ذرت

Multiple regression analysis and path analysis of maize grain yield with other agronomic traits to determine the most effective traits of the grain yield as well as analysis of genotype×trait interaction using the GGE biplot method, to evaluate the response of the hybrids to normal and water-deficit stress conditions based on the measured traits for determining high-yielding hybrids for both conditions, were carried out. In order to determine superior hybrids under normal and drought stress conditions based on agronomic traits and with the help of genotype×trait biplot analysis and also to determine traits affecting grain yield through multiple regression and path analysis, 18 maize hybrids were evaluated in a split-plot design based on the randomized complete block design in three replications and in two consecutive years.Two levels of irrigation were allocated in the main plots and maize hybrids in the subplots.In the path analysis of the grain yield with other studied traits, the number of kernel rows, the 300-grain weight and the number of grains per row under normal conditions, and the number of kernel rows and the 300-grain weight in the drought stress conditions had significant direct effects on the grain yield.The results of GGE biplot analysis of genotype×trait in both conditions showed that in normal conditions the two first components explained 72/28% and in water-deficit stress conditions 83/60% of the total variance.In both conditions hybrid SC704 was recognized as the ideal genotype.Hybrid SC704 ranked first as the most high-yielding hybrid in both conditions, and hybrid SC647 ranked next.

Due to the water limitation in Iran and the widespread use of maize in human and animal feeding, this research was carried out to evaluate the effects of different salicylic acid levels on some morphological traits and grain yield of this crop under drought stress during reproductive stages. A field experiment was conducted as a split-plot based on a randomized complete block design with three replications in 2020 to investigate the effect of salicylic acid (SA) levels (0, 1, 2 and 3 mM) on morphological traits, grain yield and yield components of maize under normal irrigation and irrigation disruptions at reproductive stages. Irrigation and SA levels were assigned to the main and sub plots, respectively. The results revealed that irrigation disruptions from initial flowering up to maturity caused a significant decrease in the mean plant height, ear length, grains per ear and plant, 1000-grain weight, grain yield, plant biomass and harvest index. Foliar spray of salicylic acid, especially with 3 mM concentration increased most of these traits as well as 1000-grain weight, leading to an improvement in grain yield per unit area. The 1000-grain weight, harvest index, plant biomass, ear length, grains per plant and ear had the highest positive correlation with grain yield of maize. Water supply during grain filling stage is necessary to obtain a higher yield in maize. Foliar application of 3 mM salicylic acid was the superior treatment for increasing maize yield under normal and limited irrigation conditions.

The aim of this study was to investigate the effects of planting date(13 May,10 June And 8 July) and corn cultivars(KSC400,KSC647 And KSC 704) on the yield and yield components in Karaj. An experiment was conducted as a split-plot design based on randomized complete blocks with four replications in the research farm of the University of Tehran. The results showed that the highest yield belonged to the second planting date (11.98 t.ha-1), the third planting date (11.56 t.ha-1), the first planting date (11.18 t.ha-1), respectively. The results revealed that in the first and third planting dates, corn grain yield was decreased due to the occurrence of the high daily temperatures in the reproductive stage. Furthermore, a coincidence of the decreasing temperatures with the grain filling period in autumn led to corn grain yield reduction. Due to the appropriateness of the reproductive stages in the second planting date, the length of seed abortion was decreased and the length and size of the ear, the weight of the ear, the number of seeds per ear, and grain yield were increased. The results revealed that the 400 cultivar (10.25 t.ha-1) in July, 647 (12.35 t.ha-1) in May and 704 (13.77 t.ha-1) in June had the highest yields in the study area. In addition, to reduce the frequency of irrigation and save water, it is recommended to cultivate medium and early maturing varieties of corn on 13 May and 8 July sowing dates, respectively.

