A split plots experiment based on randomized complete blocks design was carried out at field research center of Islamic Azad University, Shoushtar branch during 2012 to find out the suitable sowing date and Urea fertilizer used in Chamomile (Matricaria recutita). Main plots including three sowing date (9, 19 and 29 February 2012) and subplots including four levels of Urea fertilizers (5, 10, 15 and 20 g urea fertilizer per m-2). Delay at chamomile sowing date till 29 February decreased essential oil yield up to 50% compared 9 and 19 February sowing date. Increase of Urea fertilizer to 15 and 20 g m-2 increased essential oil yield to 47% compared use of 5 g m-2 Urea fertilizer. Results showed 9 and 19 February sowing date combined 15 and 20 g m-2 Urea fertilizer increase flower dry weight, flower essential oil percentage, flower essential oil yield and chamazolene percentage. Highest flower dry weight, flower essential oil yield and chamazolene percentage were obtained at 9 Februray plant sowing date + 15 g m-2 Urea fertilizer (38.4 g m-2, 0.36 g m-2 and 17.4% respectively) and 19 Februray plant sowing date + 15 g m-2 Urea fertilizer (36.2 g m-2, 0.34 g m-2 and 18.1%). These data did not have any significant difference with 9 and 19 February plant sowing date + 20 g m-2 Urea fertilizer. According to the results, the most suitable sowing date and Urea fertilizer for Chamomile in Shoushtar condition are 9 and 19 February and 15 g m-2 (150 kg ha-1) Urea fertilizer but it is advised this experiment repeat for multi years.

In the present study, the effect of urea fertilizer under pot and greenhouse cultivation on growth rate, total content of leaf terpenoids and bioactive compounds detectable by GC-MS was investigated in American agave leaf extract. Urea 46% fertilizer, with two concentrations of 5 and 10 g / l was used for irrigation, in 8-leaf stage and their effects were compared with plants irrigated with no fertilizer as control in a randomized complete block design. Addition of urea fertilizer with both concentrations increased the fresh and dry weight of leaves and roots. Urea fertilizer had no significant effect on leaf terpenoid content, but in terms of leaf extract analysis by GC-MS, had a positive effect on increasing the content of methyl palmitate and methyl stearate, which are valuable medicinal compounds with antimicrobial, anti-inflammatory, anti-cancer, and antioxidant properties. Utilization of urea fertilizer, doubled the percentage of these compounds in leaf extract. However, urea fertilizer reduced the content of bis(2-ethylhexyl) phthalate, which has also medicinal properties comparable to the two above mentioned compounds. The positive effect of urea fertilizer on a significant increase in octadecane and methyl palmitate (about twice) with usability as a biofuel is another important result of the present work.

Management of manure and chemical fertilizers application in the soil in terms of environmental impacts and performance of plants is important, especially in arid and semi-arid regions of Iran. A split plot experiment was carried out in a randomized complete block design with three replications at the research farm of Shahrekord University in 2014. Main factor was consisted of three levels of irrigation regimes including 100% (I1 or control), 75% (I2) and 50% (I3) of water requirement while 6 levels of manure application including 1) no amended fertilizer (control), 2) 25% urea fertilizer + 75% cattle manure 3) 50% urea fertilizer + 50% cattle manure 4) 75% urea fertilizer + 25% cattle manure 5) 100% urea fertilizer and 6) 100% cattle manure, were considered as subplot factor. Results showed that irrigation regime of I3 caused decreasing an contration of chlorophyll a, b and total, essential oil yield of flowering branch, leaf and stem while in caused 83 and 13.5 percent increase in the amount of carotenoids and proline compared to control, respectively. Fertilizer treatments, 25% urea fertilizer + 75% cattle manure, 50% urea fertilizer + 50% cattle manure, 75% urea fertilizer + 25% cattle manure, 100% urea fertilizer and 100% cattle manure caused significant increase in carotenoids content compared to control whereas the maximum carotenoids content with the average of 1.35 mg g-1 was obtained from the 25% urea fertilizer + 75% cattle manure treatment. A significant positive correlation was observed between chlorophyll a, b, total, essential oil percentage, essential oil yield of leaf and essential oil yield of flowering branches. Therefore, in order to obtain the maximum essential Moldavian balm under Shahrekord climatic condition, application of 50% urea + 50% cattle manure and full irrigation is recommended.

