mohammad hossein lebaschi

The present study was carried out to evaluate yield and precipitation efficiency index of Bakhtiari savory (Satureja bachtiarica Bunge.) influenced by organic fertilizers and different plant densities under dry land farming conditions. The experiment was conducted as a split plot based on a randomized complete block design with three replications at Homand rangeland research station of Damavand, in 2018 and 2019. The main factor was organic fertilizer in three levels, including cattle manure (30 t. ha-1), enriched wheat straw (10 t. ha-1), and control. The sub plots included three levels of plant densities (26666, 40000, and 80000 plant ha-1). The amount of effective rainfall in the first and second years was 278 and 390 mm, respectively. The results showed that the interaction of year and organic fertilizer as well as year and plant density led to a significant increase in dry weight yield and precipitation efficiency index. The maximum dry weight yield was 385 kg. ha-1 in the second year and cattle manure treatment. The highest precipitation efficiency index with 0.986 kg.mm-1. ha-1 was observed in the second year and cattle manure treatment. In this research dry matter yield and precipitation efficiency increased by using cattle manure and high plant density in the second year. In general, adaptive capacity and adequate yield of Bakhtiari savory showed the high precipitation efficiency index of this species, which can be used as a suitable species for dryland agriculture. These results can be remarkably beneficial to change the cultivation pattern in low-efficiency dryland farming.

Antioxidant enzymes synthesis in plant is an essential process for increasing the plant's tolerance to abiotic stress. Plant cells and their organs are protected by antioxidant enzymes with removing reactive oxygen species (ROS). To investigate the effect of plant density and organic fertilizers on the antioxidant enzymes activity including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), ascorbate peroxidase (APX) and electrolyte leakage (EL) of Bakhtiari savory (Satureja bachtiarica Bunge.), a field experiment was carried out at dryland farming conditions in Research station of Forests and Rangelands of Homand, Damavand, during 2018 and 2019. The results indicated that organic substrates and plant density significantly changed antioxidant enzyme activities (P≤0.05). Under these conditions, cattle manure reduced the antioxidant enzymes of APX, SOD, PPO, and EL. High plant density resulted in less SOD, POD, APX, CAT, and EL compared to low plant density. Compared to control (non- organic fertilizer), cattle manure decreased the activity of SOD, CAT, PPO and EL by 8, 14, 8, and 28%, respectively, in second year-plants. High plant density decreased the activity of SOD, POD, APX, and CAT by 12, 25, 14, and 23%, respectively. The present study can suggest the use of cattle manure and high plant density to reach the optimal growth under dryland farming conditions through controlling antioxidant enzymes production.

The use of environmental friendly fertilizers is the main agricultural practice to improve the plant quality and quantity. The present study aims to assess the effect of organic and inorganic fertilizers on flower and stigma yield, biochemical properties and essential oil (EO) composition of saffron (Crocus Sativus L.) in research station of Hamand Absard, Iran. The plants were treated with cattle manure (20 t ha-1) and foliar application of delfard (7 kg ha-1) and floral P (2.5 kg ha-1) in a completely randomized block design (CRBD) with three replications under dryland farming system. The results showed significant increases of flower number and yield under all fertilizers compared to control. The yield of fresh and dry stigma under manure application was higher than floral and delfard. The response of chlorophyll (Chl) concentration was different under fertilizers. Floral and manure application led to higher Chl a compared to control. Chl b under manure and delfard was significantly higher than control and floral. TPC and TFC were significantly improved by organic and inorganic fertilizers. The main improvement of TPC and TFC was obtained under manure application followed by floral and delfard. GC/MS analysis showed the main EO composition were Methyl pentanoate (25.8- 62.15%) followed by Dihydro- β- ionol (17.7-34.79%), and hexadecyl acetate (4.9-9.4%), representing different responses to fertilizers. To sum up, the best fertilizer to improve the yield of saffron was manure followed by floral and delfard.

The use of agricultural practices such as plant density and environmental friendly fertilizers are effective in improving plant products. This study was conducted to determine the physiological and biochemical response of Bakhtiari savory (Satureja bachtiarica Bunge.) to cattle manure (30-ton ha-1) and plant density (high plant density, HPD: 80000, medium plant density, MPD: 40000, and low plant density, LPD: 26666 plant ha-1) during 2018 and 2019. Chlorophyll (Chl) content, relative water content (RWC), Malondialdehyde (MAD), proline concentrations, total phenol content (TPC), total flavonoid content (TFC), and essential oil (EO) percentage of Bakhtiari savory were measured under dryland farming condition. Chl a and b increased under manure application at high/MPD in the second year. RWC at high/MPD with manure application in the second-year plants was higher compared to other experimental treatments. The highest MAD was observed in plants at LPD with non-manure application in the first year. Increased proline concentration was found at LPD compared to MPD and HPD. TPC and TFC in second-year plants were significantly greater than the first-year plants. Organic fertilizer improved TPC and TFC content. The greatest TPC and TFC were observed at MPD with manure application in the second-year plants. EO percentage in MPD was higher than other plant densities. The highest EO percentage was achieved at MPD with manure application in the second-year plants. It could be suggested that use of cattle manure and HPD or MPD leads to obtain higher plant production.

Cultivation and establishment of perennial medicinal plants in the low-yield dryland farms and degraded rangelands can prevent the erosion caused by annual repeated plowing, and create changes in the conservation and restoration of dryland agricultural ecosystems. To prove this hypothesis, several experiments were conducted in the form of a national plan in seven key dryland areas in North Khorasan, Guilan, East Azarbaijan, Kurdistan, Kermanshah, Isfahan, and Tehran during 2007-2011. Field experiments were carried out in a split-plot design, containing species as main plot at 10 levels (10 Thymus species) in different areas, and density as subplot at three levels (4, 6 and 8 plants per square meter). The results of field experiments in different years and different provinces revealed the establishment of all species studied under rainfed conditions. The highest dry matter yield in Thymus daenensis (2994 kg ha-1) and T. kotschyanus (2884 kg ha-1) was recorded for Kurdistan, Kermanshah, and Tehran at a density of eight plants per square meter. The oil yield varied from 0.69-3.11% in different treatments. The highest oil percentage was obtained for T. daenensis in Kermanshah and Kurdistan. According to the results, the increased dry matter yield at high density under rainfed conditions of Kermanshah, Kurdistan, and Tehran indicates the high production capacity of thyme under rainfed conditions with an annual rainfall up to 400 mm and in cold semi-steppe regions. The highest amount of thymol (80.33%) and carvacrol (71.9%) was recorded for T. daenensis and T. kotschyanus in Damavand. Results indicate the appropriate establishment and yield of local thyme species under rainfed conditions that could be introduced as perennial medicinal plants for dryland farming.