In order to study different tillage systems, winter cover crops and their effect on improving soil quality and maize weeds, a split-factorial experiment using randomized complete block design was conducted at Agricultural Research and Education Center of Ardebil province (Moghan) during two years to evaluate the effect of winter cover crops, tillage and dosage of MaisTer Herbicide. Two types of tillage system in the main plot conventional tillage and no tillage. The cover treatments including vetch (Vicia villosa L.), Crimson clover (Trifolium incarnatum L), Rye (Secale cereale), barley (Hordeum vulgare L.), Rapeseed (Brassica napus) and no-cover crop, as well as reduced dosage of MaisTer® herbicide were placed in a factorial arrangement subplot. percentage of soil organic matter in the system no tillage was 13.72% higher than conventional tillage. Cover crops reduced the total winter weed density by more than 55% in both years compared to the control without cover crops. Yield of corn in the first and second year were 7.89 and 8.46 tons per hectare, respectively, and this increase in yield in the no-till system was 10.22 percent higher than the conventional tillage system. vetch increased corn yield by 30% more than other plants. Consumption of half dose of Meister regrowth herbicide at 3-4 leaves of corn did not differ statistically from its recommended dose. In general, cultivation of hairy vetch in the fall along with no-till method by applying half the dose of Meister herbicide in corn, can increase soil fertility, reduce corn weed density and production costs.

This paper was conducted to study the quantitative traits related to grain yield and to investigate the relationship between different traits and to select the most important quantitative traits affecting grain yield in maize hybrids.

The experiment was conducted in a randomized complete block design (RCBD) with three replications in the two cropping years of 2017-2018 in Shiraz region. sampling and taking notes were performed from the two middle rows.

Based on the combined analysis of variance at the probability level of 0.01, all hybrids had a significant difference. Also, the effect of hybrid year was significant in all traits except ear diameter. Based on the comparison of the mean performed by Duncan method, two genotypes KSC704 and KSC707 were identified as hybrids with superior rank. Based on the correlation analysis, grain yield had a positive and significant correlation with grain width and 1000-grain weight. Also, the results of the correlation diagram showed a positive and significant correlation between grain yield and grain length, 1000-seed weight, plant height, ear length and number of rows per ear. The drawn polygon diagram also showed that KSC705 genotype is more desirable than other genotypes. Based on the ranking chart of genotypes based on the ideal genotype, SC647 hybrid was identified as a hybrid with better desirability.

Conclusion :

Based on the studied traits, KSC704 and KSC705 genotypes were identified as better ranked hybrids and SC301 and SC302 genotypes were identified as unfavorable genotypes.

 Nowadays demand for producing agricultural products has been increasing. So to investigate the effect of tillage and planting pattern using crop residue for corn forage a research was carried out in the research field of in the Dezful city of Khuzestan province.

A split strip plot design was applied using 3 replications based on randomized complete block design. Treatments tillage methods at three levels (tillage, minimum tillage and no-tillage) was as the main factor and management of wheat residues (Chamran cultivar) at two levels (maintaining residues standing and removing all crop residues from the soil surface) was as a secondary factor.

The results were shown that conventional tillage under no residue and no-tillage under residue condition product the most and the least emergence rate of 3.73 and 1.96 respectively. Also conventional tillage under no residue used 10230 m3/ha compared to no-tillage covered by residue 6341 m3/ha (p≤0.01).No-tillage with an average of 2.74 and conventional tillage with 2.19 kg/m3 showed the highest and lowest physical efficiency of water consumption, respectively (p≤0.01).

The use and development of conservation cultivation systems (especially minimum tillage) in corn can help maintain conservation of production resources such as water, soil and the environment. The use of conservation tillage systems along with the preservation of residues at the soil surface, increasing moisture storage, reducing irrigation water consumption, increasing soil organic matter and fertility and saving labor and time spent on tillage operations can be a model suitable for planting corn.

The aim of this study was investigated the effect of weed interference on some growth indices and grain yield of corn (Zea mays L.), an experiment was carried out in a randomized complete block design with four replications during 2019 growing seasons at the Moghan region.

