The Effect of Periodic and Flood Irrigation Methods on Yield and Irrigation Water Productivity of Rice in Amol City

many countries of the world, water shortage has become a serious and worrying issue. Studies show that the agriculture sector is the largest consumer of water resources in the world. Therefore, scarce of water resources is considered the biggest challenge of agricultural development and ultimately food security. Rice is the largest consumer of fresh water worldwide and in terms of importance, it is the second most important edible grain after wheat which constitutes the food of two-thirds of the world's population. Therefore, need to increase productivity to feed the growing population by using efficient water management practices and water saving technologies, water saving technologies. Due to the decrease in rainfall in Mazandaran province, The area of rice cultivation and its production has decreased. These conditions can cause irreparable damage to the large production of rice in the province and the subsistence economy of the rice farmers will suffer irreparable damage. For this reason, rice production in Mazandaran Province, which is very important strategically and economically, it is necessary to change irrigation management and traditional cultivation method to reduce the water demand for rice production.

The experiment was conducted in the form of a complete block-design with three replications and four treatments using, during the 2020 crop year in the Rice Research Institute of Iran-Amol. The selected rice variety was Tarem Hashemi. Treatments included conventional planting with periodic irrigation (T1), conventional planting with flood irrigation (T2), transplanting in un-puddled bed with flood irrigation (T4) and direct seed cultivation in dry bed with flood irrigation (T4). The number of experimental plots was 12 and the area of each was 30 square meters. Based on soil decomposition test and according to soil experts, Three types of phosphorus, potassium and nitrogen fertilizers were were used to all treatments. In two treatments, T1 and T2, the land was prepared with puddling, and in two treatments, T3 and T4, the field was plowed dry. Transplanting in puddled and un-puddled bed as transplants and in direct cultivation was germinated as seeds. In flood irrigation treatments, water flowed on the soil surface and The entire surface of the earth was flooded with a layer of water 5 cm high (with a 5-day irrigation cycle). In periodic irrigation treatments, after flooding the land, Irrigation was stopped and and after the water disappeared from the soil surface and after observing the first spot on the field surface, irrigation was done again (irrigation cycle 6-8 day). In this experiment, The exact volume of irrigation water was measured by installing volumetric meters in each of the experimental plots. Irrigation water productivity was calculated as the amount of yield produced per unit of irrigation water. 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 the level of five and one percent.

The results showed that the cultivation method was effective on yield, plant height, water consumption and irrigation water, water productivity and water use efficiency and was statistically significant at 1% level of probablity. The highest and lowest yields belonged to T2 and T4 treatments with 4079.2 and 2941.7 kg/ha, respectively. The highest and lowest irrigation water belonged to T4 and T1 treatments with 10301 and 6537 m3/ha, respectively. The highest and lowest irrigation water productivity belonged to T1 and T4 with 0.61 and 0.29 kg/m3, respectively. Based on the results of this experiment, The treatment of conventional planting with periodic irrigation (T1) did not have a significant reduction in yield compared to The treatment of conventional planting with flood irrigation (T2). The treatment of conventional planting with periodic irrigation (T1) saved irrigation water by 17% compared to the common cultivation treatment with flood irrigation (T2) and increased irrigation water productivity by 17% .Finally, the results of this research showed that there is no need to flood crete during the rice growth period. conventional planting system with periodic irrigation (T1) was chosen as the superior treatment and it can be a suitable alternative to the common cultivation system with flood irrigation of rice and a suitable option to deal with water shortages in recent years.