Growth Analysis of Quinoa (Chenopodium quinoa Willd.) in Response to Fertilization and Soil Tillage

Growth analysis is an appropriate method for plant response to various environmental and cultural conditions during plant life. A 2-year experiment was conducted to evaluate the effect of soil tillage and fertilization on the growth and growth parameters of quinoa crop and to determine the association between yield and growth characteristics at both the single plant and crop stand level. The experiment was laid out in a split-plot design with two replicates, two main plots [conventional (CT) and minimum tillage (MT)] and four sub-plots [fertilization treatments: untreated, inorganic fertilization of 100 (N1) and 200 kg N ha-1 (N2) and sheep manure]. The highest absolute growth rate (AGR) and crop growth rate (CGR) values were recorded between the middle of vegetative growth stage and the beginning of anthesis (50-75 DAS) under conventional tillage coupled with manure (AGR: 0.4577 g day-1, CGR: 11.44 g m-2 day-1) and with N2 treatment (AGR: 0.4521 g day-1, CGR: 11.31 g m-2 day-1). Concerning specific leaf area (SLA), the highest value (150.58 cm2 g-1) was found at 75 DAS in N2 treatment. Leaf area index (LAI) were positively affected by soil tillage and fertilization with greatest values found under conventional tillage coupled with N2 treatment (5.110 m2 m-2). The highest seed yield was observed in N2 treatment (2488 and 2388 kg ha-1 under CT and MT, respectively). As a conclusion, the cultivation under conventional tillage and the increasing levels of applied nitrogen up to 200 kg N ha-1 increases crop growth and yield

ORGANOPHOSPHORUS PESTICIDE RESIDUES IN GREEK VIRGIN OLIVE OIL: LEVELS, DIETARY INTAKE AND RISK ASSESSMENT

International audienceIn this study, the occurrence of organophosphorus pesticides (OPs) and metabolite residues was investigated in 167 samples of Greek virgin olive oil during a two-year (2004–2005) sampling campaign. A total of 30.5% of samples contained detectable residues while only one sample contained dimethoate residues higher than the maximum residue limits. Among the seven detected OPs, fenthion and fenthion sulfoxide residues were detected in 10.8% and 14.4% of the samples respectively at 0.003 to 0.61 mg kg-1 followed by dimethoate that was detected in 10.2% of the samples, at 0.003 to 0.057 mg kg-1. The acute dietary risk assessment was evaluated by determining the National Estimated Short-Term Intake (NESTI) while for the chronic dietary risk assessment the National Theoretical Maximum Daily Intake (NTMDI) and National Estimated Daily Intake (NEDI) were calculated. The estimated intakes (NESTI and NEDI) of each pesticide were <7% and <0.86%, much lower than the corresponding acute reference doses (ARfDs) and acceptable daily intakes (ADIs), respectively. Furthermore, a cumulative risk assessment was performed using the Hazard Index (HI) and the Toxicity Equivalence Factor (TEF) approaches taking into account that OPs share the same toxicological mechanism. The determined HI and TEFs were found to represent only a small portion of the respective ADIs or ARfDs. These results indicate that neither acute nor chronic risk derives for the Greek population through olive oil consumption

Spatiotemporal Variation and Risk Assessment of Pesticides in Water of the Lower Catchment Basin of Acheloos River, Western Greece

A three-year monitoring survey (March 2005–February 2008) was conducted to investigate, on monthly basis, the presence of thirty pesticides belonging to various categories and metabolites, in Acheloos River (Western Greece), one of the most important water resources in Greece. Six sampling stations along the river were established. Water analyses were performed using solid-phase extraction combined with gas chromatography with flame thermionic detector and mass spectrometry. Statistical analysis using one-way ANOVA and Duncan’s multiple range test (P<0.05) was used to compare annual mean concentrations of pesticides, seasonal and spatial distribution. In general, the highest mean concentrations of the pesticides were recorded at the three stations downstream. The greatest average concentrations were determined during spring and summer in agreement with the pesticide application period. The observed lower concentrations after 2006 reflect the land-use change because of the elimination of tobacco, the main cultivation of the area for many decades. The compounds most frequently detected were diazinon (78.6%), DEA (69.3%), and fenthion (52.6%). Environmental risk assessment using risk quotient (RQ) approach showed high risk for six insecticides in 2005 and one in 2007. A compliance with the European Environmental Quality Standards (EQS) was observed for the priority pesticides

