Effect of Nitrogen Fertilization on Growth and Yield of Industrial Hemp (Cannabis sativa L.)

Fibre hemp is grown for a multitude of end products derived from its cannabinoids, seed, fibre and wooden core. A key factor that influences the quantity and quality of the production of hemp is nitrogen fertilization. The aim of this study was to determine the response of five well-adapted industrial hemp cultivars to different nitrogen fertilization rates during the 2016 growing season. The experiment was laid out in a split-plot design with two replicates, five main plots (hemp cultivars: ‘Bialobrzeskie’, ‘Tygra’, ‘Felina 32’, ‘Sanhtica 27’, ‘Futura 75’) and sub-plots [fertilization treatments: control (N0), fertilizer 46-0-0 at 120 kg ha-1 (N1), 180 kg ha-1 (N2), 240 kg ha-1 (N3)]. For the computation of height, biomass yield, stem dry weight, length and weight of the inflorescences and mean seed weight, 10 plants were randomly selected in each plot. In general, increasing N fertilization rate positively impacts hemp biomass yield, stem dry weight, plant height, and inflorescence indices. Biomass yield, stem dry weight and inflorescence weight increased by 37.3%, 48.2% and 16%, respectively, with the application of 240 kg N ha-1 when compared with the unfertilized control. Plant height and inflorescence length increased from 1.66 to 1.76 m and from 66.2 to 82.9 cm, respectively, with the application of the higher N rate compared with the control, while there were no significant differences between the fertilization treatments for mean seed weight. The varieties ‘Tygra’ and ‘Futura 75’ showed the highest values for all the measurement characters. Our results indicate that hemp responded well to the addition of N fertilizer

Aromatic plant Melissa officinalis extracts selectivity in various biomass crop and legume species

Saabunud / Received 17.06.2020 ; Aktsepteeritud / Accepted 10.07.2020 ; Avaldatud veebis / Published online 10.07.2020 ; Vastutav autor / Corresponding author: Panagiotis Kanatas e-mail: [email protected] effects of various plants can be exploited for use against weeds; however, the selectivity in different crops is also important. In the current study, the effects of lemon balm (Melissa officinalis) allelochemicals on seed germination and seedling emergence of three biomass crops and three legume species were evaluated. Seed germination of rapeseed was reduced by 19, 30, 56, and 80% in the concentrations of 1, 2, 5 and 10%, respectively, as compared to the control group, whereas sweet sorghum seeds showed a more intermediate response and sunflower germination was affected only by the highest concentration. Seed germination of common bean was by 25, 34 and 60% lower at 1, 2 and 5% extract concentrations, respectively, in comparison to the control whereas up to 85% reduction of seed germination was recorded in 10% concentration. Peanut seed germination percentage ranged between 72 and 47% of control in 5 and 10% concentrations, respectively, while soybean germination was least affected from M. officinalis leaf extracts since it was reduced by only 25 and 41% in 5 and 10% concentrations, respectively, as compared to the control. Seedling emergence of rapeseed was reduced by 14, 25, 46, and 79% in the concentrations of 1, 2, 5 and 10%, respectively, as compared to the control whereas lemon balm extracts showed increased selectivity on the sunflower. Soybean emergence was reduced by only 27 and 46% in 5 and 10% concentrations, respectively, in comparison to the control whereas common bean’s seedling emergence was reduced up to 35% even in 2% concentration. Allelopathic response index values confirmed that sunflower and rapeseed were the least and most sensitive biomass crops to lemon balm allelochemicals, respectively, whereas sweet sorghum showed an intermediate response. Increased was the selectivity of the aqueous leaf extracts on soybean, whereas seed germination and seedling emergence of peanut were more affected and common bean was the most sensitive crop. Further research is needed to investigate the selectivity of M. officinalis and other aromatic plants’ allelochemicals on various crops and under different soil and climatic conditions to optimize their efficacy as tools of more eco-friendly weed management strategies

Seed priming effects on germination and first growth of the medicinal plant Achillea millefolium L.

This study evaluated the effects of seed priming on germination and growth of A. millefolium by means of laboratory and greenhouse experiments conducted during 2018 in the Agricultural University of Athens. Treatments were GA3 (400 and 800 ppm), potassium nitrate (2% and 4%), polyethylene-glycol (soaking for 12 and 24h) besides an untreated control. Experiment in Petri dishes revealed that GA3 at 400 ppm, potassium nitrate (at concentration 2 and 4%) and PEG significantly increased germination percentage of A. millefolium, while germination rate was also significantly improved as a result of all seed priming techniques. In addition, due to the soil experiment, seedling emergence was significantly increased by GA3 at 400 ppm, potassium nitrate (at both concentrations) and PEG compared with the untreated seeds. Dry biomass of the young seedlings was significantly enhanced by means of GA3 (at 400 and 800 ppm), KNO3 (4%) and PEG for 24 h, indicating the potential effect of seed priming on first growth as well. The results of the present study revealed the significant positive effects of seed priming on A. millefolium seed germination, seedling emergence and early growth

The Role of Mulching with Residues of two Medicinal Plants on Weed Diversity in Maize

