Effect of Irrigation Management and Phosphorus Fertilizer Levels on Yield and Some Agronomic Traits in Two Rice Cultivars

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.