جستجوی مقالات مرتبط با کلیدواژه « ذرت » در نشریات گروه « کشاورزی »

Considering the limited natural resources and the negative effects of inappropriate use of these resources on both human health and environment, addressing the patterns of energy consumption remains vital (Baran and Gokdogan, 2017; Ozkan et al, 2004).

This study was conducted at the research farm of Shahid Chamran University of Ahvaz in the summer of 2018. Experimental design was split-plot based on randomized complete block design with three replications. Main plots consisted of agriculture production systems; intensive (all inputs e.g., fertilizers, herbicides, and pesticides were chemical), sustainable (a combination of organic and intensive methods were used to manage this farming system), and organic (in this farming system, all inputs were organic and biological, no chemical fertilizers were applied. control of weeds was done mechanically). Sub plots consisted of three crops; corn (cereal), mung bean (legume) and sesame (oil seed). In this study, energy efficiency indices were calculated by measuring the energy equivalent of all inputs and outputs.  

Results showed that the highest and lowest grain yields for corn, mung bean and sesame were obtained in the intensive and organic systems, respectively. The lowest (1.18) and highest (3.69) energy use efficiencies were belonged to intensive sesame and organic corn, respectively. The highest amount of energy consumed (34396 MJha-1) was observed in intensive corn and the lowest with the value of 8247 MJ ha-1 was belonged to the organic mung bean. Additionally, intensive corn presented the highest (94045 MJ) output energy. On the other hand, organic mung bean showed the lowest value of the output energy (15279 MJ). Intensive corn and organic sesame had the highest and lowest amounts of net energy indices with the values of 59649 and 7032, respectively. Although corn yield in the organic system was nearly 30 percent lower than in the intensive system, energy consumption for organic corn was 50 percent lower than for intensive corn

To design an appropriate agroecosystem, it is necessary to consider a collection of agroecological indices e.g., energy use efficiency, net energy, energy utilization index, special energy, as well as crop production history and agricultural culture (human resource productivity index, agrochemical energy, greenhouse gas emission) to find a balance between both factors based on each region.

Maize cultivar Chavoosh or single cross 380 (SC380) as a new early-maturing hybrid is produced from the crossing between KE76009/312 and K1263/1 maize inbred lines. In the preliminary yield trial, the new hybrid with 11.92 tha-1 grain yield in Karaj region in 2006 was included in the group of superior hybrids and was selected for studying in the next step in the semi-final yield trial in 2007. At this stage, the grain yield mean of the new hybrid in four regions (Karaj, Mashhad, Shiraz, and Kermanshah) was 12.18 tons per hectare that showed 910 kg per hectare increase in grain yield compared to the control cultivar Dehghan. The average grain yield of new hybrids in eight regions during 2014 and 2015 was 11.54 tons per hectare in the final stage experiment and showed the superiority of 750 kg compared to the control cultivar Dehghan. This superiority became more apparent because the new hybrid had 100 days growth period and was nine days earlier than the control hybrid Dehghan. The promising new hybrid also showed higher grain yield stability using GGE-biplot stability methods and Lin and Binns index. This new hybrid with an average grain yield of 12.28 tons per hectare showed a yield superiority of 1.15 tons per hectare compared to the control cultivar Dehghan in the yield trial in five regions (Karaj, Mashhad, Isfahan, Shiraz, and Kermanshah) in 2016. In the research-extension experiments in the Kermanshah region in 2016, the new cultivar (Chavoosh) and control cultivar Fajr produced similar grain yield (7 tons per hectare) that was lower than the control cultivar single cross 704, but for early-maturing hybrid Chaavosh less irrigation (in average, 2 to 3 times) was done. Therefore, it is estimated that using Chaavosh hybrid under pressurized irrigation systems can save about 800 to 1200 cubic meters, and under traditional irrigation systems can save about 1600 to 2400 cubic meters of water per hectare. In general, Chaavosh hybrid is recommended for spring planting in temperate and cold temperate regions due to its shorter growing period, lower water consumption and also its good grain yield. It is also recommended for summer planting in temperate regions.

One of the environmentally friendly methods of weed control in cropping syastems is using of cover crops. Cover crops can reduce or control weeds through different mevhanisms such as physical suppression (suffocation of weeds), ecological suppression (competition for limited resources of nutrients, water, and light), and chemical suppression (emission of allelochemicals).

