جستجوی مقالات مرتبط با کلیدواژه « Yield » در نشریات گروه « محیط زیست »

Forage plants are of undeniable importance in grazing livestock and thus supply human needs for livestock products. Unfortunately, in Iran, the production and management of forage plants is less considered than other crops. As a result, on the one hand, the lack of attention to increase the quantity and quality of forage, has led to a shortage of meat and dairy products and reduce their quality, and on the other hand due to livestock pressure on natural pastures has led to the destruction of a large part of vegetation. Therefore, paying attention to the cultivation of forage plants with the scientific method in the country, which is faced with uncontrolled population growth and lack of rich rangelands, is of particular importance. Forage production is very important in the country. Examining different rangeland and forage species under different environmental stresses, especially salinity stress, recognizing the potential for species adaptation and introducing compatible species, can be a step towards eliminating forage shortages. Existence of huge resources of water and saline soil in the country has made the use of salinity-resistant plants as new sources in order to produce sustainable forage to meet the nutritional needs of livestock in the country inevitable. Creating new water sources for irrigation saves drinking water for human consumption. Haloculture is a method of using saline water and soil resources in agriculture and one of the salinity rings is the production of plants with saline water resources. Caspian Sea water with less electrical conductivity than the water of other open seas of the world with an average of 18.5 ds / m equivalent to 12000 ppm can be used as an unlimited water source for to be evaluated in rangeland crop cultivation. Also, due to the presence of many useful salts in the Caspian Sea water, including potassium, calcium and sodium, compared to drinking water, it can be used as a suitable water source for growing forage plants. The average salt in the Caspian Sea is about 13 grams per liter while in the high seas and oceans it is about 45-35 grams per liter. The Caspian Sea has the lowest amount of Cl- and Na+ and the highest amount of Ca2+ and so42- compared to other high seas, which in turn causes less damage to the physical and chemical properties of the soil. Therefore, the use of Caspian Sea water for agricultural purposes is considered as a viable option. In this regard, we studied the effect of seawater irrigation at five levels of zero (control), 10, 20, 30 and 50% mixed with fresh water cultivated in the spring of 1399 on two plants Agropyron elongatum and Festuca arundinacea.MethodologyThis research was conducted on arable land in Larim village in Mazandaran province in the spring of 1399. Larim in terms of geographical location with a longitude of 50 to 52 degrees and 56 minutes and a latitude of 36 degrees and 43 minutes to 45 degrees is located in the northern margin of the city of Joybar from the Gilkharan section (Figure 1). It is located at a negative height of 20 meters above the sea level. This village is connected to the Caspian Sea at a distance of 4 km from the north. (Rastegar et al., 2017). In order to evaluate germination rate, percentage and index, fresh and dry weight of aerial and underground organs, root and stem length and production, percentage of potassium, sodium, nitrogen, protein and percentage of relative relative humidity in the form of block design. Random complete in split plot with three replications and five salinity levels (fresh water and 10% ratio equal to 1200 ppm, 20% equivalent to 2400 ppm, 30% equivalent to 3600 ppm and 50% equivalent to 6000 ppm Caspian Sea water prepared from Larim coast) Was done by planting in a plot of land with 60 plots of one square meter in Larim area. The water quality characteristics of the Caspian Sea and the water used for dilution and soil properties of the region were studied in the soil and water laboratory of Joybar city (Tables 1 and 2).Also, having the data of dry weight and area of each plot, by multiplying the amount of calculated dry weight (grams per square meter) by 10, the amount of production in kilograms per hectare was calculated. Finally, the data were analyzed by analysis of variance and the comparison of mean traits in LSD treatments was performed in Spss software version 25. ConclusionThe results of analysis of variance showed that most of the studied parameters of both species under different salinity levels of Caspian Sea water in different proportions include: