Cotton is a plant that responds to the amount of irrigation water and irrigation time, and due to lack of water in Golestan province, the need for optimal use of water unit is more than ever before. This will not be achieved except through modern methods of surface irrigation or irrigation under pressure and appropriate management of irrigation and increasing water use efficiency.

This experiment was conducted as a split plot design in a factorial design with three replications at Hashem Abad Cotton Research Station. Physical and chemical parameters of soil such as soil texture, bulk density, moisture content of crop capacity and wilting point, soil salinity and soil acidity before cultivation were measured by sampling from two depths of 0.25 to 25 cm and 25 to 50 cm. Farm fertilizer requirement was calculated according to the results of the experiments. The distance of cotton cultivation during the studied surface was considered the same. Before irrigation was done due to soil moisture content. Planting two cotton cultivars was done randomly. During the growing season and before the first irrigation, a single-hinged rainwater system was implemented. During irrigation period, irrigation was carried out based on the water requirement of Plot i5 and irrigation continued on the basis of the water requirement of this plot to reach the farm capacity. During the growth period, the symptoms and the indicators of yield components included plant growth measurements, first flowering time, time of the first product, etc., and finally the yield was recorded. Different amounts of irrigation water treatments including rain irrigation, irrigation over water requirement as main plots and treatments of different amounts of nitrogen fertilizer including 0, 33, 66 and 100 percent fertilizer recommendation as well as cotton cultivars were considered as subplots.

The results showed that the highest yield (4362 kg / ha) was related to 4I treatment and the lowest yield was obtained from rain fed (without irrigation) with 3379 kg / ha. The yield of I2, I3, I4, I5 and I6 treatments was 2,2, 16,7, 29,1, 8,1 and 15/7 percent, respectively, than rain fed (I1). Among fertilizer treatments, the highest yield was related to unfermented fertilizer application, which was significantly different with treatments of 66% and 100% fertilizer requirement. The lowest yield was 66% fertilizer requirement. In a research year (2012) due to suitable rainfall in the growing season, cotton plants were well-grown, and any excess water or nitrogen fertilizer accelerated vegetative growth which ultimately led to a decrease in reproductive growth and Subsequently, performance declined. In terms of precocious percentage, rain and I4 treatments were the earliest and the shortest treatments. Different amounts of nitrogen fertilizer had no effect on premature percentage. The highest number of bolls per plant was related to I5 and I6 treatments, which difference was significant with I1 and I2 treatments, but not significant with I3 and I4 treatments. The amount of nitrogen fertilizer application from 0% to 100% of fertilizer requirement did not have a significant effect on the number of bolls per plant.

The yield of Golestan cultivar was 17.9% higher than that of B-557. Water use efficiency in rainfed and irrigation treatments was 1.51 and 0.81 kg / m 3 / ha, respectively. B was 557 earlier than Golestan cultivar. Two cotton cultivars called Golestan and 557 B were identical in number of bolls per plant. It is recommended to select Golestan cultivar as a basic cultivar pattern. In rainfed overwrought years, an irrigation can be done or watering is done in supplementary form.

In order to study response of yield and some physiological traits of sweet basil under nitrogen fertilizers (biological, chemical and integrated) in additive intercropping a field experiment was carried out in the Experimental Farm Faculty of Agriculture, Lorestan University during 2014-2015 growing seasons. The treatments were arranged in a factorial split-plot-in time experiment based on Randomized Complete Blocks Design with three replications. Experimental treatments were 100% chemical fertilizer (N), bio-fertilizer (nitroxin), integration of bio-fertilizer + 50% chemical fertilizer and control, different intercropping systems consisted of sole cropping sweet basil and the additive intercropping of corn + 25% sweet basil, corn + 50% sweet basil, corn + 75% sweet basil and corn + 100% sweet basil and three harvest. The results belong to sweet basil showed that integration of bio-fertilizer + 50% chemical fertilizer had the highest fresh yield (7579.25 kg ha-1), dyr yield (1303.83 kg ha-1), plant height (50.62 cm), chlorophyll a (0.51 mg g-1 FW), chlorophyll b (0.36 mg g-1 FW) and total chlorophyll (0.87 mg g-1 FW). However, integration of bio-fertilizer + 50% chemical fertilizer in terms of mentioned traits except for plant height had no significant difference with 100% chemical fertilizer treatment. Among different intercropping systems, sole cropping pattern in terms of all traits evaluated in this study had the highest amounts. The highest LER (1.566) belonged to corn + 100% sweet basil with bio-fertilizer.

