To investigate the effect of vermicompost, N fertilizer and their integration on growth, biological and essential yields oil and its components in two populations (Varamin and Isfahan), an experiment was conducted in a randomized complete block design with three replications in the field of Isfahan Medicinal Plants Research Center in 2016. Fertilizer treatments including 100% urea, vermicompost 33.3 and urea 66.6%, vermicompost 66.6 and urea 33.3%, 100% vermicompost and control treatment (without fertilizer) as the first factor and Varamin and Isfahan populations as the second factor were selected. The results showed that the interaction effects of NITROGEN fertilizer and populations on all studied traits were significant. In both populations, NITROGEN fertilizer improved height, biological and essential oil yields, content of essential oil compounds (d-Carvone and its yield, α-phellandrene and linalool; except p-Cymene and Limonene in Isfahan population). Since in medicinal plants, the quantity (biological yield) and quality (essential oil and d-Carvone; the most important ingredient and the highest amount of essential oil in this experiment), 66.6% vermicompost + 33.3% urea in Varamin population, was the best treatment in the experiment. In addition an in the direction of human health and sustainable agriculture, it is possible to reduce 33% of chemical fertilizers application and pollution; however, in terms of other essential oil contents (α-phellandrene, Linalool and p-Cymene), 100% vermicompost fertilizer treatment was superior in Isfahan population.

Introduction Annually around 2 million tons of NITROGENous fertilizers is used in Iran. It was reported that increasing trend of chemical fertilizers application over the last 30 years with some fluctuations. So, proper fertilizer management in Iran has great effect on soil and water quality. Salinity stress is known as a worldwide abiotic stress responsible for reduced crop production. It is estimated that annual losses of yield due to salt induced land degradation is US$ 27. 3 billion globally. Social and economic dimensions of salinity stress can be employment losses as well as environmental degradation. In addition, it is well documented that application of chemical fertilizers usually improve plant performance under saline conditions but results in plant fertilizer requirement under salt affected soils are contrary. While there is little evidence of yield benefits due to application of fertilizers in salinized fields at rates beyond optimal in non-saline conditions, there is enough evidence indicating that soil salinity does not affect or decrease plant fertilizer needs. It is well documented that salinity stress negatively affects wheat growth rate and it postpone the ripening in wheat plants. While flowering happened at 59. 33 days after planting at non-saline conditions, it occurred 62. 22 days after planting for salt affected plants. The negative effect of salinity on wheat NITROGEN content is reported. This is due to the negative effect of salinity stress on root growth and the chloride on NITROGEN uptake. A hypothesis that salinity stress can adversely affect NITROGEN uptake pattern of wheat has been proposed, but, contradictory results have been reported. Thus NITROGEN fertilizer management may need to be modified under arid and semiarid conditions of Yazd province with wide range of irrigation water qualities. Accordingly, the objectives of this field study were to elucidate the effect of salinity stress on NITROGEN uptake pattern and NITROGEN timing in wheat. Materials and methods A field experiment was conducted on wheat at Sadooq Salinity Research Station, Ashkezar, Yazd, Iran. Mean annual temperature is 18° C and precipitation is 70 mm. The treatments, NITROGEN fertilizer sources (ammonium sulphate and urea) and three irrigation water qualities (1. 7, 7. 22 and 12 dS m-1), arranged in a randomized block, split plot design with three replications. Consisting 20 rows of wheat, each field plot was 6*4 m. All plots received common agricultural practices including tillage and fertilizer application. Regarding typical recommendations and guidelines for this region and soil type, all fertilizers, except urea that applied in 2 splits, were soil-applied before planting. NITROGEN was applied at a rate of 105 kg ha-1 at two stages (90 and 120 days after planting). As soil phosphorous and potassium content was above threshold level, these elements were not applied for wheat production. Plant samples were provided at four growth stages including tillering, stem elongation, flowering and harvest. The samples were analyzed for NITROGEN content. Plant NITROGEN content was determined using kjldal method. The analysis of variance for different parameters was done following ANOVA technique. When F was significant at p ≤ 0. 05 level, treatment means were separated using DMRT. Results and discussion The soil at the experimental site was calcareous with 31. 5% total nutrient value, sandy loam texture, high pH (8. 06) and low organic carbon (0. 51 %). The results showed that wheat top yield depends on irrigation water salinity level as well as NITROGEN management. While a sigmoidal trend in wheat top yield for all treatments observed over time, increasing irrigation water salinity from 1. 7 to 7. 22 and 12 dS m-1 decreased wheat yield at harvest from 11058 to 7183 and 7933 kg ha-1. In other words, salinity stress significantly decreased wheat performance by 35. 04 and 28. 26 percent. The results also showed that NITROGEN content decreased over time. While NITROGEN content was more than 5 percent at tillering it decreased to 1 percent at harvest. NITROGEN uptake was not affected by NITROGEN source but it was affected negatively by irrigation water salinity. Depending on salinity levels and the application rate of NITROGEN, NITROGEN uptake by wheat ranged from 81 to 189 kg ha-1. However, NITROGEN uptake was not affected significantly by NITROGEN sources. Conclusion Overall, it was concluded that salinity stress did not affect NITROGEN uptake pattern of wheat under field conditions of the experiment. As more than 80 percent of NITROGEN was uptaken from mid tillering onward, it is recommended that just only 15 percent of NITROGEN fertilizer be applied at planting. This would increase NITROGEN uptake efficiency and prevent soil, water and air pollution.