Determination of Antioxidant Charge and Total Phenolic Content in Greek aromatic plants by EPR/UV-Vis Spectroscopy

Aromatic plants and herbs are among the more important sources of phenolic compounds, which have been reported to show strong antioxidant activity. In the present work the total phenolic content and the antioxidant charge of five aromatic plants, Origanum vulgare L., Rosmarinus officinalis L., Ocimum basilicum L., Salvia officinalis L. and Achillea millefolium L., biologically grown in Western Greece, was determined by UV-vis and Electron Paramagnetic Resonance (EPR) spectroscopy. Dried plant leaves extracted in 50% methanol/ 48,5% H2O/ 1,5% formic acid solution were measured by UV-vis spectroscopy for the determination of total phenolics. Quantitative analysis has been done by using Gallic acid as standard solution. In addition the dry matter of plant leaves was measured at 77Kelvin by EPR spectroscopy. The EPR spectra of all samples contained stable radical signal with g-values 2.0046-49 and a linewidth of 3-5Gauss. These are characteristic of phenolic or quinone-type radicals with the unpaired electron partially on the Oxygen atom of the phenolic ring. Quantitative analysis of the radicals has been done using DPPH [1mm3 2x1013 spins] as reference. The calculations have been done per dry mass of the material. The present results reveal significant differences of radical concentration between samples of different origin by EPR spectra. The higher radical content was measured in Origanum vulgare L. and the lower in Ocimum basilicum L. plant leaves respectively. In addition a significant difference in total phenolics content was determined between plants. The higher concentration was found in Origanum vulgare L. and the lower in Achillea millefolium L. plant leaves respectively. It is concluded that a fraction of the total phenolics accumulation corresponds to the redox active antioxidant charge in plant leaves

Seed and Saponin Production of Organic Quinoa (Chenopodium quinoa Willd.) for different Tillage and Fertilization

Field experiment was conducted to determine the effects of tillage systems and fertilization on growth, yield and quality of quinoa crop (Chenopodium quinoa Willd.). The experiment was laid out in a split-plot design with four replicates, two main plots [conventional tillage (CT) and minimum tillage (MT)] and three sub-plots (fertilization treatments: control, cow manure and compost). The soil porosity (45.5-49.75%) and total nitrogen (0.144-0.173%) were higher in soils subjected to MT system than under CT. In soil porosity, an interaction between fertilization and tillage system was found. The highest leaf area index (4.47-5.03), dry weight (8650-9290 kg ha-1) and root density (1.03-1.21 cm cm-3) were also found in MT. Moreover, there were significant differences between the organic fertilization treatments concerning the LAI, dry weight and root density. The highest seed yield (2485-2643 kg ha-1) and saponin content (0.42-0.45%) were found in cow manure and compost treatments. Also, the highest saponin yield (7.70-12.05 kg ha-1) was found in the MT system. Saponin yield had positive and significant correlation with total N (r=0.866). In quinoa measurements, an interaction between fertilization and tillage system was not found. The present results indicated that MT and organic fertilization increase saponin yield of quinoa

Root growth dynamics and productivity of quinoa (Chenopodium quinoa Willd.) in response to fertilization and soil tillage

Quinoa is a gluten-free pseudocereal crop recognized for its exceptional nutritional properties. A 3-year field experiment was conducted to evaluate the influence of soil tillage and fertilization on root growth and productivity of quinoa. The experiment was laid out in a split-plot design with two replicates, two main plots [conventional (CT) and minimum tillage (MT)] and four sub-plots [fertilization treatments: untreated, inorganic fertilization with 100 (N1) and 200 kg N ha−1 (N2), and sheep manure]. Mean weight diameter (MWD) of soil aggregates, total porosity, organic matter and soil total nitrogen increased with the long-term fertilization with sheep manure. The major part of the roots (approximately 70%) is concentrated in the 0-30 cm soil layer. Root length density increased with increased rate of applied nitrogen, and a higher value (1.172 cm cm−3) was found in N2 plots. Additionally, higher root mass density (1.114 mg cm−3) was observed under MT. Plant height and dry weight were clearly affected by fertilization, with higher values obtained in N2 plots. Moreover, it was observed that quinoa cultivated under CT and N2 treatment produced a higher seed yield (2595 kg ha−1). As a conclusion, increasing the levels of applied nitrogen up to 200 kg N ha−1 improves root growth and consequently the yields of quinoa