Drought Tension and nitrogen fertilizer are among the most important issues that researchers usually consider investigating the physiological yield and yield of new crops. The present research was conducted in the form of a statistical design of randomized complete blocks in the form of split plots with three irrigation levels in the main plots, including no drought tension or 60 percnt evaporation from Class A evaporation pan, medium tension or 90 percent evaporation from Class A evaporation pan and severe tension or 120 percent evaporation from Class A evaporation pan and six levels of nitrogen fertilizer including non-use of nitrogen fertilizer and values of 50, 75, 100, 125, 150 kilogram of nitrogen from urea source in subplot with three repetitions in Dare Shahr in 2019. The results of comparing the mean interaction of drought tension and nitrogen fertilizer treatments in grain nitrogen showed that in the absence of drought tension and application of 150 kilogram per hectare nitrogen fertilizer, the highest grain nitrogen was 3.53 percent and the lowest in severe drought tension and lack of nitrogen fertilizer application was 1.423 percent. Also, in all three levels of tension, the lowest and highest grain nitrogen was observed in non-consumption (control) and 150 kilogram nitrogen fertilizer, respectively. Comparison of the mean interaction of drought tension and nitrogen fertilizer treatments in grain yield showed that in the absence of drought tension and application of 150 kilogram per hectare nitrogen fertilizer, the highest grain yield was 2519.3 kilogram per hectare and the lowest was in severe drought tension and non-application of nitrogen fertilizer at the rate of 941.3 kilogram per hectare was obtained. Also, in all three levels of tension, the lowest and highest grain yield was observed in the non-consumption treatment (control) and 150 kilogram per hectare of nitrogen fertilizer, respectively. Due to the improvement of quinoa yield components by increasing the amount of nitrogen consumption and obtaining more grain yield, especially in water availability conditions, the results indicate high quinoa fertilizer.

In order to study the effect of different green manure crops and nitrogen sources on some growth characteristics of canola and weed biomass,a field experiment was conducted in experimental farm of Agricultural Faculty of ShahidChamran University of Ahvaz at 2013-2014 growing season. Experimental design was split plot on randomized complete block design (RCBD) with three replications. Main plot was different green manure crops including Millet, Barley, mungbean, intercropping of millet and mung bean and fallow (without green manure application) and subplot were different nitrogen sources at three levels includes (no nitrogen fertilizer(Control),50 % chemical nitrogen biological nitrogen fertilizer(Nitroxin) and 100 % chemical nitrogen). In order to assessment of canola leaf area index and weed biomass, three sampling date(50,100 and 150 days after sowing) were determined. The result showed that the highest grain yield (4467.2 kg/ha) was related to mungbean and 50 % chemical nitrogen biological nitrogen fertilizer (Nitroxin) and the lowest (1434.2 kg/ha) was obtained at no nitrogen fertilizer and green manure treatment (control).Also, the highest biological yield (10401/5kg/ha) was revealed at mungbean millet intercropping and 50 % chemical nitrogen biological nitrogen fertilizer (Nitroxin). The lowest biological yield(3875kg/ha) was obtained at control treatment. control treatment and the highest oil yield (1795/45 kg/ha) was obtained at 50 % chemical nitrogen biological nitrogen fertilizer (Nitroxin). The 50 % chemical nitrogen biological nitrogen fertilizer (Nitroxin) and the intercropping of millet and mung bean had the highestyield components. Also the results showed that the highest canola leaf area index(LAI) (4.51) was at 150 days after planting and 50 % chemical nitrogen biological nitrogen fertilizer (Nitroxin) and the lowest (0/03) was obtained at 150 days after planting and control treatments. The weed results showed that the highest weed biomass (150.33 gr/m2) was obtained at the first sampling date, fallow and no nitrogen application and the lowest(23.34 gr/m2) was related to the third sampling date, The 50 % chemical nitrogen biological nitrogen fertilizer (Nitroxin) and the intercropping of millet and mung bean. The results of this research showed that the green manure plants with chemical and biological fertilizers caused to canola growth improvement and decreased the weed biomass.Totally the results of this research showed that application of green manure in combination with biological fertilizer and chemical fertilizer could be reduced the chemical fertilizer and also improvement of canola growth , increased in leaf Area Index. it concluded that decreased the weed dry weight.

