Evaluation of Chemical and Organic Nutrition Systems onYield and Water Use Efficiency in Rice (Oryza sativa L.) Cultivars under low Irrigation stress Conditions

In order to investigate the effects of chemical and organic nutritional systems on yield, water utilization in rice cultivars under irrigation stress, a split Plot factorial experiment was conducted in a randomized complete block design with three replications at Dasht-e Naz Agricultural Company, located in the city of Sari in 2016 Irrigation stress treatments were performed in three levels: the stress at the time of the beginning of the tillering (15 days after the installation of the work), the developmental stage of the transfer (the end of flowering and grain filling start) and the lack of stress (controls) as the main factor, through irrigation cut and irrigation again after the appearance of surface cracks The type of feeding system was considered in four levels of Vermicompost and compost azolla (6 and 8 t.ha-1 respectively), humic acid (4.5 L.ha-1) and the common chemical fertilizers Nitrogen, Phosphor, Potassium and cultivars were considered on two levels (Shirodi and local Tarom) in factorial form as a subagent The results variance analysis showed that there was a significant difference between Shiroudi and Tarom cultivars in terms of rice paddy yield in different levels of irrigation stress and nutritional systems. Under common irrigation conditions, the most biological functions of Paddy yield in the varieties of Shirodi and local Tarom, was obtained 6577.9 and 3776.4, Kg.ha-1, Respectively. Low irrigation stressin the developmental stage of the beginning of the tilleringreduced the rice paddy yield by 6.87 and 1.67 andin the remobilization stage, reduced the rice paddy yield by 17.65% and 2.97%, compared to non-stressed conditions With application of humic acid nutrition system, improvement of rice yield was observed in Shiroudi (6563.1 Kg.ha-1) and local Tarom (3878.77 Kg.ha-1) in compared with other nutrition systems.by using the humic acid, azolla compost and Vermicompost in Shirodi variant, the rice paddy yield increased 16.12, 9.02 and 3.62 Percent and in local Tarom 7.85, 3.47 and 2.21 percent respectively, compared with the chemical fertilizer. The highest Water Use Efficiency in the cultivars was observed with the average of 0.1050 and 0.8016 Kg/m3No rainfall, outlet runoff and tillage water were observed under conditions of non-stress. Totally, the results showed highest yield of Paddy was obtained for both Shirodi and Tarom cultivars under non-stress conditions in the humic acid nutrition system.