To investigate the effect of monoculture and intercropping of cover crops on weed control and grain yield and yield components of corn (Zea mays L. cv. Kousha), a randomized complete block design with four replications was used in the research farm of faculty of agriculture and natural resources of Mohaghegh Ardabili University in ardabil, Iran, in 2018-9 and 2019-20. The experimental treatments included: triticale (×Triticosecale Wittmack) and daikon radish (Raphanus sativus var. Longipinnatus) as monocultures, intercropping of triticale + daikon radish with a control treatment (without cover crops).

The results showed positive effect of triticale monoculture on reducing the density of lamb’s quarters (Chenopodium album), pigweed (Amaranthus retroflexus), and wild mustard (Sinapis arvensis) weeds by 36.7%, 50% and 53.8%, respectively. The highest grain yield (3782.5 kg.ha-1) and number of grain.ear-1 (444.8) of maize were obtained in triticale monoculture. The results showed that triticale monoculture had the most desirable weed control efficiency index (44.1), Simpson index (0.61), Shannon-Wiener index (1.33) and Margalef’s species richness index (1.21).

Based on the results of this experiment, the success of the intercropping of triticale and daikon radish on controlling weeds density and improving maize grain yield was related to suitable density of the plant species used in this experiment. Triticale monoculture, grown in winter, can be considered as an effective cover crop for weed control and improving maize grain yield in Ardabil and similar environmental conditions.

This study aimed to investigate the impact of foliar application of urea fertilizer (Ure Phit) during the reproductive growth stage on the yield and grain quality of two corn varieties in the year 2019, conducted in a field in Eslamabad-e-Gharb County. The experiment was carried out as a factorial based on a randomized complete block design with four replications. The experimental factors included two single cross hybrids, 703 and 704, and five levels of Ure Phit foliar application (0, 0.5, 1, 1.5, and 2 L ha-1). The foliar application was performed at the beginning of the reproductive growth stage. The results showed that increasing the nitrogen fertilizer concentration led to an increase in leaf area index, yield components, overall yield, and grain protein percentage and yield. The highest leaf area index, number of grains per ear, grain yield, and grain protein yield were obtained at the concentration of 2 liters per hectare of Ure Phit, which showed an increase of 33.6%, 21%, 41%, and 173% respectively compared to the control treatment. In both varieties, foliar application during the reproductive growth stage led to an increase in leaf area index and leaf area duration, enhanced photosynthesis, improved grain yield components, and ultimately increased corn grain yield. The results indicated that the application of 2 liters per hectare of Ure Phit not only improved grain yield but also significantly enhanced grain quality.

Khuzestan, as one of the most important corn-producing provinces of Iran, lacks improved cultivars compatible with extremely hot and dry conditions and relies on foreign cultivars, including the old single cross 704 variety. To prepare suitable cultivars for Khuzestan, lines should be produced and evaluated in the region that can be used in the production of hybrid and open-pollinated cultivars.

To identify and improve the important and effective traits on maize grain yield, 289 corn lines, which were bred in Khuzestan, were crossed with the hybrid single cross 704 and evaluated in two cropping seasons (summer 2016 and spring 2017). The experiment was carried out with a simple lattice square design of 17 × 17 and two replications at the Safi-Abad of Dezful Agricultural Research Center in 2016 and 2017. The traits measured from the growing stage to harvest were plant height, tassel length, tassel branch number/plant, stem diameter, number of leaves / plant, ear diameter, grain depth, ear length, number of rows/ear, grain number/row, 100-grain weight, grain yield, biological yield, and harvest index based on the guidelines of the corn and fodder plant department of the Iranian seed breeding and preparation research institute. The yield based on 14% seed moisture along with other traits was measured and calculated from the two middle lines of each experimental plot. The genetic parameters in this research were calculated using the mathematical expectation of the mean square as the basic design of random complete blocks in the form of genetic relationships. To analyze the correlation between the traits and to identify the common factors affecting the studied traits, decomposition into factors was used with the principal component analysis and varimax rotation. Eventually, the analysis of variance (ANOVA) of data and calculation of correlation coefficients between variables were done using SAS Ver 9.20 software and analysis into factors with StatGraphics Ver 19.0 software.