fresh water (control), 10% Caspian Sea water, 20% Caspian Sea water, 30% sea water Caspian and 50% of Caspian Sea water were examined, showing a significant difference at the level of 1% (P≥0.01) (Table 3). The two rangeland species studied were evaluated together at different salinity levels. The results of germination percentage of two species under different salinity levels showed that the highest germination percentage with 100% was for both species that did not show a significant difference with each other. The results of Maguire index germination rate showed that Festuca species under normal water treatment and 10% salinity of sea water with a value of 4.94 both had the highest germination rate which did not show a significant difference with each other but with Agropyron species. They showed significant differences at different salinity levels. The results of germination rate of Thomson index showed that Festuca species under normal water treatment with 12.38 had the highest germination rate that there was no significant difference between different species but with Agropyron species at different salinity levels. The results of germination rate coefficient showed that Festuca species under control treatment with 66.23 had the highest value, which showed a significant difference with different salinity levels in Agropyron species. The results of average daily germination showed that Festuca species under control treatment and 10% and 20% of sea water with the value of 10.74 had the highest value and with Agropyron species, showed a significant difference in all salinity levels. The results of germination index showed that Agropyron species under normal water treatment with the value of 10.44 had the highest value, which showed a significant difference with 30 and 50% levels of Agropyron and at different levels of salinity with Festuca species. The stem lengths of the two species under different salinity levels were also examined. Accordingly, the maximum stem length for Agropyron species under treatment was 10% with 67.23 cm, which except for the treatment of 20% seawater in Agropyron species with other levels of this species and also with different salinity levels in Festuca species showed a significant difference. The results showed that the maximum root length for 10% sea water treatment was 18.25 cm in Agropyron species, which showed a significant difference with other salinity levels in Agropyron species and different salinity levels of Festuca species. The highest fresh and dry weight of shoots for Agropyron species treated with 20% salinity of sea water with 1422.96 and 256.13 g, respectively, which was a significant difference with other different salinity levels in Agropyron species and with different salinity levels in Festuca species. The results of fresh and dry weight of roots showed that Agropyron under normal water treatment with 264.49 and 31.73 g, respectively, had the highest weight, which was a significant difference with other treatments in Agropyron and all different salinity levels in Festuca species. The production results showed that 20% treatment for Agropyron species with 2561.30 kg / ha had the highest value, which except for 30% treatment for Agropyron species with other salinity levels related to Agropyron and all salinity levels of Festuca showed a significant difference. Is. The lowest production for Festuca species was treated with 50% salinity of seawater. The results related to the amount of sodium in the plant showed that Festuca species under the treatment of 50% seawater with 0.63% had the highest value and showed a significant difference with other treatments of both species at all salinity levels. The results related to the amount of potassium showed that Agropyron species under normal water treatment had the highest value with 19.53% and showed a significant difference with other treatments of both species at all salinity levels. The results related to the amount of nitrogen and protein showed that Agropyron species under normal water treatment had the highest values with 2.70 and 16.87%, respectively, and in both species with 20, 30 and 50% salinity treatments showed a significant difference. The results related to the percentage of relative humidity showed that Agropyron species under ordinary water treatment had the highest value with 71.58% and showed a significant difference with the treatments of Festuca species in all salinity levels. The results of analysis of variance of the studied factors of the two species are shown in Table 3 and the average comparison of the studied parameters is shown in Figure 2.

