Measurement of Water Consumption of Promising Rice Cultivars Using Mini-Cylindrical Lysimeters in Amol City

Rice is one of the most important agricultural products in the world. Rice cultivation in Iran has great economic and social importance. Mazandaran province is one of the most important rice production centers in Iran, accounting for 44% of the Iran's rice production. Due to the high consumption of water in the agricultural sector, the optimal use of water resources in agriculture is necessary.The water required by rice is directly related to evapotranspiration. The most reliable method of calculating evapotranspiration is using a lysimeter. The purpose of this experiment is to calculate the evapotranspiration of different varieties of rice using mini-lysimeters and to introduce the best variety for cultivation.

The experiment was conducted as randomized complete block design with three replications and eleven treatments, at Rice Research Institute of Iran (Amol) during the 2020. The treatments included different rice varieties in 11 levels T1: AR2, T2: AR6, T3: AHS, T4: DAH, T5: 1117, T6: 952, T7: 956, T8: E104, T9: S715, T10: Tarom, and T11: Shiroodi. Mini lysimeters with open bottom and closed bottom had a diameter of 60 cm and a height of 50 cm. Field soil was sampled from 0 to 30 cm depth and studied in the laboratory. The date of transplanting was similar in all rice cultivars The planting density of seedlings was 20×20 cm and 7 seedlings were placed in lysimeter. The lysimeters were placed 6 cm above the ground in the soil. The seeds were planted in a treasury and the seedlings were placed in the lysimeter after 30-35 days (after 3-4 leaves and height 25-20 cm). Water management in lysimeters was in the form of flooding (5 cm). Finally, variance analysis of the obtained data was done using SAS software and the mean of the treatments were compared through the least significant difference (LSD) test at 5% probability level.

The results showed that different varieties and lines of rice was effective on infiltration, evapotranspiration, yield, water consumption and were statistically significant at 1% level of probablity. The highest and lowest evapotranspiration with averages of 4938.7 and 3747 m3/ha belonged to T9 and T5 treatments, respectively. The highest and lowest yields with averages of 7773.7 and 2938.1 kg/ha belonged to T8 and T6 treatments, respectively. The highest and lowest values of deep percolation were observed with averages of 303.3 and 185.3 mm in T9 and T5 treatments, respectively. The highest and lowest amount of applied water with averages of 9972 and 7600.3 m3/ha belonged to T9 and T5 treatments, respectively. The highest and lowest water productivity with averages of 0.98 and 0.3 kg/m3 were related to T8 and T9 treatments, respectively. The results showed that the length of the plant growth period was different in the tested cultivars and lines and it was effective on the amount of water consumption..

Finally, in the normal conditions of the region, line E104 is introduced as the best treatment due to the production of maximum grain yield, while in water shortage conditions, the line 1117 is recommended for planting due to less water consumption.