Sweet basil (Ocimum basilicum L.) is one of the most important medicinal plants that its essential oil used in different medicinal industries. In this research, effects of different types of fertilizers were evaluated on quantitative and qualitative characteristics of basil. The research was conducted under field condition in complete randomized block design with three replications. The treatments included vermicompost, livestock manure chemical fertilizer, biofertilizer (Azospirillum/ Azotobacter), combinations of vermicompost and 50% chemical fertilizer, combinations of biofertilizers and 50% chemical fertilizer, manure and control. The highest dry yield in first and second harvest observed in combinations of biofertilizer and 50% chemical fertilizer. Results showed highest essential oil content obtained in chemical fertilizer and combinations of biofertilizer and 50% chemical fertilizer. According to the results, application of chemical fertilizer, biofertilizer and combinations of biofertilizer and 50% chemical fertilizer increased essential oil yield to 41%, 33% and 38%, respectively. Identification of essential oil components showed that content of Eugenol and Methyl chavicol increased with application of nitrogen fertilizers. It is concluded that application of biofertilizers enhanced quantitative and qualitative characteristics in this plant. Generally, it seems that using of biofertilizers could improve basil performance in addition to reduction of environmental pollution.

In order to evaluate the effect of inorganic nitrogen on dry matter and nitrogen remobilization in spring barley under water deficit conditions, a factorial experiment based on completely randomized design with three replications was conducted in the greenhouse condition in 2012. Irrigation schedules imposed in pots at three levels (35%, 60% and 85% field capacity) and the nitrogen fertilizer applied at three rates (40, 80 and 120 kg ha-1) on the EBYTW-11 spring barley genotype. The results showed that the DM remobilization from different parts of plant (stem, flag leaf, other leaves and peduncle) to the grain was affected by water deficit and nitrogen levels, so that the highest amount of dry matter remobilization belonged to other leaves under mild water stress (FC 60%) with 40 kg ha-1 nitrogen. Also, the efficiency of dry matter transferring from the foliar to the grain was influenced by nitrogen application and water deficit. The contribution of DM remobilization from stem and peduncle was significantly affected by water deficit and nitrogen. The maximum efficiency of dry matter allocation to grain belonged to the flag leaf under severe stress with 40 kg ha-1 nitrogen. It seems that under severe stress, the most amount of dry matter is transmitted to the spikes because of earliness, accelerated aging and loss of lower leaves. The results showed that when the plant is exposed to nitrogen deficiency in the soil, nitrogen remobilization efficiency from vegetative organs would be higher.

Understanding of wheat root system is important in dryland conditions. Root development، important factor in wheat production under water limiting conditions، can be affected by environmental factors especially nitrogen fertilizer. A field experiment was carried out to study the nitrogen rates and application times on root morphology of three rainfed wheat genotypes، using a split-splitplot based on a randomized complete block design (RCBD) with 3 replications in Maragheh Dryland Agricultural Research Institute (DARI) during 2010-2011. Treatments were two nitrogen application times (all in fall، and two-third in fall + one-third in spring) assigned in main plot; four nitrogen rates (0، 30، 60 and 90 kg/ha) assigned in sub-plots; and three wheat genotypes (Azar2، Cereal-3 and Cereal-4) assigned in sub-subplots. Root samples were collected at stem elongation stage (GS22) to study root characteristics. The results showed that nitrogen applications resulted in significantly increasing plant height، crown root number، shoot fresh weight، root fresh weight، root dry weight، above-ground plant biomass، total root volume، ratio of root volume per soil volume compared with control (no nitrogen). The increasing trends in all parameters were found linearly upward to the last level of nitrogen treatment used. Nitrogen application in fall significantly increased crown root length (P<0. 05) by 11 percent compared to split application. Also، nitrogen fall application significantly affected crown root and coleoptile lengths of genotypes. Cereal-4 genotype had better root morphological characteristics compared to other two genotypes. Nitrogen fertilization could affect rainfed wheat root characteristics in order to produce desirable traits. In general، it was concluded that fall application of 60 kg N/ha could increase rainfed wheat grain yield due to improvement of root systems.