Effect of nitrogen fertilizer and plant density on root yield, quality and physiological traits of sugar beet (cv. Pars) under tape-drip irrigation condition was assessed in strip factorial plot arrangement using randomized complete block design with four replications. Two levels of planting patterns (40-60 cm and 40-50 cm) and four levels of nitrogen fertilizer; zero (N0), 50% (N1), 75% (N2) and 100% (N3) of the recommended levles for furrow irrigation) were assigned to vertical plots and two levels of row spacing (14 and 20 cm) randomized in horizontal plots. The experiment was carried out in two succeive sugar beet growing seasons (2013 and 2014) in the research field station of of Sugar Beet Research Institute, Karaj, Iran. Nitrogen fertilizer had significant effect on root and sugar yields. Decreasing nitrogen fertilizer to 75% of recommendation didn’t significantly influence root and sugar yields. The least and highest nitrogen accumulation of 99.9 and 240.3 kg.ha-1 were measured at zero and 100% levels of recommended nitrogen fertilizer, respectively. Accumulated nitrogen was partitioned greater in roots (58%) than shoots (42%). The highest Nitrogen Use Efficiency (NUE) for producing sugar was 50.8 (50.8 kg of sugar.kg-1 of nitrogen) in the treatment without nitrogen fertilizer application which was 21.7, 24.8 and 31.3 percent higher than treatments with 50%, 75% and 100% of recommended nitrogen fertilizer, respectively. Radiation penetration under the canopy showed that more radiation was intercepted in denser plant population and higher nitrogen fertilizer applications. Nitrogen fertilizer had significant effect on physiological traits such as SPAD value, chlorophyll content, maximum photochemical efficiency of photosystem II (Fv/Fm) and number of leaves. It was concluded that tape-drip irrigation system could reduce 25% of nitrogen fertilizer application without significant changes in important qualitative, quantitative and physiological traits of sugar beet.

This study was conducted to investigate the effect of Potassium Thiosulfate and Nitrate fertilizers on yield, water use efficiency and control of tuber cracking of potato cultivars. This research was conducted Factorial based on randomized complete block design with three replications at the National Potato Research Station located in Ardabil during 2021. The first factor includes Potassium Thiosulfate at three levels (zero, 10 and 20 liters per hectare with irrigation water), the second factor contains Ammonium Nitrate at three levels (based on soil test, 30% and 60% more than soil test) and third factor included four potato cultivars (Agria, Savalan, Anusha and Takta). The results showed that there was a significant difference between the levels of Potassium Thiosulfate fertilizer, cultivars, interaction effect of Potassium Thiosulfate fertilizer and Nitrogen fertilizer and tripartite interaction of Potassium Thiosulfate fertilizer, Nitrogen fertilizer and cultivars in terms of tuber yield, tuber number and weight per plant, plant height, main stem number per plant, water use efficiency, mean of number, length, width, depth and surface of tuber cracking. The highest tuber yield, tuber weight per plant and water use efficiency in the treatment of Potassium Thiosulfate fertilizer 10 liters per hectare and Nitrogen 250 and 328 kg.ha-1 in Takta cultivar, Potassium Thiosulfate fertilizer 10 liters per hectare and Nitrogen fertilizer 400 kg.ha-1 in Savalan cultivar and 20 liters per hectare of Potassium Thiosulfate fertilizer and 328 kg.ha-1 of nitrogen were observed in Savalan cultivar. Based on the results of factor analysis, in the treatment of zero liters per hectare of Potassium Thiosulfate fertilizer and 328 kg.ha-1 of Nitrogen fertilizer of Takta and Savalan cultivars; in the treatment of 10 liters per hectare of Potassium Thiosulfate fertilizer and 250 kg.ha-1of Nitrogen fertilizer in Takta and Agria cultivars, 328 kg.ha-1of Nitrogen fertilizer in Takta cultivar and 400 kg.ha-1 Nitrogen fertilizer in Anusha, Takta and Savalan cultivars and 20 Potassium Thiosulfate fertilizer per hectare and 250 kg.ha-1 Nitrogen fertilizer in Takta cultivar and 328 kg.ha-1 Nitrogen fertilizer in Savalan cultivar had the highest values in terms of tuber yield, tuber number and weight per plant, plant height and water use efficiency. Based on the results of cluster analysis, the fourth group includes treatments of 10 liters per hectare of Potassium Thiosulfate fertilizer and 250 and 328 kg.ha-1 of Nitrogen fertilizer in Takta cultivar and 400 kg.ha-1 of Nitrogen fertilizer in Savalan cultivar and 20 liters per hectare of Potassium Thiosulfate fertilizer in 328 kg.ha-1 of Nitrogen fertilizer in cultivar was in Savalan cultivar and in terms of tuber yield, tuber number and weight per plant, plant height, water use efficiency had the highest amount and without the number of tubers with crack in the plant.