The experiment was included fourteen treatments; seven weed-infested and seven weed free treatments were applied at regular intervals (0, 10, 20, 30, 40, 50 and 60 days) after corn emergence in which weeds were allowed to grow until harvest and weeds were removed, respectively. Total dry weight of weeds, total dry matter (TDM), leaf area index (LAI), crop growth rate (CGR) and yield of corn were measured.

The results showed that all measured traits were affected by weed interference duration and weedcontrol period. Weed interference duration increased total dry weight of weeds and weed-free duration reduced total dry weight of weeds. Also, increase in weeds interference duration significantly reduced TDM, LAI, and CGR and grain yield of corn. On the other hand, TDM, LAI CGR and grain of corn increased by rising weed-free duration.

Considering of 10% yield loss, the critical period of weed control was 3 and 52 days after corn emergence, respectively. The weed interference duration had a significant effect on grain yield of corn and weed interference at the whole season. Weed interference reduced grain yield of corn.

This experiment was performed to evaluate the effect of organic amendment and growth-promoting bacteria on phytoremediation of maize under cadmium (Cd) stress.

This experiment was performed in the form of factorial in a completely randomized design with 4 replications. Experimental factors were: 1- biochar as a soil organic amendment at two levels (non-application and application (20 g.kg-1 soil), 2- Pseudomonas putida at two levels (non-inoculation and inoculation of bacteria) and 3- heavy metal levels (0, 25, 50, 75 and 100 mg Cd. Kg-1 soil). 

Cadmium in all concentrations had reduced the dry weight of roots and shoots, while biochar application and bacterial inoculation increased these traits; when the maximum shoot dry weight (9.43 g per plant) was observed by biochar application and inoculation of Pseudomonas putida and no cadmium contamination, which increased 45.30% compared to the control. The highest amount of available cadmium in soil, roots and shoots were 23.29, 33.90 and 36.25 mg/kg, respectively, which all three were obtained in the concentration of 100 mg Cd/kg soil. The lowest amount of bioconcentration factor (0.75) and bioaccumulation factor (1.03) were related to the synergistic treatment of biochar and Pseudomonas putida at the concentration of 25 mg Cd/kg soil, which decreased up to 17.90 and 10.62% compared to the control, respectively.

In order to study the effect of Plant Growth Promoting Bacteria and Mycorrhizae Fungi application as seed coinoculation on three late maturity maize single cross hybrids seed germinability and seedling vigour a laboratory research conducted. 

Experiment conducted as 18 treatments (3 single crosses × 6 seed inoculations) two factorial based on complet randomized blocks design by four rplications. Studied Plant Growth Promoting Bacteria were Azotobacter chroococcum, Azospirillum lipoferum, Azospirillum brasilence and Pseudomonas fluorescens and studied arbascular mycorrhizae fungi were Funneliformis mosseae and Simiglomus hoi. Also studied late maturity maize single cross hybrids were SC700, SC704 and a new promising late maturity maize single cross hybrid B73×K18. Effect of coinoculation of seeds by studied Plant Growth Promoting Bacteria and Mycorrhizae Fungi on germination ability and seedling vigour of studied late maturity maize single cross hybrids evaluated by germinability, mean germination time, coefficient of velocity of germination, mean daily germination, daily germination speed, seedling length, primary shoot length, primary root length, seedling dry weight, primary shoot dry weight, primary root dry weight and  seedling vigour Index measurement.  

The results revealed that except of mean daily germination and coefficient of velocity of germination, other studied traits affected by intractions of hybrids and coinoculation. Likewise,  revealed that application of an inoculant of  three bacteria combination and Glomus mossae have highest growth promoting effect on germinability and traits related to seedling vigour of all hybrieds and Azotobacter chroococcum and Azotobacter chroococcum+ Pseudomonas fluorescens and Glomus mossae seed co inoculation by those bacteria  have most growth promoting effect respectively. Also, revealed that studied characters of SC704 more than other hybrids affected by growth promoting effect of studied bacteria and mycorhizae and respectively B73×K18 and SC700 affected by studied Plant Growth Promoting Rhizobacteria and mycorhizae fungi stimulating effect and studied characters have high correlation among them. 