Temperature is one of the factors affecting plant growth. Hence, in this paper, future temperature trends in Abhar region affected by climate change during future periods was evaluated and compared with the period of observation. Plant yield in the future and different cultivation periods was later simulated and estimated through AquaCrop simulation model of plant yield. The study observation period was considered as 1986-2010 AD, near horizon 2011-2045, the average horizon 2046-2079 and 2080-2100 horizon in the current study. LARS-WG software was used in HadCM3 model and A2 scenario in order to downscale the results of general atmosphere circulation's simulation model. Furthermore, the scenario file was generated in this study. According to the results obtained, the highest yield wil be cultivated on May 26 with 46.29 tons per hectare and the lowest yield will be produced on June 5 with 40.6 tons per hectare. If we change the traditional cultivation time from May 15 to May 26, a growth of 0.28 tons per hectare will be expected. The highest yield will be on May 15 in the future. Moreover, the sorghum's yield will decrease. Lesser photosynthesis during the shorter growing season and C4 photosynthetic system of this product could be involved in this yield loss.

Population growth, industrial development, low water use efficiency, and reduced precipitation have resulted in over-extraction of groundwater. Planning to change the patterns of water consumption in all aspects of household, industrial and agricultural uses has become increasingly important. The use of drought tolerant plants with a low water requirements and high water use efficiency is among the practical ways in the agriculture sector. The use of perennial species is recommended to increase rainfall storage, and prevent land degradation, water and wind erosion, and flood. Saffron (Crocus sativus L.) with a very low water requirement, a dormancy period from late spring to early fall, and ability to adaptation to the climatic conditions of the area, is a plant suitable for planting in the Damavand area. According to the results, 0.6 and 0.87 Kg ha-1 dry stigma was obtained from planting about 2.7 ton corms per hectare in the first and second year, respectively. The highest yield of saffron is obtained from the third year onwards. Due to the lack of water resources, dry farming and planting the species with low water requirements could be a good solution to preserve agricultural lands, prevent soil erosion, and reduce the migration of farmers.

In order to investigate the effects of nitrogen fertilizer amount and its spliting on rice (Hashemi variety) yield and nutrients uptake from urea source, was conducted in the National Rice Research Instituteduring during a two- year experiment. The study has been done based on a Randomized Complete Block Design (RCBD) with three replications. Increasing amount of nitrogen fertilizers based on urea source in four categories was as the first factor, i.e. 30, 60, 90, and 120 kg nitrogen ha-1 and the time of its application was as the second factor i.e. basal application at transplanting, two splits i.e. at transplanting and at the beginning of tillering, and three splits i.e. at transplanting, at the beginning of tillering and just before flowering. Results showed that yield and nitrogen uptake by grain and straw increased significantly by applying of increased amount of urea fertilizer and when the fertilizer was used in two or three splits application (P

Clary sage (Salvia sclarea L.) is one of the most important aromatic plants, cultivated worldwide, and is used in flavor and fragrance industries due to its valuable essential oils. In this experiment, carried out in Semnan province during 2005 to 2009, a native Salvia sclarea L. was evaluated for its suitability to be cultivated in arid and semi-arid areas. The seeds of S. sclarea were collected from its natural habitat in the north of Semnan. The seeds (6 kg/h) were sown directly in the fields during the spring. At full flowering stage (in the second year of cultivation), the plants were evaluated for growth parameters and the essential oil yield of inflorescences. The comparison between the natural and agro ecosystems showed that plants in the semi-arid agro ecosystem had the highest plant height, flowering branches, leaf area, total fresh flower yield (8.25 ton/h) and essential oil yield (10 kg/h). The yield of clary sage ecotype cultivated in semi-arid area of Semnan was extremely higher than that of natural habitat. As a whole, the native ecotype of S. sclarea could be an alternative crop with significant economic value to be cultivated in semi-arid conditions.

Toxic heavy metals from pollutants stable non-biodegradable, which can be in the environment, water and soil, and as plant absorption and thus enter the food chain, so for each of the heavy metals limit is set higher it can be toxic and dangerous. Heavy metal pollution not only directly affects the physical and chemical properties of the soil, reduce biological activity and declining access Zesty nutrients affect soil but also to human health from entering the food chain and environmental security through the influence of water underground it is dangerous. Cadmium is a heavy metal and environmental pollutants from various sources such as fertilizers and soil into the human food chain. In order to improve soils contaminated with heavy metals, the use of zeolites has been reported by several researchers.
An experiment to investigate the effect of zeolite stands on cadmium uptake and dry matter weight of the cucumber tree was designed. This experiment factorial experiment design randomized complete block design with 2 treatments zeolite (four levels of zero, 1, 2 and 3 tonnes per hectare) and cadmium (five levels, 3, 6, 9 and 12 mg kg) with three replications.
The results showed that with increasing zeolite application of cadmium concentration in cucumber tree fell, and the largest decline in the level of 3 tons per hectare, so that the level of consumption of dry matter yield also increased.