In order to investigate the effects of biological fertilizers application and various amounts of urea fertilizers under the water stress conditions on yield, nitrogen use efficiency, and effective ingredients of Calendula officinalis L., an experiment was implemented during the two cultivation years of 2015-2106 and 2016-2017. The study was conducted at the research farm of Islamic Azad University, Varamin-Pishva Branch. The experiment was performed in three replications as a split-split plot in a completely randomized blocks design. The experimental treatments included two levels of water stress as (the main factor): the absence of water stress (control) and irrigation cut off at the budding stage, as well as, four levels of biological fertilizers (as sub-factor) (no use), the application of Azotobacter (Chroococum), the application of Azospirillum (Brasilense), and combined application of Azotobacter and Azospirillum. Urea fertilizer sources were also classified (sub-factor) in four levels including no use (control), recommended amount of sulfur coated urea fertilizer (175 kg/ha of recommended amount of fertilizer), 75% of recommended amount of sulfur coated urea fertilizer (131 kg/ha), and the recommended amount of urea fertilizer without coating at 175 kg/ha. The results showed that irrigation cut off at budding stage resulted in reduced flower yield, biological yield, the amount of nitrogen, nitrogen use efficiency (crop efficiency), and nitrogen uptake efficiency. However, it resulted in the increased nitrogen use efficiency, α-cadinol, and morolol. In addition, in both years of experiment, the combined use of Azotobacter and Azospirillum, along with the recommended amount of sulfur coated urea fertilizer resulted in the increased content of α-cadinol. The highest nitrogen use efficiency was achieved under non-water stress conditions and the combined use of bio-fertilizer (Azotobacter and Azospirillum) and the use of 75% of the recommended amount of sulfur coated urea fertilizer. In the second year, the lack of water stress and the combined use of bio-fertilizer (Azotobacter and Azospirillum) and the recommended amount of sulfur coated urea fertilizer also resulted in a significant reduction in nitrogen use efficiency. In the first and second years, the lack of water stress and the combined use of Azotobacter and Azospirillum and the recommended amount of sulfur coated urea fertilizer resulted in increased flower yield and biological yield.

The response of corn single cross 640 to chemical fertilizers, biofertilizers and their interactions were studied. The experiment was conducted as a factorial arranged in completely randomized block design with three replications. Treatments consisted of combined application levels of urea fertilizer at five levels (0, 75, 150, 225 and 300kg pure nitrogen per hectare as urea fertilizer) and two levels of biological fertilizer (inoculated and non-inoculated). The results showed that the interaction of biofertilizer with urea fertilizer had significant effect on traits such as grain yield, number of grains per ear and thousand grain weight and plant height. The highest grain yield (10425.14 kg.ha-1) was obtained with 300 kg urea and inoculated with biological fertilizer and the lowest (5712.49 kg.ha-1) grain yield obtained in control level (no urea fertilizer) and non-inoculated with biological fertilizer. There is no difference between biological fertilizer with 225 kg of urea and biological fertilizer plus 300 kg of urea related to grain yield. It seems that the combination of chemical fertilizers with organic fertilizers can produce maximum yield that due to provide nutrients for plants.

In order to investigate the effect of manure, urea fertilizers and inculcation with Azotobacter chrooccum on yield and yield components of wheat Zagros cultivar, this experiment was conducted based on split-split plots with three replications in Ilam and in 2014-15. The experimental treatments including cow manure at two levels (non application and application 20 kilogram per meter square) as main plots, four levels of urea fertilizer (zero, 33, 66 and 100 percent of recommended urea chemical fertilizer) as sub-plots and Azotobacter chrooccum fertilizer at two levels (without inculcation and inculcation with Azotobacter) were assigned as sub-sub plots. The experiments results indicated that application of manure, urea fertilizer and Azotobacter chrooccum had a significant effect on yield, yield components and wheat biological yield. Manure triple interaction in urea fertilizer in Azotobacter chrooccum was significant on number of spike in square meter, number of grain in spike, one-thousand grain weight, grain yield, biological yield and harvest index at one and five percent probability levels, so that the highest number of spike per square meter (363 spikes), grain yield (4133/3 kilogram per hectare) and biological yield (8708.3 kilogram per hectare) in manure using treatment, using 60 percent recommended urea fertilizer and inculcation with Azotobacter and the lowest spike number in square meter (228.3 spikes), grain yield (2500.3 kilogram per hectare) and biological yield (5711 kilogram per hectare) were obtained in application, non-application of manure treatment, non-application of urea fertilizer and non-inoculation with Azotobacter. Thus, by using manure and 66 percent recommended urea fertilizer and also in addition to Azotobacter it can be possible to save the application of the fertilizer and to achieve the desirable yield in wheat.

This experiment was carried out to investigate the effect of biopolymer coated urea under deficit irrigation on ear yield, nitrogen uptake, nitrogen recovery efficiency and nitrogen use efficiency, grain protein and plant nitrogen content in sweet corn (KSc 403). The experiment was carried out in strip plot arrangement based on randomized complete block design with four replications in Agricultural Sciences and Natural Resources University of Khuzestan, Iran in 2015. The experimental treatments included; three levels of irrigation (100%, 80%, and 60% of plant water requirement) assigned to vertical plots and six levels of urea fertilizer (uncoated urea, sulfur-coated urea, starch-coated urea, agar-coated urea, and chitin-coated urea) randomized in horizontal plots. The results revealed that coated urea fertilizer with chitin could increase ear yield and NUE by of 20.2% and 32.9%, respectively, in comparison with uncoated urea fertilizer. The highest water productivity and economic water productivity was obtained from chitin coated urea and highest native soil nitrogen from non-coated urea fertilizer. The highest N uptakes and recovery efficiency were obtained in chitin-coated urea fertilizer and 100% of water requirement treatments. However, no significant difference was observed between this treatment and agar coated urea in 100% of water requirement. Redudcing 40% in water requirement decreased ear yield and NUE by 40.3% and 41.1%, respectively. The highest ear yield of sweet corn were obtained from 100% of water requirement (10238 kg.ha-1) and chitin coated urea fertilizer (9853 kg.ha-1) that was not significantly different with other biopolymer coated urea treatments. In conclusion, the results of this experiment showed urea coated fertilizer with biopolymers increased ear yield and nitrogen uptake in sweet corn and enhanced agronomic nitrogen use efficiency, nitrogen recovery and water productivity.