The results of ANOVA showed an acceptable genetic diversity among promising maize lines in terms of all studied traits, except for ear length, number of rows/grain, and number of grain/row. The results of the composite analysis in two cropping seasons revealed that the effect of genotype was significant on all studied traits at the level of 1%, suggesting significant genetic diversity among the studied genotypes for all traits. The significance of the genotype × season interaction effect for all studied traits at the 1% level indicates the different responses of genotypes in summer and spring. The highest and the lowest genetic and phenotypic variances in summer and spring belonged to biological yield and seed depth traits, respectively. The ranges of genetic diversity in the studied traits in summer and spring ranged from 1.96 to 32.72 and from 7.63 to 29.88, respectively. Among the studied traits, the highest genetic and phenotypic diversities were observed in the number of tassel branches/plant trait (32.72 and 33.35, respectively). The highest heritability rates in spring were observed for biological yield (97.69%), grain yield (97.43%), grain depth (97.06%), ear length (96.30%), and plant height (95.74%). On the other hand, the highest amount of heritability along with the highest amount of genetic improvement was observed for the biological yield and grain yield traits, both of which can be considered the most important criteria for selecting parental lines in breeding programs based on this study. The results of the analysis of correlation coefficients for the studied traits in summer indicated that the grain number/row (0.81), biological yield (0.72), ear diameter (0.62), and grain depth (0.52) produced medium to high grain yields among the studied traits. In spring, the biological yield (0.86), 100-grain weight (0.65), grain number/row (0.64), ear length (0.64), and ear diameter (0.63) had medium to high effects on the seed yield.The results of analysis in the factor analysis in summer and spring revealed that five hidden and independent factors justified 71.40 and 72.27% of the total data changes, respectively. Five hidden factors for summer were the share of grain yield from the total dry matter (33.10%), plant height factor (15.80), ear diameter component factor (8.80), tassel height factor (7.50), and grain weight factor (7.20).

The two factors, namely the share of grain yield from total dry matter and the plant height factor, account for more than 61% of the total justifiable variation of 14 traits in 289 lines. These two factors enable us to define and recognize differences and similarities between the lines that grow in spring conditions in Khuzestan.

In this research, the effectiveness of five organic matter treatments were investigated to determine the amount of soil organic matter, rhizosphere fungal and bacterial population. Microbial population in rhizosphere and nutrients concentration in the aerial part of corn were carried out in the form of a randomized complete block design in three replications. Before planting maize, soil organic matter was measured before and after adding five organic matter treatments for one year. Then, maize was planted and harvested before it reached seed production, and the concentration of some nutrients in the aerial part of maize was determined. Also, the bacterial and fungal populations were determined in the rhizosphere and non-rhizosphere soils. The results showed that the largest population of rhizospheric bacteria in the treatments of Leonardite (231×104 cfu g-1 soil), fulvic acid (229×104 cfu g-1 soil) and calcium lignosulfonate (218×104 cfu g-1 soil) and the largest population of rhizospheric fungi in the treatment of calcium lignosulfonate (263×103 cfu g-1 soil) was observed to show a significant increase compared to the control treatment. The highest maize leaf nitrogen was observed in the treatment of fulvic acid (35.78 g kg-1) and calcium lignosulfonate (33.9 g kg-1), and the highest leaf phosphorus was observed in the treatment of fulvic acid (4.27 g kg-1) compared to the control treatment. In the treatments of fulvic acid, calcium lignosulfonate, and Leonardite, the highest amount of potassium was measured, and in the treatment of calcium lignosulfonate, the highest amount of calcium and magnesium was measured. Leaf sulfur was the highest in Leonardite treatment, but there was no significant difference with calcium lignosulfonate and fulvic acid treatments. The amounts of leaf micronutrients were the highest in the fulvic acid treatment, but iron and copper in the leaves were also the highest in the calcium lignosulfonate treatment.