Based on this research results application of studied Plant Growth Promoting Rhizobacteria and mycorhizae fungi as seed coinoculation had considerable effect on studied late maturity maize single cross hybrids seed germination enhancement and seedling improvement. Therefore, application of them as commercial biofertilizer maybe possible through seed coating for maize cultivation development.

Since improving the efficiency of environmental resources utilization in intercropping is one of the essential strategies for achieving sustainable agriculture, Therefore, in order to assess some ecophysiological properties of maize S.C 704 in additive intercropping with mungbean, an experiment was conducted.  

The experiment was based on randomized complete block design with six treatments and four replications in Dezful region during the summer of 2018. Experimental treatments consisted of different additive intercroppingof maize-mungbean intercropping (adding 10%, 20%, 30%, 40% and 50% of optimum density of mungbean to optimum maize density) and a pure stand of maize (control).  

The results showed that the effect of different maize -mungbean additive intercropping treatments on leaf area index, leaf area duration, light absorption, crop growth rate, dry matter accumulation and light use efficiency was significant. But the relative growth rate was not significantly affected by the treatments. In this study, with increasing in mungbean density, the evaluated traits in all intercropping treatments were higher than that of pure maize. However, the additive intercropping treatment of maize+40% mungbean utilized higher leaf area index (5.28), leaf area duration (217 LAI-day), absorption of photosynthetically active radiation (18.12 MJ/m2), Crop growth rate (30.14 g/m2/day) and relative growth rate (0.0838 g/g/day) compared to the other treatments, resulting in the highest dry matter accumulation (1996.50 g/m2) and consequently the highest radiation use efficiency (2.91 g/mJ).  

In general, maize+40% mungbean treatment can be introduced as the best maize-mungbean additive intercropping system, regarding environmental resources consumption and dry matter production.

The development of energy supply from biomass to reduce greenhouse gas emissions has led to focus on producing important crops from energy perspective which culminated in water consumption increase. Therefore, in this study for analyzing the water and bioenergy nexus, an index called water footprint was used. In this regard, information about maize in the plains of Khuzestan province, was collected. Based on the calculations, it was found that the water footprint of maize crop in the province has an average of 3355.6 m3/ton and the biomass water footprint is equal to 214.9 m3/ton. Moreover, in the study of water footprint of maize biomass, it was found that the highest and the lowest water footprints devoted to Behbahan plain (27.1 m3/GJ) and Abbas Abad plain (10 m3/GJ), respectively. Accordingly, Khuzestan province with an average of 13 m3/GJ, has better condition in terms of water consumption in compare to countries such as Zimbabwe, Brazil and the United States with a water footprint of 200, 39 and 18 m3/GJ, respectively. Mapping the biomass energy production potential with the water footprint approach also showed that water footprint in southeastern plains of the province (especially Behbahan, Omidieh, and Hendijan) are in the interval between 12 up to 27.1 m3/GJ and have low priority for biomass production. In contrast, the northern and eastern plains (especially Abbas Abad, Andimeshk, Sidon and Qaleh Tal) with bioenergy water footprints of 10 to 10.9 m3/GJ have high priority to the use of maize biomass for energy production.