In order to investigate the effects of nitrogen fertilizer levels on THE yield and quality of potato, (Solanum tuberosum L.) a field experiment was conducted based on randomized complete blocks design with 3 replications in the Research Field of the College of Agriculture, Ferdowsi University of Mashhad. Nitrogen topdress fertilizer was applied in two levels of 100 and 150 kgN.ha-1 and in two nitrogen indexes of 90 and 95 percent. In this research, chlorophyll meter was used to identify the required proper time of potato crop to nitrogen fertilizer. The results indicated that 95 percent OF nitrogen index versus 90 percent OF nitrogen index has a better efficiency in THE AUGMENTATION of potato crop yield. But in 95 percent index, nitrogen fertilizer levels of 100 and 150 kgN.ha-1 did not SHOW significant difference in tuber yield. Nitrogen indexes and nitrogen fertilizer levels did not have A significant effect on the tuber dry matter percent. 95 percent nitrogen index and nitrogen fertilizer levels caused A significant DECREASE on the tuber specific gravity. 90 percent nitrogen index and nitrogen fertilizer level of 100 kgN.ha-1 caused A significant DECREASE on the tuber of protein. The percentage of medium and large tuber increased when the nitrogen fertilizer was increased. In general it seems that THE nitrogen fertilizer application, in addition to producing desirable yield of tuber, leads to make desirable quality of tuber and economy in nitrogen fertilizers application by using chlorophyll meter.

To study the effects of plant growth promoting rhizohacteria on yield and yield components of four chickpea (Cicer arietinum L.) cultivars in Ilam region under rainfed conditions, a field experiment was conducted using factorial arrangement based on randomized complete block design with three replications at the Agricultural Research Center of Ilam during 2014-2015 cropping seasons. Cultivars under study were Azad, Hashem, Arman and an ecotype. Treatments were plant growth promoting rhizohacteria (without inoculation, 10 kg nitrogen fertilizer, 20 kg nitrogen fertilizer, Azospirillum brasilense숫憢 nitrogen fertilizer, Azospirillum brasilense kg nitrogen fertilizer, Azospirillum brasilense kg nitrogen fertilizer, Azotobacter chrococcum, without nitrogen fertilizer, Azotobacter chrococcum kg nitrogen fertilizer, Azotobacter chrococcum kg nitrogen fertilizer. The interaction effect of cultivar×plant growth promoting rhizohacteria (PGPR) were significant on pods per plant, seed per pod, 100-seed weight, seed yield, biological yield, plant height and protein content; Thus, application of chemical fertilizer and PGPR in these cultivars increased all traits under study. The highest mean seed yield of 1533 kg.ha-1 was obtained from interaction effect of Azad cultivars×Azospirillum kg nitrogen fertilizer and lowest grain yield with mean yield of 529 kg.ha-1 observed from interaction effect of ecotype×without inoculation that increased 65.5% to check treatment. Inoculation with Azesperilluim was found to be more effective in Azad and Hashem cultivars and inoculation with Azotobacter was found to be more effective in Arman cultivar and ecotype. According to the results obtained from this study, Azad cultivar and inoculation with Azospirillum kg nitrogen fertilizer produced highest sedd yield under rainfed condition of Ilam Agricultural Research Center.

Inclusion of cover crops in crop rotations has several benefits such as supplying nitrogen for the next crop. To investigate the effect of cover crops and different levels of nitrogen fertilizer on tuber yield, yield components, and different nitrogen efficiency indices of potato, a filed experiment was conducted as split plots arrangements in randomized complete block design with three replications in 2018-19 and 2019-20 growing seasons at the agricultural research farm of Faculty of Agriculture and Natural Resources, Razi University, Kermanshah, Iran. The main plots was assigned to cover crop at four levels including; rye, vetch, mixed (vetch + rye) and control (no cover crop) and the sub-plots was nitrogen fertilizer application at four levels including; 0 (control), 33, 66, and 100 percent of the recommended fertilizer level based on the soil test. The results showed that treatments had significant effects on tuber yield and yield components, plant height, the number of main stem per plant, nitrogen use indices and tuber nitrate content. Vetch and mixed treatments along with application of 66 percent of nitrogen fertilizer led to the 13 and 8 percent increases in potato yield when compared with application of 100 percent of nitrogen fertilizer without cover crop, respectively. Maximum tuber yield obtained in vetch with application of 66 percent of nitrogen fertilizer (35.42 ton.ha-1) and the least tuber nitrate (31.92 mg.kg-1) wasmeasured in control (without nitrogen fertilizer). Application of nitrogen fertilizer had a significant negative effect on nitrogen use efficiency as the highest nitrogen use efficiency (94.78 kg.kg-1) was obtained by inclusion of vetch as cover crop and without application of nitrogen fertilizer. In conclusion, our findings showed the positive effect of cover crops along with application of optimum level of nitrogen fertilizer on tuber yield potato, plant height and number of main stem per plant. This can be considered as a crop management package that leads to the reduction of application of chemical fertilizers, prevents its adverse effects on environment and more economic benefits for farmers.