In the present study, there were studied the effects of mulch with the residues of two aromatic and medicinal plants (Sideritis scardica Griseb and Echinacea purpurea) on weed flora and first growth of a maize crop. A field and a pot experiment were conducted at Agricultural University of Athens. In particular, the field experiment was conducted under organic conditions, while in the pot experiment special attention was paid to the first growth of maize plants under the effect of plant residues. Our results showed that there was a significant effect of plant residues on weed flora. The incorporation of Sideritis sp. residues resulted to a lower number of different weed species (low richness) and an intense effect on most weed species. During the early growth stages of maize there was a satisfactory control of the broadleaf weeds after the incorporation of S. scardica, resulting to a significantly lower biomass. However, this effect progressively disappeared, with E. purpurea mulch progressively showing a higher phytotoxic activity. The pot experiment revealed that there was not any negative effect of mulching on maize seed germination, emergence and early growth

Organic Agriculture and Innovative Crops under Mediterranean Conditions

Climate change is the greatest environmental threat facing humanity worldwide. Areas of South-East Europe and Mediterranean basin are expected to be among the most vulnerable countries to climate change. As a result of climate change, new species and crops have been introduced and may be introduced in the coming years. In addition, FAO considers that Organic Agriculture is an effective mitigation strategy to climate change and can build robust soils that adapt better to weather extremes associated with climate change. This review provides an overview of the growth performance of new innovative crops, including chia, camelina, quinoa, teff and nigella and retrovative crops such as flax and emmer wheat, based on experimental investigations conducted under Mediterranean conditions and organic cropping system. Several studies, performed under organic system, have proved that innovative crops can also be grown for alternative uses. Quinoa and chia could be successfully used in animal feed. Moreover, quinoa could be exploited as a medicinal plant due to saponins extracted from seed coats. Nigella and camelina seeds contain oils which can have several uses in pharmaceutical and food industries. Flax seed oil is rich in omega-3 fatty acids and can be accepted in the diets designed for specific health benefits. According to the literature, it is observed that innovative crops cultivated under organic system present better quality and similar yields as with those cultivated under conventional system, and in some cases, even higher. Taking all these into account, organic agriculture could also be characterized as innovative and not only as traditional

Effect of N and P Fertilization on Weed Flora of Maize (Zea Mays L.) Crop

From May to September 2016, a corn hybrid was sown in a field in central Greece. The experiment was laid out in a randomized complete block design with six replications and five fertilization treatments, namely NutriSphere-N Nitrogen Fertilizer (75%), NutriSphere-N Nitrogen Fertilizer (100%), AVAIL Phosphorus Fertilizer (75%), AVAIL Phosphorus Fertilizer (100%) and unfertilized (control). Data analysis confirmed that the different type of fertilization has a significant effect on the composition of weed flora. In particular, the results of the present study indicated significant differences between the fertilization treatments concerning density and diversity of weeds. Furthermore, weed diversity in the control treatment was highest, while it was lower in plots receiving application of N and P. However, total weed dry mass was lower in plots receiving no fertilizer and P fertilization, and highest in plots receiving N. Differences in terms of weed growth between the two types of fertilization could be attributed to differences revealed in the composition of the weed flora.

Effects of Tomato Pomace Composts on Yield and Quality of Processing Tomato (Lycopersicon esculentum Mill.)

Organic farming encourages the use of organic waste materials as substitutes for chemical fertilizers. Tomato pomace presents an alternative to inorganic fertilizer. A field experiment was carried out to evaluate the influence of tomato pomace composts and nitrogen fertilization on agronomic and quality parameters of the processing tomato. The experiment was laid out in a randomized complete block design with three replications and five fertilization treatments (untreated, nitrogen fertilizer, tomato pomace with biocyclic humus soil, tomato pomace with manure and tomato pomace with plant residues). The results showed that the highest average fruit weight and fruit yield (163.4 t/ha) were found in plots subjected to nitrogen fertilization, while the highest total soluble solids content (4.29 °Brix), and L* and a* colour parameters, important quality parameters to processing tomato industry, were obtained through the application of tomato pomace mixed with biocyclic humus soil making organic tomatoes suitable for processing tomato industry

Effects of Cropping System (Organic and Conventional) on the Fiber Quality Index, Spinning Consistency Index and Multiplicative Analytic Hierarchy Process of Cotton (Gossypium hirsutum L.)

Markets for organically produced high quality cotton (Gossypium hirsutum L.) are projected to increase. Field experiments were conducted in Palamas, Karditsa in Central Greece, to compare the effects of two cropping systems on fiber quality of three cotton cultivars. The experiments, conducted during three years, were laid out in a split plot design with four replicates, two main plots (organic and conventional system) and three sub-plots (cotton cultivars). Findings suggest that fiber quality index (FQI), spinning consistency index (SCI) and multiplicative analytic hierarchy process (MAHP) are three indices that could be integrated in a useful protocol for the evaluation of different cropping systems for cotton cultivation. In particular, our results indicate that in general there was not any superiority of conventional compared to the organic cropping system regarding fiber quality as shown by the above mentioned indices. Regarding the length of the cotton fiber, this was positively correlated with micronair and the uniformity index of the cotton fiber. The organic system resulted to higher values of SCI than the ones of the conventional (1547.9 and 1522.3, respectively). The present 3-years study shows that organic cultivation of cotton can ensure high fiber quality and this was clearly confirmed by means of the several important indices