Nitrogen is one of the most limiting nutrients for cereal production in many parts of Iran. The effects of crop residue incorporation [0 (control), 25 and 50% of wheat (Triticum aestivum L.)] and nitrogen (N) levels (0, 150, and 300 kg ha-1) on corn (Zea mays L.) grain yield and nitrogen use efficiency were investigated at Agricultural Research Station, Shiraz University, Shiraz, Iran for two years (2009-2010). The experiments were carried out as a split plot based on randomized complete blocks design with three replications. The results showed that with increasing nitrogen fertilizer (from 150 to 300 kg ha-1) and crop residues (from 25 to 50%), RNE (Recovery N Efficiency) and ANE (Agronomic N Efficiency) were reduced. Application of nitrogen more than 150 kg ha-1 increased the amount of nitrogen loss from 69 to 121 kg ha-1. There was a liner relationship between the amounts of nitrogen higher than 150 kg ha-1, and the NHI (Nitrogen Harvest Index), but adding more than 50 percent of crop residues caused no significant difference in the NHI. The maximum grain yield was obtained in plants treated with 300 kg N ha-1 and 25 percent of crop residues incorporation. According to results, the use of 25% of crop residue and 150 kg N ha-1 due to acceptable yield, reduce nitrogen loss and increase the efficiency of nitrogen better than other treatments.

To investigate the effect of biopolymer coated urea fertilizer on physiological traits related to yield of sweet corn under deficit irrigation, an experiment was carried out in strip split plot based on randomized complete block design with four replications in Agriculture and Natural Resources Science University of Khuzestan, Iran, in 2016. Irrigationin three levels (100, 80 and 60% water requirement) in length of blocks and urea fertilizer in six levels (without fertilizer as check treatment, pure urea, sulfur-coated urea, starch-coated urea, agar-coated urea and chitin-coated urea) in vertical strips to irrigation in each block were used. The results showed that the effect of irrigation and type of coated nitrogen fertilizer on leaf relative humidity, chlorophyll-a, chlorophyll-b, leaf area index, leaf rolling, ear yield, and interaction of irrigation × fertilizer on chlorophylla and b and grain yield per hectare was significant. The application of coated urea fertilizer increased 29.41, 15.06, 24.88, 34.11 and 14.88 percent on average in leaf area index, relative water content, leaf rolling, ear yield per hectare and fresh forage yield per hectare, respectively, compared to pure urea fertilizer. Also, the highest values of chlorophyll a and b and grain yield per ha were obtained from chitin coated urea fertilizer together with full irrigation (100% water requirement) and their lowest values were from the check fertilizer (without urea)with 60% water requirement. The reduction of 40% in irrigation decreased 15.89%, 31.02%, 42.85% and 40.33% in relative water content, leaf area index, leaf rolling and ear yeild per hectar, respectively, compared to full irrigation. The highest economic ear yield with average of 10238.6 kg/ha and 9853.3 kg/hawas obtained from full irrigation and chitin coated urea,respectively, and the lowest ear yieldwas obtained from 60% water requirement with check fertilizer treatment.

