جستجوی مقالات مرتبط با کلیدواژه "drainage" در نشریات گروه "زراعت"

The present research was conducted in order to achieve the best method of planting and obtaining the maximum yield of flowers and stigmas of saffron (Crocus sativus L.) in two stages in Sari Plain. The first stage was carried out in the research farm of Sari Agricultural Sciences and Natural Resources University during 2021-2022 as split plots on randomized complete blocks design with three replications, in which the experimental treatments included drainage depth (15, 30, and 45 cm) in the main plots and three drainage distances (50, 100 and 150 cm) in the subplots. In the second stage, the produced corms were stored for three months in the incubation environment, and then, the corms were transferred to two different environments of aeroponic and field to evaluate saffron's flower and stigma performance. The measured traits included the number of produced flowers, average flower weight, dry stigma weight in both field and aeroponic, and the amount of safranal, picrocrocin, and crocin and in aeroponic conditions. The evaluation of reproductive traits of saffron under aeroponic showed that with increasing the depth of the drain and decreasing the distance of the drain, traits such as the number of flowers, flower weight, and stigma dry weight increased; when the maximum value of these traits, equivalent to 4744 flowers.m-2, 1423 g.m-2, and 10.7 g.m-2 were observed at 30 cm drainage depth and 100 cm drainage distance, which did not have a significant difference with 45 cm drainage depth treatment and 100 cm drainage distance. In addition, the results showed that the amount of picrocrocin decreased with increasing the depth of the drain and the distance of the drain. In addition, no significant difference was observed between different treatments for crocin content. Comparing the reproductive traits of plants under two cultivation conditions, namely air, and field, revealed a reduction of 21%, 20%, and 12% in the number of flowers, fresh flower weight, and dry weight of stigma, respectively, within the field conditions. In summary, the findings suggest that, for optimal saffron production in coastal areas, the propagation of corms in the field at depths of 30 cm and 100 cm with proper drainage, followed by flowering of the propagated corms through aeroponic cultivation, could be a viable and economically sound approach for one-year saffron cultivation in the Sari plain region.

Bulrush is one the most important weed of paddy rice. Pot and lab experiments were carried out in order to study some of its ecophysiological characteristics. In the first study, the effects of soil moisture (6, 12, 24, 34 percent based on soil dry weight, and permanent flood as control) on overwintering of bulrush tubers and its growth in following year was determined. In the second experiment, the cardinal temperatures required for tubers germination was investigated. The results showed that survival and overwintering of bulrush tubers in 6, 12 and 24 percent moisture was 10, 30 and 82 percent respectively, and fell sharply in higher humidity. In addition, the number and fresh weight of tubers and also length and fresh weight of bulrush rhizomes in 6% moisture was 100, 58, 70 and 92 percent lower compared to field capacity treatment (24 percent moisture level). The maximum germination occurred at 25 to 30 degrees Celsius and the minimum germination at 40°C and the highest germination rate in 30°C. By considering the low survival rate and a considerable reduction in vegetative organs of bulrush in low soil moisture, drainage and tillage of paddy fields after the rice harvesting is a means of reducing overwintering populations and management of this weed. Minimum temperature required for germination of bulrush, compared with rice growing base temperature (12°C), and the growth of bulrush before transplanting rice, indicates well adoptability of bulrush to paddy rice ecosystems and the need to provide appropriate integrated solution for its management.

The objective of this study was to determine the allowed and desired limits for heavy soils of texture (clay loom)، as it has operational capability (friability)، These limits were 6. 34 mm for planting and 10. 62 mm for harvesting in each raining or irrigation episode. We determined some factors that affect soil wetness and water content as follow: the amount and severity of rain، the condition of soil’s drainage، the percent of air moisture، evapotranspiration، the amount of runoff، the amount and severity of sunlight، the ambient temperature، the condition of vegetation and، the soil texture. The time needed for dryness and removal of soil moisture as evapotranspiration in each over- desired and allowed capacity rains are 5-7 days. Also، because of higher evaporation in planting time (late April and early May) than in harvesting time (November)، and also higher surface temperature in spring، both result in moving the vapor from deeper layers of soil to surface. Therefore، as our result showed، the time needed for readiness of soil for machinery operation at time of planting are 5 days for planting (late April and early May) and 7 days for harvesting time (November). According to our calculation، 19. 5% of rains at planting time and 7. 5% at harvest time changed to run- off; and with taking this amount of run- off in account at allowed- limit calculation، and also because of texture of the studied soil، the maximum allowed rain in which the soil remains in proper condition for machinery planting and harvesting activities exceeded 7. 6 and 11. 41 mm in each rainy day. As a result، according to limiting factor of well doing of operations and also factors affecting these restricting factors، the number of working days for mechanized planting operation was found to be about 19. 69 days and also 21. 98 days for harvesting operations in farms with heavy soil with 98% of probability.