Mandana Tayefe, Ebrahim Amiri, and Azin Nasrollah Zade In The Name Of GOD Effect of nitrogen management on nitrogen uptake, dry matter production and some yield parameters Mandana Tayefe, Ebrahim Amiri, and Azin Nasrollah Zade

Islamic Azad University – Lahijan Branch Introduction RICE (Oryza sativa L.) is one of the most important cereal crops of the world, grown in wide range of climatic zones. Nitrogen (N) is the most important nutrient in irrigated rice production. It is the most yield-limiting nutrient in irrigated rice production around the world. Islamic Azad University – Lahijan Branch

Islamic Azad University – Lahijan Branch Introduction Nitrogen contributes to spikelet production during early panicle formation stage, and contributes to sink size during the late panicle formation stage. Nitrogen also plays a role in grain filling, improving the photosynthetic capacity, and promoting carbohydrate accumulation in culms and leaf sheaths Use of N fertilizers in adequate amount, form and methods of application are important management strategies of this element. Nitrogen use efficiency has been defined in various ways, but these definitions generally take into account quantity of N accumulated in the plant, known as uptake efficiency and quantity of N utilized in grain production known as utilization efficiency. Islamic Azad University – Lahijan Branch

Islamic Azad University – Lahijan Branch Introduction The present investigation was undertaken to have a detailed account of the effect of commercially-available nitrogenous (N) fertilizers (Urea) on the nitrogen uptake, dry matter production, yield and some yield components of commercial rice varieties in Iran. Islamic Azad University – Lahijan Branch

Islamic Azad University – Lahijan Branch Materials and Methods The field experiment was conducted at Rice Research Institute, Rasht, Guilan, Iran, during the growing season. The experiment was laid out in randomized complete block design with three replications. 4 nitrogen fertilizers levels: (N1: without fertilizer, N2: 30 kilogram per hectare in one division during transmission of seedling from nursery to the main field, N3: 60 kilogram per hectare in two divisions during relocation of seedling from nursery to the main field and tillering(30 days after transmission), and N4: 90 kilogram fertilizer per hectare in two divisions at the time of transferring seedlings from nursery to the main field and in clawing stage). Islamic Azad University – Lahijan Branch

Islamic Azad University – Lahijan Branch Materials and Methods Three different varieties were examined (Hashemi: v1, Alikazemi: v2 and khazar: v3). The N fertilization was applied as single incorporated application of urea (46% N). Three hills in each plot were randomly selected and tagged for recording plant height(cm), tillers/m2, punicle/m2 at harvest (95 days after transplanting). The net plots area were harvested and dried for 2 days at 70o c.Grain weight, adjusted to 14% moisture content, was used as estimates of grain yield (kg/ha). Islamic Azad University – Lahijan Branch

Islamic Azad University – Lahijan Branch Materials and Methods The net plots area (6 m2) were harvested and dried for 2 days at 70o C. Grain weight, adjusted to 14% moisture content, was used as estimates of grain yield (kg ha-1). Grain nitrogen concentration was determined by the methods of micro-Kjeldal digestion, distillation, and titration. The data were analyzed statistically with MSTATC and SAS software were used in variance analysis and comparison of average. Islamic Azad University – Lahijan Branch

Results and Discussion Nitrogen fertilization and variety had significant effects on grain yield. Source df Grain yield (kg/ha) Year 1 ns R 4 N 3 ** V 2 * N*V 6 Error 44 - cv Islamic Azad University – Lahijan Branch

Results and Discussion Maximum yield (3662 kg/ha) was obtained with the higher N rate (90kgN/kg) with detecting yield decrease in the range of rates tested . Islamic Azad University – Lahijan Branch

Results and Discussion In his research presented that dry matter accumulation increased significantly with N fertilizer application in rice at all the growth stages of the crop. Also total biomass due to Khazar variety was higher than other varieties (7734 kg ha-1). Findings showed that N4 (90kgN/ha) caused higher panicle density (235.8/m2) (table2) .Also variety had significant effects on panicles m-2.As Hashemi variety had the highest panicles m-2 (235.9 m2). Differences between N rates due to total grains per panicle were not significant .Also variety had significant effect on total grains per panicle .As Khazar variety had the highest total grains per panicle (161) . Islamic Azad University – Lahijan Branch Variable total biomass (kg/ha) Yield (kg/ha) panicle/m2 Total grains per panicle 2008 7504a 3069a 217.66a 110.27a 2009 5860b 2911a 194.97a 102.63b N1 5032d 2194c 179.33c 108.6a N2 6241c 2749b 192.722bc 107a N3 7169b 3356a 217.333ab 106.2a N4 8386a 3662a 235.889a 103.8a V1 5973b 2663b 235.917a 78.25b V2 6339b 2893b 224.500b 80.04b V3 7734a 3414a 158.542c 161a

Results and Discussion Results could also explain the lower yields for Hashemi variety, considering the high correlation between total dry matter production and grain yield (R2 = 0.73 and 0.91 and 0.99 (first year) and R2 = 0.90 and 0.95 and 0.99 (second year) for Khazar, Kazemi, Hashemi respectively. Islamic Azad University – Lahijan Branch

Results and Discussion Grain N-uptake increased significantly with N .In the other hand, the highest grain N-uptake was due to Khazar variety. Khazar variety accumulated maximum N (52.41 kgha−1) in the grain. N4 (90kg N ha-1) caused the highest content of straw N uptake (57.16 kg ha-1). In N4 treatment (90 kg N ha-1), the highest straw-N uptake was observed (22.16 kg ha-1) and the lowest content (12.61 kg ha-1) belonged to N1 (0 kg N ha-1). Straw N-uptake increased with nitrogen increasing, significantly. But result of variance analysis at 1% confidence level revealed that nitrogen uptake in straw had no significant response to variety . Result of variance analysis at 1% confidence level revealed that nitrogen uptake in total had a significant response to N fertilization. N4 treatment (90 kg N ha-1) caused the highest total-N uptake was observed (79.38 kg ha-1) and the lowest content (45.77 kg ha-1) belonged to N1 (0 kg N ha-1). Total N-uptake increased, as nitrogen fertilizer increased, significantly. Result of variance analysis at 1% confidence level revealed that total nitrogen uptake had significant response to variety .As Khazar variety produced highest nitrogen-N uptake (71.54 kg ha-1), Also the lowest content of total-N uptake belonged to Hashemi variety (57.37 kg.ha-1).

Islamic Azad University – Lahijan Branch CONCLUSIONS Total biomass (8386 kg/ha), grain yield (3662 kg/ha), panicles m-2 (235.8) and total grain per panicle (103.8) were reached the highest value at high nitrogen level. Among the varieties the highest total biomass (7734 kg/ha), grain yield (3414 kg/ha) and total grain per panicle (78.2) belonged to Khazar. Dry matter, total N uptake was varied in different cultivars significantly and Khazar variety had the highest contents. Total biomass and total N uptake was varied significantly with the increasement of the amount of nitrogen applied. As total biomass and total N uptake increased with increasing in N fertilizing. This information could be useful for genetic improvement programs under development, and to select management practices that increase yield and N use of applied fertilizer. Islamic Azad University – Lahijan Branch

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