Lettuce is one of the most important leafy vegetables used primarily for fresh and salad applications. The purpose of this study was to investigate the effect of different levels of water and nitrogen on lettuce yield and find the best irrigation and nitrogen fertilizer practices for producing this crop in drip irrigation. Iceberg variety of lettuce was planted in 2018 with three irrigation treatments (I1, I2 and I3 to provide 100%, 80%, and 60% of crop evapotranspiration, ETa, respectively) and four nitrogen treatments (N1, N2, N3, and N4 to provide 105, 70, 35 and zero kg of nitrogen per hectare in total, respectively). In 2019, two irrigation treatments (I1 and I3) and two nitrogen treatments (N1 and N4) were used. The experiment had a randomized complete block design with three replications. The results indicated that the effect of irrigation and nitrogen treatments and their interactions on the marketable yield of lettuce; but the dry matter produced was only affected by irrigation and nitrogen treatments. Maximum marketable yield and dry matter production were 66.1 ton.ha-1 and 2728.2 kg.ha-1 for full irrigation treatment with 105 kg.ha-1 nitrogen (I1N1) treatment, respectively. The minimum marketable yield and dry matter were 37.5 ton.ha-1 and 1929.6 kg.ha-1 for 60% ETa treatment with 35 kg.ha-1 nitrogen (I3N3) treatment, respectively. The maximum and minimum irrigation water productivities for marketable yield were 21.63 and 15.38 kg.m-3 for I2N1 and I3N3 treatments, respectively. The linear and nonlinear production functions of yield-water and yield-nitrogen were obtained for lettuce variety Iceberg, which can be used in similar environmental conditions in research and practical applications.

Intensive cultivation has led to a rapid decline in organic matter and nutrient levels besides affecting the physical properties of soil. The sustainability of production systems has become an important issue throughout the world. This study assessed the effects of nitrogen fertilizer and vermicompost on chamomile's qualitative and quantitative yield. The investigation was conducted at the Research Fields of Ran Company in Firouzkouh, Iran, in the spring of 2017. Treatments consisted of 1) Control, 2) 100% nitrogen from urea, 3) 100% nitrogen from ammonium nitrate, 4) 75% nitrogen from urea and 25% from vermicompost, 5) 75% nitrogen from ammonium nitrate and 25% from vermicompost, 6) 50% nitrogen from urea and 25% from vermicompost, 7) 50% nitrogen from ammonium nitrate and 25% from vermicompost, 8) 25% nitrogen from urea and 25% from vermicompost, 9) 25% nitrogen from ammonium nitrate and 25% from vermicompost and 10) 100% nitrogen from vermicompost. The results of this investigation showed that the maximum plant height (67.03 cm) and plant weight (93.21 g plant-1) were obtained by 200 kg ha-1 urea. The application of 202.5 kg ha-1 ammonium nitrate + 1.5-ton ha-1 vermicompost, caused maximum flower diameter. The highest fresh flower yield (7539.45 kg ha-1), dry flower yield (1715.93 kg ha-1) and essential oil yield (6.95 kg ha-1) were obtained in plots that received 135 kg ha-1 nitrate ammonium + 3-ton ha-1 vermicompost. It seems using vermicompost could enhance the quantitative and qualitative characteristics of chamomile.

In order to investigate the effect of planting densities and different amounts of nitrogen on leaf greenness index and leaf area index, seed yield and oil yield, irrigation water productivity and nitrogen use efficiency in sunflower, an experiment was conducted as a split plot in the form of randomized complete blocks design with three replications in the research farm of Agriculture Institute in Semnan province in the spring of 2019. Plant density in four levels (4, 6, 8 and 10 plants per m2) as a main plot and the amount of nitrogen levels (0. 50, 100, 150 and 200 kg urea ha-1) as sub plot was considered. Leaf greenness index, plant height, 100-seed weight, seed nitrogen content and seed oil content were significantly affected by the simple effect of planting density, which decreased with increasing density of the above traits. Also, the nitrogen levels significantly affected the studied traits, so that with increasing the amount of nitrogen consumption, from control (0 kg urea ha-1) to 200 kg urea ha-1, the leaf greenness index increased by 15.3%. The highest amount of plant height, 100-seed weight and grain nitrogen were obtained in the treatment of 150 kg urea ha-1 and 14.13, 9.07 and 24.3% more than no application, respectively. Mean comparing the results of water use efficiency showed that at a density of four plants per m2 and an increase in nitrogen levels, along with increasing height and leaf area index, water use efficiency also increased, but higher levels of density led to smaller plant yield, less plant biomass and water efficiency were reduced. The highest nitrogen use efficiency was obtained in the density of 8 plants per m2 and no application of nitrogen fertilizer. Finally, maximum grain yield (4016 kg.ha-1) and oil yield (1827 kg.ha-1) were obtained by consuming 150 kg urea per ha-1 and density of 8 plants per m2.