated deficit irrigation (RDI) strategies on peach [Prunus persica (L.) Batsch cv. “Catherine”] performance was studied over three growing seasons. The experimental site was located in Murcia (SE Spain), a Mediterranean region. Two RDI strategies (restricting water applications at stage II of fruit development and postharvest) based on stem water potential (Ψ_s) thresholds (?1.5 and ?1.8 MPa during fruit growth and ?1.5 and ?2.0 MPa during postharvest) were compared to a fully irrigated control. Soil water content (θ_v), Ψ_s, gas exchange parameters, vegetative growth, crop load, yield and fruit quality were determined. RDI treatments showed significantly lower values of θ_v and Ψ_s than control trees when irrigation water was restricted, causing reductions in stomatal conductance and photosynthesis rates. Vegetative growth was reduced by RDI, as lower shoot lengths and pruning weights were observed under those treatments when compared to control. However, fruit size and yield were unaffected, and fruit quality was slightly improved by RDI. Water savings from 43 to 65 % were achieved depending on the year and the RDI strategy, and no negative carryover effect was detected during the study period. In conclusion, RDI strategies using Ψ_s thresholds for scheduling irrigation in mid–late maturing peach trees under Mediterranean conditions are viable options to save water without compromising yield and even improving fruit quality.     

Tree density and site quality influence on Pinus halepensis Mill. reproductive characteristics after large fires

In Spain, many Pinus halepensis Mill. forests have been seriously affected by significant forest fires in the past decade, in 1994 alone, more than 100 000 ha were burned in Eastern Spain. In order to study the reproductive characteristics of P. halepensis after forest fires, six locations were selected in four areas affected by serious fires in the summer of 1994, and the following different precipitation zones were studied: dry-subhumid, dry and semi-arid. Ten years after the fires, data relevant to the production of pine cones: serotinous (grey), mature (brown), immature (green) and opened cones, was collected from areas with natural post-fire regeneration. Various cone and seed characteristics, such as pine cone seed number and weight, and germination percentage, were measured. The results showed greater production of cones and strobili in high-density sites. The biggest cone sizes (volume) and seed number per cone were related to site quality (dry-subhumid precipitation zone). Also, viability and germination percentages were higher with better site quality, with significant differences in values for serotinous and non-serotinous cones. Despite these differences, the canopy seed bank was large enough to ensure regeneration in this area for this age stand.     

Deep planting with shelters improves performance of different stocktype sizes under arid Mediterranean conditions

New Forests - Increasing plant size has been considered a way to improve survival and growth of planted containerized stock under dry conditions. Additionally, deep planting provides advantages to...