جستجوی مقالات مرتبط با کلیدواژه "سرعت رشد گیاه" در نشریات گروه "آب و خاک"

One of the ways to reduce the use of chemical fertilizers and increase sustainability in rice cultivation is the correct application of irrigation water and cultivated cultivars. This research is conducted with the aim of the effect of irrigation management and different levels of phosphorus fertilizer on the yield and some agronomy traits of rice in Hashemi and Guilaneh cultivars in Guilan province.

This experiment was done in the form of split-split plots under a completely randomized block design with three replications during the years 2017 and 2018 in the research farm of the Islamic Azad University, Lahijan Branch, located in the village of Kateh-Shal (in the latitude of 37°12° N and longitude of 50°01E° with an average height of 34.2 meters above sea level). The treatments studied in this research included cultivar (Hashemi and Guilaneh rice) as the main factor, irrigation intervals (continuous flooding, alternating with an interval of 5 and 10 days) as a secondary factor, and the amount of phosphorus chemical fertilizer of triple superphosphate (50, 75 and 100 kg/ha) was as a sub-sub-factor.

The results showed that the solo effects of the factors and the interaction effects of their two and three factors were on paddy yield and relative leaf water at the level of 1% and on the chlorophyll index at the level of 5% significant. According to the interaction effect of irrigation management and fertilizer consumption and cultivars, the highest yield of paddy in the first year was 5362 and 5104 kg/ha in Guilaneh cultivar with irrigation intervals of 5 day and fertilizer levels of 50 and 100 kg P/ha, in the second year, Guilaneh cultivar with irrigation intervals of 5 day and fertilizer levels of 50 and 100 kg P/ha, an average of 5355 and 5104 kg/ha was obtained, respectively. The highest relative leaf water in the first year was in the Guilaneh cultivar and irrigation intervals of 5 day with fertilizer consumption of 50 kg P/ha with an average of 0.64, and in the second year was in the Guilaneh cultivar in irrigation intervals of 5 day and fertilizer levels of 100 kg P/ha with an average of 0.66. Based on the interaction effect of irrigation management, consumption fertilizer and cultivars, the highest chlorophyll meter in 2017 was in the Guilaneh cultivar with irrigation intervals of 5 day and fertilizer levels of 50 kg P/ha with an average of 41.7. In 2018, the highest chlorophyll meter was obtained in the Hashemi cultivar and under flooding management with 50 kg P/ha fertilizer, with an average of 40.7. The highest leaf area index in 2017 and 2018 were observed in Guilaneh cultivar with irrigation intervals of 5 day and 75 kg P/ha fertilizer, with an average of 4.2 and 4.4, respectively.

The Interaction effects of irrigation, fertilizer and cultivar in the studied years was showed that in Guilaneh and Hashemi cultivars, the highest yield of paddy were at fertilizer levels of 50 and 100 kg P/ha. Based on the results and with the criterion of rice yield, the use of the Guilaneh cultivar with in irrigation intervals of 5 day and fertilizer levels of 50 and 100 kg P/ha is suggested as the most suitable conditions for the study area.

Deficit irrigation is a suitable method for obtaining the economic and acceptable yield with the minimum amount of water (Zegbe et al., 2004). Although the yield in unit area is decreased in this irrigation method, the amount of consumption water, water harvesting, delivery and distribution costs of water decreased, which results in more benefit (Yazar et al., 2009).Partial root drying (PRD) is the modified method of deficit irrigation which some part of plant roots is irrigated and another part of them are placed in dry soil. For the first time, the concept of PRD was applied by Grimes et al. (1968) in the United States. In this method, water uptaking from the wet zoning of plant roots holds the water status in plant in a favorable condition (Davies et al., 2002), and the other part of roots placed in dry soil results in increasing abscisic acid hormone production.The most important growth indices which are used frequently in plants include leaf area index (LAI), crop growth rate (CGR) and relative growth rate (RGR) so that plant production dry matter can be investigated using these indices (Modarresi et al., 2004). Investigation of variations of growth indices of five maize hybrids under two different irrigation regimes indicated that interrelationship between leaf area index and grain yield was significant (Nori Azhar and Ehsanzadeh, 2007).Water scarcity is one of the most important factors that decrease the maize yield and yield reduction depending on corn cultivars and growth stages that are affected by water stresses. With regard to desirable features of leafy and commercial hybrids of maize and also different effect of stresses in different stages of vegetative and reproductive growth, the objective of this study was to investigate the effect of water stress and new deficit irrigation strategies on growth indices of two corn cultivars in Kashmar climate.