A field experiment was conducted to examine the effects of different depths of NITROGEN (N) fertiliser placements on N accumulation, remobilisation and NO3--N content in soil of rainfed wheat. NITROGEN was applied on the surface (D1) and in the 10 cm (D2), 20 cm (D3) and 30 cm (D4) soil layers from 2010 to 2012. Compared with D1 and D2, D3 and D4 treatments obtained significant higher N distribution amounts in grain and N accumulation amounts at maturity. D3 and D4 treatments increased the N accumulation amount of vegetative organs at anthesis and at maturity. D3 treatment resulted in significantly higher N translocation amounts from vegetative organs to grains compared with D1 and D2 treatments and had no significant difference with D4 treatment. Compared with the D1 and D2, D3 and D4 treatments obtained significant higher NO3--N contents in the 20 cm to 120 cm soil layer at anthesis from 2011 to 2012. However, D3 treatment showed no significant differences with D1 and D2 treatments at maturity in terms of the NO3--N contents in the 40 cm to 100 cm soil layer. D4 treatment produced the highest NO3--N contents in the 40 cm to 140 cm soil layer. Grain yield, N uptake efficiency, apparent N recovery efficiency, N agronomic efficiency and N partial factor productivity were significantly increased by D3 and D4 treatments. These results suggest that the D3 treatment facilitates the best wheat production and highest efficiency among all treatments.

One way to increase NITROGEN use efficiency of NITROGEN fertilizer to determine the right time is the rice, the most important tools like leaf chlorophyll color diagram Metro is done. This project was carried out tested split plot completely randomized block design with three replications at Rice Research Institute in Rasht. Main plots rice at three levels include: hybrid (Dilam 1), the Khazar and Hashemi and sub plots amounts of fertilizer NITROGEN in five levels, including: custom (Level Cody conventional fertilizer by farmers), 20, 30, 40 and 50 kg/ha NITROGEN after each reading and low numbers of leaf color diagram was too critical. Results of physiological traits also show that crop yield has 88/35 kg/ha by Khazar and 41/12 percent recycling efficiency ratio has been superior to other treatments. Finally, according to the results of agronomic and physiological traits can be used to khazar and hybrid varieties of each reading and low numbers obtained critical value for 30 kg/ha and 20 kg/ha Hashemi variety of NITROGEN fertilizer can be used.

The application of crop models to simulate crop responses to water and NITROGEN (N) is crucial for improving agricultural management. The majority of these models involve complex equations and require several input parameters for calibration. AquaCrop simulates crop response to different N levels using a semi-quantitative approach, which simulates the effect of N stress on transpiration and biomass production during the growing season. This model does not provide information on the optimal timing and quantity of N fertilizer application for efficient farm management. In the present study, a direct simulation approach based on the concept of a critical NITROGEN curve was applied to simulate the effect of N deficiency on transpiration and biomass production. The main objective of this study was to evaluate a direct simulation approach and compare its results with those derived from the semi-quantitative approach. For this purpose, experimental data were collected from two years of maize cultivation. Biomass and plant NITROGEN concentrations were measured during the growing season. The results showed that the RRMSE (relative root mean square error) index in biomass simulation by the direct method was, on average, 4% lower for each treatment compared to the semi-quantitative approach. In addition, increased N stress led to increased errors in simulating biomass. Thus, the RRMSE for biomass simulation using the direct method was 26.48 % and 30.96% for treatments under the highest stress, and 9.57% and 15.75 % for non-stressed treatments. In general, these findings show that integrating the critical NITROGEN concentration concept into crop models provides more accurate estimates for crops under NITROGEN stress.

Due to an increasing demand of leaf vegetables, and hence their economic importance in the tropics, it is very common that excessive fertilizer N rates are applied to vegetable gardens and fields to attain high yield. This calls for more information on their nutrient requirements. In this study, we designed experiments to explore the effect of organic N levels on the yield and agronomic N use efficiency (ANE) by chinese cabbage (Brassica rapa) and amaranthus (Amaranthus cruentus). The experimental design was a randomized complete block design consisting of chinese cabbage (CC) and amaranthus (AM) with three replicates. Chicken manure (CHM) and cattle manure (CAM) were the source of N. The treatments were 0, 200, 300 kg N ha-1 and 0, 170, 250 kg N ha-1 for CC and AM, respectively. Chicken manure resulted in increased fresh and dry matter yield of CC and AM compared to CAM. All treatments at first harvest induced higher marketable yield of vegetables than controls except with low levels of CAM N. At second harvest, only 300 kg CHM N ha-1 resulted in significantly (P<0.05) higher marketable yield of CC compared to control, while no significant difference observed in AM by 170 kg CAM N ha-1. Agronomic N use efficiency was decreasing with increasing N levels. NITROGEN levels can be reduced to 200 and 170 kg N ha-1 for CC and AM without significantly affecting the yield.