In order to study the effects of nitrogen fertilizer rates and plant number on yield and yield components of two rice cultivars, a field experiment was carried out in Babol city- during 2010. A split-split plot experiment on the basis of randomized complete block design with 3 replications and 3 factors including fertilizer rate (0, 57.5 and 115 kg.ha-1), plant number per hill (3, 4 and 5) as sub plot and cultivars (Fajr and shiroudi) as sub sub plot were used. Results showed the rates of nitrogen fertilizer had significant effect on grain yield, harvest index, fertile tillers number, panicle number and biological yield. Also, different levels of plant number have not significant effects except of panicle number, grain yield and biological yield. With increasing nitrogen fertilizer application, grain yield was increased significantly compared with control treatment (without nitrogen fertilizer application). Interaction effect between nitrogen fertilizer rate and cultivar was significant at 1% probability levels for grain yield and panicle number in which the highest yield was belong to the nitrogen fertilizer rate of 115 kg.ha-1 and Shiroudi cultivar. Among the mentioned traits, fertile tillers number, panicle number and biological yield had the highest correlation with grain yield.

To study of combined effect of vermicompost and nitrogen fertilizers, nitroxin on yield and yield components of potato a factorial based on randomized complete block design (RCBD) with three replications was conducted in Damavand city in 2015. The first factor was three levels of vermicompost including no application (control), application 5 and 10 ton.ha-1 and the second factor was four levels of nitrogen fertilizers and Nitroxin including no application(control),application 100% of the recommended consumption nitrogen fertilizers(150kg.ha-1urea),application nitrogen bio fertilizer (5kg.ha-1Nitroxin)and application 75% of the recommended consumption nitrogen fertilizers(100kg.ha-1urea) and nitrogen bio fertilizer (5kg.ha-1Nitroxin). Analysis of variance showed that vermicompost and integration of nitrogenous fertilizer and Nitroxin in most traits were significant. Results of mean comparison showed that the highest tuber yield of five tons per hectare use of vermicompost (22/52 kg.ha-1) and taking seventy-five percent of the recommended amount of nitrogenous fertilizer with biological Nitroxin (23/8 kg.ha-1). Finally the consumption of 5 tons per hectare use of vermicompost and application 75% of the recommended consumption nitrogen fertilizers (100kg.ha-1urea) and nitrogen bio fertilizer (5kg.ha-1Nitroxin) the results were the best

To evaluate response of two rice cultivars to different rate of nitrogen fertilizer, an field experiment was carried-out with three factors including cultivar at two levels (Gilaneh and Abjiboji), nitrogen fertilizer application at two levels (split and non-split) and rate of nitrogen fertilizern at five levels (0, 60, 75, 90 and 105 kg.ha-1 nitrogen from urea source). These factors were arranged as factorial in randomized complete block design with three replications at the experimental field of rice research institute (Rasht) and rice research station of Chaparsar (Tonkabon) in two growing years 2014 and 2015. Grain yield, plant height, harvest index and agronomic nitrogen use efficiency were measured. The results revealed that the difference between Gilaneh and Abjiboji (A local cultivar) for grain yield and plant height was the same in two growing seasons. However, the grain yield of Gilaneh was significantly higher than Abjiboji, and its plant height was significantly shorter than this local rice cultivar at all levels of fertilizer in two growing seasons. Also, the response of graing yield of these two rice cultivars to nitrogen fertilizer was different in two locations (Rasht and Chaparsar). Therefore, management of nitrogen fertilizer application should be different in Rasht and Chaparsar. The superiority of nitrogen use efficiency of Gilaneh in split application of nitrogen fertilizer (Max. 18.5 kg.kg-1) compare to Abjiboji (12 kg.kg-1), revealed the superiority of Gilaneh and split application of nitrogen fertilizer. For Abjiboji split application of 75 kg.ha-1 nitrogen fertilizer (with grain yield of 3830 kg.ha-1) can be recommended in Chaparsar, and 90 kg.ha-1 nitrogen fertilizer as nonsplit in Rasht (with grain yield of 4050 kg.ha-1) were suitable. However, for Gilaneh, new improved rice cultivar, split application of 90 and 90-105 kg.ha-1 nitrogen fertilizer can be recommended in Chaparsar and Rasht (with grain yield of 5050 and 4650 kg.ha-1), respectively were more suitable.