Background Sweet pepper is considered one of the most important vegetable crops cultivated for local consumption and exportation. Under greenhouse conditions, the effects of different rates of yeast and compost tea on vegetative growth, leaves mineral content, fruit yield and quality were studied for two consecutive years 2018/2019 and 2019/2020 under soilless conditions. Nine treatments of compost tea (CT) and or dry yeast (DY) were applied using control (sprayed with distilled water); CT (10L/fed.); CT (20 L/fed.); DY (3 g/L); DY (6 g/L); CT (10L/fed.) + DY (3 g/L); CT (20L/fed.) + DY (3 g/L); CT (10L/fed.) + DY (6 g/L) and CT (20L/fed.) + DY (6 g/L). Results Results showed that the mixture of compost tea and dry yeast at a rate of 20 L./fed. plus 6 g/L, respectively, had significantly increased vegetative growth, fruit physical quality (length, diameter and fresh weight), total yield, leaves mineral content (N, P and K) and fruit nutritional value content (calcium and vitamin C). The maximum return or profit comes from the CT (20 L/fed) + DY (6 g/L) followed by CT (20 L/fed) + DY (3 g/L.) Conclusion It is clear that all treatments enhanced the yield and the fruit physical parameters of the studied plants as well as all treatments are economically feasible including the control treatment. However, looking at the Revenue/Cost ratio (R/C), one can find that the maximum net revenue comes from the mixture of CT (20 L/fed) plus DY (6 g/L) with a net revenue about 192.72 L.E./m2 and R/C ratio of 1.90, followed by CT (20 L/fed) + DY (3 g/L.).

Thyme (Thymus vulgaris L.) belongs to the lamiaceae family. It is characterized by its medicinal and economic values. Thymus is grown worldwide for cosmetic and medical use. Plant bio-stimulants are classified as substances which have positive effects on growth and productivity of plants. Bio-stimulants are obtained naturally from various economically and environmentally viable sources. The current experiment aimed to investigate the response of thymus physical and chemical properties to the different types and concentrations of bio-stimulators under soil less culture conditions for two successive seasons 2019 and 2020. Thymus seedlings were planted in pots filled with mixed media of perlite: sand (1:1v/v). Plants were sprayed with aqueous solution of ascorbic acid (1 and 2g/l), aspartic acids (500 and 1000 ppm) and dry yest (2 and 4g/l) and combination of them compared with control. The herp was harvested in mid- July (First cutting) and first week of October (second cut). Growth and yield characters were measured. The essential oil percentage was determined and analyzed by GC in both cuts from the fresh herb. Results showed that, spraying of mixtures of ascorbic acid (2g/l), aspartic acids (1000 ppm) and yeast (4g/l)) significantly increased yield, total carbohydrates, total phenols, total pigments, essential oil percentage and yield as well as its NPK content characters and components of essential oil high contents of thymol, ? and ? –Pinene during both cuts and for both seasons. Economic evaluation was carried out by calculating with the highest return in the mixture treatment. It is clear that all treatments are economically feasible however, one can find that the maximum return or profit comes from mixture treatments where the benefit to cost ratio were 3.99 and 3.9 for Mix2 and Mix1 respectively.

Lavender (Lavandula officinalis L) has high economic and medicinal value. The current experiment was carried out during the two successive seasons 2018/2019 and 2019/2020. It aimed to investigate the effect of compost, biofertilizers (Azospirillum spp., Azotobacter spp.), mixtures of them, and active dry yeast on vegetative and chemical composition of lavender herbs cultivated on plastic pots filled with sandy soil. Fertilizers were added to the plant roots three times during the growing seasons. Growth and yield characteristics were quantitatively assessed and were compared to each other. Lavender essential oil percentage was determined from the fresh herb, as well as the oil constituents to assess the oil quality. Moreover, the study was tailed by an economic assay to determine the study feasibility. Results indicated that application of biofertilizers significantly increased plant height, number of branches, fresh weight, dry weight, yield, % essential oils, N, P, K%, crude protein content, total pigment, antioxidant, flavonoid, phenol, total carbohydrates, and free amino acids contents compared with the control treatment. Mixtures of bacteria (Azotobacter, Azospirillum) treatments were the superior in all measured variables. It also increased the percentage of essential oils. The main essential oils (EO) constituents were linalool, linalyl acetate, borneol, terpinen4-ol, and 1,8-cineole. From the economic point of view, also the biofertilizer treatments were feasible, this could result in environmentally safe plants to minimize the hazards of pollution caused by using mineral fertilizers. The economic evaluation indicated that mixtures of bacteria resulted in the highest value of net return for lavender plants.

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Lavendula officinalis plants were grown in perlite substrate culture, treated with three nicotinamide concentrations (0, 75 and 100 mg/L), also foliar spray with two different irrigation scheduling (10, 15 times/day) were used. Essential oil (extracted from two cuts) composition was identified using gas chromatography (GC). Essential oil samples were tested for their antimicrobial activity against five Gram positive bacteria, five Gram negative bacteria, six fungi, and four yeasts. The antimicrobial potency was determined by measuring the inhibition zone (mm) using whole plat diffusion technique. GC data showed the superiority of 1,8 cineol which varied from one cut to another according to the rate of irrigation and application of nicotinamide. Linalool was the second major constituent in all treatments; it showed vacillation due to nicotinamide application and the rate of irrigation from one cut to another. Antimicrobial inhibitory effect of most of the resultant lavender essential oils increased with increasing their volume from 2 to 5 µl. Most strains of fungi and Gram positive and negative bacteria showed high sensitivity and were inhibited to a great extent. Different strains of yeast showed high resistance and survived essential oils test. Data clearly indicated the marked inhibitory effect of lavender crude oil samples against several human and plant pathogens and non pathogenic micro organisms.