This study was designed and conducted in order to investigate the effect of different levels of urea fertilizer and brown seaweed extract (Nizamuddinia zanardinii) on the physiological traits and grain yield of wheat. Experiment was carried out in the form of factorial in completely randomized design with three replications at five levels of brown seaweed extract (zero, 5, 10, 15 and 20 percent) and three levels zero, 25 and 50 percent of recommended using rate of 46 percent urea fertilizer (the recommended using rate of urea fertilizer was 300 kilogram per hectare). After the growth and complete ripeness of wheat, the amount of grain soluble carbohydrate, the average weight of spike, the average number grains of spike, grains weight of spike, harvest index of spike, grain yield and biomass were measured. The obtained results showed, using seaweed extract led to a significant increase in the amount of investigated growth indices in comparison to control. In treatments in which the combination of seaweed fertilizer with 25 percent recommended using rate of urea fertilizer was used, the mentioned growth indices significantly increased, which indicated the synergistic and interaction of seaweeds and urea fertilizer. In treatments in which the mixture of seaweed extract has been used along with 50 percent of recommended using rate of urea fertilizer, the investigated growth indices showed significant decrease in comparison to the mixture of seaweed extract treatments along with 25 percent recommended rate of urea fertilizer.

This study was carried out to assess the effect of coated urea fertilizer on yield and yield components of sweet corn (KSC 403) under different irrigation regimes, in Ramin Agriculture and Natural Sciences University, Iran by using strip split plot in a randomized complete block design with four replications. Three levels of deficit irrigation (100%, 80 and 60% of calculated water requirement of sweet corn) were assigned as vertical factor and six sources of urea fertilizer (without urea, un-coated urea, sulfur-coated urea fertilizer, starch-coated urea, agar-coated urea and chitin-coated urea) were assigned to horizontal factor. Effects of deficit water and source of fertilizer were statistically significant on plant height, 1000 kernel weight, ear diameter, and number of rows per ear, ear yield, biological yield and harvest index. Maximum of plant height (153.23 cm), 1000 kernel weight (104.51 g), grain yield (9853.3 kg/ha) and biological yield (12471.6 kg/ha) were obtained in chitin coated urea fertilizer. Maximum of ear diameter (4.67 cm) and number of row per ear (13.22) were achieved in agar coated urea fertilizer and that of harvest index (45.79%) was indicated by starch-coated urea. Maximum of length of ear, number of kernels per row and grain yield were 23.65cm, 25.83 and 7142 kg/ha, respectively, and were obtained with the using of chitin-coated urea fertilizer and 100% water requirement. Minimum values of these traits were 13.54 cm, 5.56 and 871 kg/ha, respectively, and were obtained by using of control (no urea application) and 60% water requirement. Results showed that biopolymer coated urea is potent to improve some morphological characteristics and increase grain yield of sweet corn.

In order to investigate the effect of forage maize biochar and urea fertilizer application on bell pepper cultivar, a factorial experiment in a completely randomized design with three replicates and nine treatment was conducted. The treatments consisted of three levels of forage maize biochar (zero, 2, and 5% Soil weight) and three required urea fertilizer (75% 100%, and 120%). One bell pepper was transferred in 4-leaf pots containing 5 kg of soil and biochar, then in three stages and in each stage, 236, 314, and 376 mg kg-1 N of urea fertilizer was added to the pot. At the end stage of cultivation, EC, pH, Na, K, Ca+ mg, carbon organic, total nitrogen and wet yield fruit bell pepper measurements were done. The results indicated that the treatment of 120% urea fertilizer and 5 percentage biochar EC, pH, sodium, and total nitrogen cumulative in soil 41.7, 12.5, 2.1 and 58.3% and soil organic carbon 4.16 times, were compared to the control treatment. respectively. In 120% urea fertilizer and 5 percentage biochar treatment soil potassium increase by 96.8% in comparison with the control treatment. Also, the highest increase calcium and magnesium the treatment 100% urea fertilizer and 2 percentage biochar cumulative in soil by 58.3%. In addition, the results indicate that the treatment of 120% urea fertilizer without biochar increased the wet yield fruit of bell pepper by 61.5% compared to the control treatment.