Maize (Zea mays L.) is the third most important cereal after wheat and rice, which accounts for 26% of total cereal cultivated area and 37% of their production. Maize is a valuable raw material for extracting oil, starch, alcohol, glucose, plastic, lactic acid, acetic acid, acetone and paint, and it is possible to made paper, cardboard, and nitrocellulose from its stalks. As an important nutrient, phosphorus plays important role in energy transfer, photosynthetic oxidation-reduction reactions, as well as in biochemical compounds including nucleic acids, structural proteins, enzymes, and signal transmission. Due to the predominance of calcareous soils with high pH in arid and semi-arid agricultural climates, the amount of available phosphorus is limited. In order to increase available phosphorus for plants, large amounts of phosphorus chemical fertilizers are needed regularly. However, a large amount of phosphorus in fertilizers may be converted to insoluble phosphate, immediately by reaction with calcium in the soil after its application. On the other hand, indiscriminate use of phosphorus chemical fertilizers leads to many environmental problems such as surface runoff of phosphorus, eutrophication of aquatic ecosystems, reduction of biodiversity and abnormal changes in soil salt concentration and pH. Breeding cultivars that absorb phosphate or phosphorus more efficiently is one of the solutions to deal with the stress of phosphorus deficiency as a trait with low heredity. The use of selection indices can be an effective method for the indirect selection of traits with complex genetics.

93 maize genotypes prepared from different research centers were evaluated in terms of agro-morphological traits under normal and phosphorus deficit conditions using completely randomized design with three replications in the crop year 2016-2017 in an open area conditions. For this purpose, after analyzing the soil of different regions, soil with low phosphorus content (7.240 mg/kg) was selected and the pots (15 kg) were filled with soil and sand in a ratio of two to one. Usable soil phosphorus was determined by the Olsen method in the soil science laboratory of Urmia University. In both optimal and phosphorus deficit conditions, soil was strengthened with nitrogen fertilizers (in the amount of 9 g/pot (during three stages during the growth period)), potassium sulfate (in the amount of 13.5 g/pot), Sequestrin (1.5 g /pot), manganese sulfate (0.225 g/pot), zinc sulfate (0.99 g/pot), copper sulfate (0.3 g/pot) and boric acid (0.21 g/pot). In optimal conditions, phosphorus fertilizer in the form of triple superphosphate was added to each pot in the amount of 6 g/pot. Phosphorous fertilizer was not added to the soil in the phosphorus deficit conditions. With the beginning of the tasseling stage, various agro-morphological and chemical traits were measured. In the physiological maturity stage, the ears relating to each replication were separated from the plants. Seed yield per plant was determined by separating the seeds on the ears of each plant and weighing it. In order to select the desired genotypes, four selection indexes including Smith-Hazel, Pesek-Baker, Brim and Robinson indices were calculated. In this study, the same weight was considered for the attributes, which is done in this way in most studies. To select the best selection index, different criteria, including the genetic gain of traits (∆G), expected gain (∆H) and relative efficiency of selection index (RE) were calculated.

According to analysis of variance results, the effect of genotype and stress was significant on all studied traits at the probability level of 1%. Also, the interaction effect of genotype × stress was significant on all studied traits except for flag leaf length (FLL), flag leaf width (FLW), number of leaves (NL), plant height (PH), stem diameter (SD), ear length (EL), number of rows per ear (RpE), number of grain per row (GpR), ear diameter (ED) and 100 seeds weight (HGW). In the normal conditions (without stress) in the Smith-Hazel index (optimal index), the highest coefficient (7.21 and 3.98,) was observed in FLW and ear length (EL) traits, respectively, and the lowest ones (-3.03) was observed in RpE trait. In the phosphorus deficit conditions, the highest coefficient (3.91) was observed in EL and the lowest ones (-5.35) was observed in RpE trait. In the Pesak-Baker index, under normal conditions, the highest coefficient (5.64) was observed in GpR trait and the lowest ones (-9.28) was observed in EL. In phosphorus deficit conditions, the highest coefficient (8.49) was seen in FLW trait, followed by EL (4.53) and the lowest ones (-2.17) was observed in RpE. The highest coefficient in Robinson's index under normal conditions was 2.21 for LW, which was -5.91 for that under phosphorus deficit conditions. In this index, the lowest coefficient was seen in RpE (-0.92). In Robinson's index, under phosphorus deficit conditions, the highest coefficient (1.46) was seen in EL, and the lowest ones (-5.92) was seen in FLW, followed by RpE with a value of -2.13. The Smith-Hazel index with expected gain (∆H) value of 296.306 and 229.374, and relative efficiency of (RE) of 1.0011 and 1.0839 and the Brim with expected gain (∆H) value of 296.217 and 233.083, and relative efficiency of selection index (RE) of 0.9995 and 1.0836, in normal and phosphorus deficit conditions, respectively, were the best indices. Under both normal and phosphorus deficit conditions, biomass yield, seed yield, and plant height had the highest coefficients for these indices. Based on both indices, genotype with cod number 7 and the genotype with cod number 10 are introduced as superior genotypes under normal and phosphorus deficient conditions, respectively.