In order to investigate the response of grain yield, plant height and phenological traits of maize hybrids (Zea mays L.) to planting date, a factorial experiment was carried out based on complete randomized block design with four replications during two growing seasons (2013-2014) at Moghan Research Station. Treatments consisted of two planting dates (May 1 and June 25) and five maize hybrids (namely SC704 and SC720 from a late maturing group, TWC600 and SC647 from mid maturing group and SC301 from early maturing group). The results of statistical analysis showed a significant difference between years, planting dates and hybrids. The highest grain yield and plant height were related to SC704 and SC720. The results showed that the planting date on May 1 increased plant production compared to June 25. The highest average of days to physiological maturity related to planting date was May 1. SC704 and SC301 had the highest and lowest average of days to flowering and days to pollination in two different planting dates during two growing seasons (2013-2014) in Moghan region, respectively. Multiple regression analysis by stepwise method showed that in regards to days to pollination and days to physiological maturity with grain yield of maize hybrids there was a significant positive association (P<0.01) in two different planting dates (May 1 and June 25) during two growing seasons (2013-2014) in Moghan region. In conclusion, The phenological traits with grain yield can be used to select the best maize hybrids for different planting dates.

The effect of pre-sowing treatments and nitrogen rates on yield and yield components of corn (SC704) in two planting density, were assessed by field experiment as split-split plots based on randomized complete block design (RCBD) with four replications, during 2013-2014 growing season in Karaj. Four pre-sowing treatments, Fallow, Manure, green manure Perko PVH and Buko from brassicaceae family were main factors, three rates of nitrogen as 120, 240 and 360 kg.ha-1 were sub-factors and two planting density (8 and 12 plants.m-2) were sub-sub factor. The results illustrated that the effect of pre-sowing treatments and nitrogen rates interactions and plant density on biological yield, number of rows per ear, number of kernels per row, number of kernels per ear, grain yield per unit area and grain weight were significant. The highest rate of all variables were obtained from the Perko PVH, by consuming of 240 kg N.ha-1 and plant density of 8 plants.m-2. Pre-sowing consuming of with Perko PVH 240 kg N.ha-1, due to producing highest grain yield is recommend for Karaj region.

Nitrogen fixation ability in free-living condition is one of the properties of diazotrophic bacteria that Azotobacter is one of the famous genera of diazotrophs. Evaluation of nitrogen fixation efficiency can be measured by different methods, such as difference method and plant inoculation. Thus, N2 fixation ability of 18 bacterial isolates such as Azotobacter was measured using completely randomized design with three replications. Bacterial liquid culture was added to bagasse- perlite as a carrier and disinfected seeds were inoculated with prepared inoculants. Treatments were included, negative controls (including carrier without bacteria and without carrier), positive controls (using urea equal to 50% and 100% of fertilizer recommendation) and pots inoculated with bacterial inoculants. Results showed that expect wet weight and nitrogen concentration of root, all measured parameters were significantly influenced by treatments. Other measured parameters such as shoot wet and dry weight, root dry weight, total wet and dry weight, height, diameter and chlorophyll index, were significantly influenced by 50% and 100% fertilizer treatment and highest mean was recorded in these treatments, while among bacterial treatments A. chroococcum 14SP-Ι, A. chroococcum 16SP-2 and Pseudomonas sp. 34SP-Ш were effective. The highest total nitrogen content and nitrogen translocation factor were observed in plants which inoculated by A. chroococcum 16SP-2 that caused an increasing of 32% and 148% compared to negative control (without carrier and bacteria). Also, the highest nitrogen fixation efficiency was measured in 16SP-2 isolate equal to 39.47% by difference method.

The effects of two mycorrhizal fungi species on grain yield, yield components, relative water content (RWC) and chlorophyll content in maize (SC704) under water deficit stress, under field experiment was assessed out as a split plot design with four replications in 2016 at Moghan Research Station. Water stress treatments included commonly available irrigation water referred to as control and the interrupted irrigation before flowering as the main plot, and two different mycorrhiza species, including Glomus mosseae and Glomus etunicatum and also a control (without any inoculation) as sub plots. Results showed that water stress significantly decreased grain yield, yield components, relative water content (RWC) and chlorophyll content. The applied water deficit stress reduced grain yield, yield components, RWC and chlorophyll content about 14, 13, 20 and 13 percent, respectively. Mycorrhizal fungi increased plant height, RWC and chlorophyll content in maize. Interaction between water stress and strains of mycorrhiza had only an impact on grain yield and 100-seed weight. The maximum grain yield and 100-seed weight were recorded in plots irrigated in normal condition and inoculated with G. mosseae species on control irrigation. Based on the results of this study, for enhancing grain yield and chlorophyll content using mycorrhizal fungi especially, G. mosseae species was recommended.

