ارزﻳﺎﺑﻲ ﺻﻔﺎت ﻣﻮﻓﻮﻟﻮژﻳﻜﻲ ﺳﻪ رﻗﻢ ﺑﺮﻧﺞ ).Oryza sativa L( ﺑﻪ ﺳﻄﻮح ﻣﺨﺘﻠﻒ ﻧﻴﺘﺮوژن در دو ﻧﻈﺎم ﻛﺸﺖ ﻏﺮﻗﺎﺑﻲ و ﻫﻮازی ﺗﻐﻴﻴﺮ ﻳﺎﻓﺘﻪ

This research was designed to evaluate the response morphologic parameter of three rice cultivars to different nitrogen rates in two rice system lowland and modified aerobic in 2013. The experiment arranged in factorial split block randomized complete block design with three replicates at Sari Agricultural Sciences and Natural Research University. Main plots were two cultivation system lowland and modified aerobic and subplots were two factorial of nitrogen at four levels (0, 40, 80, and 120 kg N/ha) and rice cultivars (Tarom, Keshvari, and Pajhohesh). Results of ANOVA showed a significant interaction between cultivation system and nitrogen in terms of root length and root dry weight and also interaction between cultivar and nitrogen in term of all mentioned parameters. In modified aerobic system root length increased when nitrogen applied to up 80 kg/ha and then decried. The maximum root dry weight, however, observed nitrogen 120 kg N/ha. Shoot root dry weight ratio in lowland system increased linear from 0 to 120kg/ha while in modified aerobic system increased when 80 kg/ha nitrogen was applied and then declined. The highest paddy yield was belonged to Keshvari cultivar in 80 and 120 kg N/ha treatments (nearly 700 and 730 kg/m2, respectively). In conclusion, it seems that change in cultivation system from lowland to modify aerobic could be effective to meet suitable yield less water consumption.