In general, the results of present investigation showed that in both normal and phosphorus deficit conditions, selection based on the Smith-Hazel and Brim indices will increase the biomass yield, seed yield and plant height due to their highest relative efficiency and expected gain. The selected genotypes after validation at the molecular level with different technologies, such as studying the expression of genes involved in tolerance to phosphorus deficit conditions using Real time PCR, can be used in the production of hybrid varieties as a way to reduce the use of phosphorus fertilizers.

Agriculture is the largest consumer of fresh water in the whole world. Currently, almost 11% of the Earth’s total land surface is arable, which is expected to reach 13% by 2050. Roughly 17% of these lands are subject to modern form of irrigation management, which constitutes about 30-40% of the gross agricultural output. Reducing water consumption and increase water productivity in agriculture, requires a correct understanding of the biological response of crop to water. The ever-increasing growth of the population and the limitation of fresh water resources have led irrigation experts to new and efficient approaches in making decision to increase water productivity. The lack of scheduling in irrigation or their incompatibility with weather conditions, soil, irrigation system, agricultural restrictions and different phenological stages of crop, has caused severe losses in irrigated fields. Crop modeling and field data measurement can help irrigation experts improve irrigation scheduling in field and reduce water losses. Coupling in-situ measurement and crop modeling during the growing season is one of the useful solutions to improve irrigation scheduling in different farm conditions. In this paper, AquaCrop was calibrated for maize (Zea mays L.) in research farm of Ferdowsi University of Mashhad with comprehensive dataset. Variations of soil water content at different depths and also different growth indices was monitored during one growing season. The main novelty of this research is the targeted use of AquaCrop software to reduce water consumption by knowing the phenologically sensitive stages.

In-situ and in-lab measurements along with plant modeling, have been the two main parts of this research. First, the input files of the AquaCrop software were prepared and calibrated for maize during one growing season. The outputs of software including variations of moisture, biomass produced during the growing season and final yield were compared with the values measured in the field. After ensuring the accuracy of calibrated software, an improved irrigation scheduling was investigated. Subsequently, by means of crop modeling, the sensitive intervals of the crop to soil water stress as well as the thresholds of yield reduction in different stages of growing season were determined with the aim of improving irrigation scheduling in maize field. Biomass reduction, dry yield production, and the changes in water use efficiency during the growing season were investigated according to different amounts of moisture reduction in root zone, and irrigation scheduling was fulfilled by applying stress to less sensitive stages. The software was first run in Net Irrigation Requirement mode. Then, different amounts of drought stress were applied to each of the growth stages of the crop, and the other stages were kept constant in non-stressed condition. Dry yield and biomass reduction as well as water productivity changes were obtained for each stage. According to the threshold values and the amount of yield reduction at each stage, it is possible to fine-tune the time and amount of applying stress to crop. Furthermore, according to the moisture profile of the root zone, the drained water was significantly reduced in field. In this research, in order to increase accuracy in moisture measurement and prevent errors, an equation was developed to convert the mV output of sensor to volumetric moisture. At each moisture measurement, the PR2 sensor reports a number in mV for each depth, which is converted to volumetric moisture using device's conversion equation. This equation can vary according to field and soil condition. To develop the conversion equation, six same pots with a height of 40 cm and diameter of 30 cm were filled with the desired field soil, and the access tubes were placed horizontally inside them. The soil inside these pots was completely saturated and exposed to air for drying. During the drying period of the pots, the soil moisture was measured regularly using PR2 sensor and at the same time by weight method. After these measurements, calibration curves for PR2 sensor were obtained using the alpha mixing method for different depths.