Minimal soil movement and retention of rational amounts of crop residue in crop rotation are the principles of conservation agriculture system. In order to study the effects of tillage method and residue retention on yield, yield components and water use efficiency of forage maize and some soil chemical characteristics in water stress conditions, this experiment conducted in Jolg-e-Rokh research station (Torbat-e-Heydarye, Razavi Khorasan Province) in 2015. Used farm, has been managed under the conservation agriculture system from 2012 (with similar treatments of this experiment and fixed plots in wheat-clover-beet-barley crop rotation). The experiment was conducted as split split plot in randomized complete block design with three replications. Treatments were Tillage method (no tillage, minimum tillage and conventional tillage), residue retention rate (0, 30 and 60 percent) and water stress (50, 75 and 100 percent of irrigation water). Results showed that various tillage methods were significantly effective on yield, and minimum tillage in compare with conventional tillage, increased forage yield over %6. Residue retention treatment did not have significant effects on yield and another studied characteristic but water stress treatment had significant effects on forage yield, forage quality index, stem diameter, water use efficiency and tasseling period. Applying minimum tillage with %60 residue retention with 41180 kg.ha-1 forage yield and 7.2 kg.m-3water use efficiency, was a good solution in comparison with other methods.

Phosphatic microbial fertilizers (PMFs) which produced from organic (Bagasse) and chemical (Rock phosphate and Sulfur) materials with combination of phosphate solubilizing bacteria (PSB) are taking more concerns in recent researches. These products are being used in two forms; granular or powder, to meet plant P demand. But application of sulfur in this formulation was the main reason of this research, whether the application of S in this context is useful or not? According to this main question, application and non-application of elemental sulfur in produced PMFs were evaluated in this study. This PMF was made after preparing the initial appropriate population (107 CFU/g) of the bacteria Pseudomonas fluorescens in the context of rock phosphate (45 g), bagasse (30 g) and sulfur (15 g). The treatments included the control (without adding any bacteria or PMF), microbial fertilizers bed without adding bacteria (or carriers) and PMFs in two levels of consumption (0.6 g and 1.2 g) based on soil analysis test. The results of greenhouse experiment showed that the addition of sulfur in the formulation of microbial fertilizers not only doesn’t have any inhibiting effect on bacteria but also increases all the indices of growth and plant nutrient. Application of sulfur in phosphatic microbial fertilizers had significant increase on total wet and dry weight of shoot (50.48 and 20.62 %, respectively) and root (41.85 and 42.47 %, respectively), the content of phosphorus, potassium, iron and zinc in the root (45.86, 58.01, 45.09 and 76.33%, respectively) and shoot (28.66, 29.79, 50.08 and 67.23%, respectively) of corn variety S.C.704. Inoculation with microbial fertilizers and plant growth promoting bacteria P. fluorescens with chemical element sulfur led to rhizosphere colonization and caused an increasing effect on plant growth and its nutrition. It seems that addition of sulfur not only has not a negative effect on P. fluorescens bacteria but also the positive effects of this fertilizer have improved.