The Pearson correlation coefficient for measured and simulated moisture by software, was 0.84 and the root mean square error was 12 mm. Also, the value of Pearson correlation coefficient for measured and simulated values of biomass was equal to 0.99 and mean square root of error was 1.3 ton/ha. The results showed that the vegetative stage of crop was sensitive to drought stress and caused a significant yield reduction at the end of the growing season. The stage of germination and flowering were less sensitive, such that the decrease of moisture up to 12.3% compared to the Net Irrigation Requirement mode would not change the final yield of the crop. The improvement made in the field resulted in no change in the amount of biomass and dry yield (0.38% increase in biomass and 0.52% increase in dry yield), at the same time 26.6% decrease in depth of irrigation water, 85.6% decrease In drainage and increasing the efficiency of evapotranspirated water, it has increased from 4.66% to 4.67% kg/m3 compared to condition before modify. Before modify, the farm was managed in traditional way.

More research in the field of irrigation scheduling and providing comprehensive instructions to farmers in different weather conditions and different irrigation systems, taking into account different management approaches in allocating water to different parts of the farm along with investigating the effects of saline water irrigation, can be topics for the next research should be for experts in this field.

The present experiment was conducted to investigate the effect of tillage, organic fertilizers and mycorrhiza on quantitative traits and nutrient uptake in maize. The experiment was performed as a split plot with 4 replications in a randomized complete block design in August of the crop year 2017 and 2018 in Ivan city in Ilam province. Tillage at 3 levels (no tillage, tillage to a depth of 10 cm and tillage to a depth of 30 cm), organic fertilizer at 3 levels (no use, vermicompost 30 tons per hectare and bovine manure 30 tons per hectare) and mycorrhizal fungus Glomus mosseae and it was by soil inoculation method (consumption and non-consumption). In a minimal tillage system, seed yield was 7053.2 kg ha-1, an increase of 21% compared to the least amount of tillage-free treatment. In the minimum tillage system and the consumption of cow manure, the highest grain yield was obtained in the amount of 8198.2 kg ha-1. The interaction of mycorrhizae and tillage on grain yield was significant. In the case of minimal tillage and mycorrhizae, the maximum grain yield was707.1 kg ha-1, which was significantly different from the treatment without tillage and deep in both mycorrhizal and non-amycorrhizal states. According to the results obtained in this study, it was found that soil application at least relative to the deep system has increased plant yield.

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.

Water and nitrogen are known as the two main limiting factors in achieving maximum yield in agriculture. Therefore, the use of nitrogen fertilizer plays a significant role in increasing agricultural production. However, the indiscriminate use of these fertilizers may be due to their low efficiency. Therefore, investigating the challenges of water scarcity and improper nitrogen use management is crucial. In this study, considering the challenges of water scarcity and improper nitrogen use management, an investigation has been conducted.

This experiment was conducted in the research farm of the Agriculture Faculty of Shirvan Azad University during the agricultural year of 1399-1400. The experiment was carried out in the form of strip plots in three replicates and in a complete randomized block design. Three levels of 50%, 75%, and 100% of plant water requirement were considered as the main plot and five levels of zero (N0), 100 (N100), 200 (N200), 300 (N300), and 400 (N400) kilograms of nitrogen per hectare were considered in the subplots.

Most attributes related to yield components had higher values during the second year in comparison with the first year of the experiment. Moreover, plant height, grain weight, rows per cob and kernels per row in the 100% water requirement were greater compared with the 50% water requirement treatment. As a result of 400 kg/ha nitrogen fertilizer application, plant height, rows per cob, kernels per row, 100-grain weight and biological yield increased by 24.4%, 24.6%, 23.8%, 24% and 24.2% compared with the nitrogen-free treatment, respectively.