Though chemical fertilizers increase crop production; their overuse has hardened the soil, decreased fertility, strengthened pesticides, polluted air and water, and released greenhouse gases, thereby bringing hazards to human health and environment as well. Using of chemical fertilizer in agriculture has a history of more than fifty years in Iran. Recently, nitrogen fertilizers consume more than 61 percent of the chemical fertilizer in our country. Globally, the role of chemical fertilizers especially nitrogen fertilizers in agricultural production has been widely studied over the past 50 years, and in our country a considerable amount of research in universities has been dedicated to studying in this field. Meta-analysis is a method for analyzing the results of various studies on a subject. In fact, meta-analysis is a type of research on other research to re-examine the various studies carried out on a particular topic, compare them statistically and, using specific statistical techniques, the results of all those studies combine into a single result. Experiments on the effects of nitrogen fertilizers on cereals yield have a long history in Iran. However, because of high variation in the results, a final conclusion is not readily achieved.
In this study, the researches of the effect of different levels of nitrogen fertilizers on yield and yield components of cereals (wheat, corn and rice) over the past 20 years have been investigated. These studies included a variety of scientific-research articles. So, 46 papers were selected and the information was extracted from them. To overcome such a difficulty meta-analysis was used to combine and re-analyze the data of independent experiments. For this, 46 published papers related to nitrogen application on cereals including 23, 14 and 9 papers, respectively on wheat, corn and rice were selected based on criteria to satisfy the required data for meta-analysis. Fertilizer application rates for wheat, corn and rice varied in the range of 20-250, 25-275 and 10-90 kg.ha-1 N, respectively.
About 86% of the experiments used treatments between 25 and 150 kg.ha-1 nitrogen, and the frequency of nitrogen levels above 200 kg.ha-1 was very low in corn experiments. In the case of wheat, the range of nitrogen levels in the experiments was between 20 and 250 kg.ha-1. In rice, the range of nitrogen uptake was far more limited than wheat and corn, it is between 10 and 90 kg ha-1. On average in all nitrogen levels, grain yield of wheat, corn and rice compared to control were increased by 2477, 4699 and 1509 kg.ha-1, respectively. Meta-analysis results showed that nitrogen fertilizers significantly increased both grain yield and Biological yield of the studied cereals. However, harvest index was not statistically affected. Maximum grain and biological yields were attained by 50-100 and 100-150 kg.ha-1 N, respectively. Meta-analysis was also conducted for each crop separately. The results indicated that optimal nitrogen levels for the grain and biological yields were 75-100 and 100 kg.ha-1 N except corn. For corn maximum amount could be achieved from 50-100 kg.ha-1 N for grain yield and from 50-100 kg.ha-1 N for biological yield. For rice, maximum of grain and biological yields were reported by 75-90 kg.ha-1 N. The studied cereals harvest index showed no significant response to nitrogen fertilizers.
The results of this study showed that despite the long history of using this inputs in the agricultural sector, the optimal use is still unclear. In this study, statistical comparisons between fertilizer levels were performed, while the ecological dimensions of nitrogen application were also significant. Further studies can compare types of efficacy, soil health and environmental aspects of nitrogen use and other chemical fertilizers, provide a wider range of possibilities for sustainable field management and sustainable management of the country.

Copper (Cu) is a necessary micronutrient for crops and its availability in calcareous soils is low. Phytoavailability of Cu depends on the relative distribution of different chemical Cu forms in soil, which is function of soil properties. In this greenhouse research, total soil Cu fractionated into different forms by sequential extraction procedure in 21 surface soil samples of East Azarbayjan province that varied in physical and chemical properties. According to the results, different Cu fractions concentration were as: Residual copper (Cu-Res) > Crystalline Fe oxides bound (Cu-CFeOX) > amorphous Fe oxides bound (Cu-AFeox) > Oranically bound (Cu-OM) > Carbonates bound (Cu-Car) > soluble 笗Ⅺ砞榹 (Cu-Ex) > Mn oxide bound (Cu-Mnox). Correlation coefficient showed that the corn shoot dry matter, corn shoot copper concentration and corn shoot copper content hadn’t significant correlation with soil copper forms. Cu-Car, Cu-MnOX, Cu-AFeOX, and Cu-Res had a significant relationship with corn shoot and root copper concentration.

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.