Increasing nitrogen fertilizer application leads to an improvement in yield and yield components. The only factor that decreased with increased water supply was water use efficiency. Grain yield under 100% water requirement was 38% more than that of 50% water requirement treatment. The difference between 100% and 50% water requirement treatments in terms of the biological yield was 49.5% in the first and 24% in the second year. Also, increased nitrogen fertilizer application led to increased grain yield. However, no significant difference was observed between 300 and 400 kg/ha nitrogen fertilizer treatments, especially in the second year. Therefore, a 300 kg/ha fertilizer application is recommended to achieve a suitable yield. Fertilizer use efficiency was affected by water requirement so that nitrogen use efficiency under 100% water requirement supply at a given nitrogen fertilizer level (e.g. 100 kg/ha) was significantly higher than that of 50% water requirement conditions. Under 100 kg/ha nitrogen application, nitrogen use efficiency in 100% water requirement treatment was 111.5 and in 50% water requirement treatment was 74.3 kg/ha. Thus, nitrogen use efficiency declined by 33% due to decreased water use. Therefore, it can be concluded that in conditions where sufficient water is not available for irrigation, farmers should not use excessive amounts of nitrogen fertilizer because it has little efficiency and only leads to environmental pollution and capital waste.

Considering the questions about the reasons for the decline in the quality of corn seeds in Moghan, especially regarding the management of corn cob dryers, this experiment was conducted in order to diagnose the effect of the dryer function on seed quality. For this purpose, 24 samples of corn seed variety 704 were prepared in two stages from nine seed processing stations in 2018. 12 cobs from the shipment were transported from the field and before entering the dryer and 12 dried cobs of the same shipment were randomly registered and tested in the National Seed Quality Laboratory. In addition to laboratory tests, each sample was cultivated in the field in the form of a RCBD in three replications. According to the results there is no significant difference between the sampling time before and after drying. The interaction of processing station and sampling time, except in two stations, did not show any significant difference on seed quality indicators. Based on the results, in the stations with higher output seed quality, the cobs were harvested with a moisture content of 25-29% and aerated at a temperature of 32-35℃ and after reaching the average moisture content of the mass about 20%, the temperature increased to 38℃. According to the results, the dryers function has a minor role in causing damage to seeds and reducing seed quality, and due to the low germination power of seeds produced in farms, other factors including farm management are effective in reducing the quality of corn seeds.

In order to investigate the use of biological and chemical nitrogen fertilizers in the conditions of limited water resources, a research was conducted in Arak during the crop years of 2016 and 2017 on the content of nutrients stored in the dry fodder of Maxima hybrid corn. This experiment was done in the form of a split-split plot and in the form of a basic design of randomized complete blocks in four replications, so that the irrigation levels were placed in the main plot and the nitroxin and nitrogen levels were placed in the sub-plots. The investigated treatments were irrigation at two common irrigation levels and applying water restriction, nitroxin at three levels of the control treatment, consumption of 0.5 and one liter of nitroxin per 30 kg of seeds consumed and nitrogen at three levels including the control treatment, consumption of 125 and 250 kg of nitrogen per hectare provided through 46% urea fertilizer. It was concluded that the effect of the year on the amount of nitrogen, protein and raw ash of fodder was significant and in the second year of testing the mentioned traits increased. The effect of irrigation factor on the yield of dry fodder, the amount of phosphorus and raw ash of fodder was significant, and the aforementioned traits increased under favorable irrigation conditions. Nitroxin treatment also showed a significant effect on experimental traits and with increasing the amount of nitroxin consumption, experimental traits often increased. The mutual effect of irrigation and nitroxin on all the measured traits was significant, and with the application of one liter of nitroxin under common irrigation conditions, the highest amount of these traits was obtained. In the conditions of applying irrigation restrictions, the use of 1 liter of nitroxin compared to the use of 0.5 liters and also the treatment without the use of nitroxin resulted in an increase in traits. The mutual effect of irrigation and nitrogen on all studied traits was significant except for dry fodder yield, so that the highest amount of these traits was obtained from the consumption of 250 kg of nitrogen under conventional irrigation conditions. The interaction effect of nitroxin and nitrogen on experimental traits was significant, so that the highest average of them was obtained by consuming one liter of nitroxin together with 125 kg of nitrogen. The interaction effect of all three treatments on all desired traits was significant, and in this regard, the highest amount of experimental traits was obtained as a result of consuming one liter of nitroxin with 125 kg of nitrogen under favorable irrigation conditions.

For investigation the effect of zeolite on vegetative characteristics and yield components of some maize cultivars under drought stress conditions (60% of field capacity), this experiment was performed in factorial based on randomized complete block design during 2017-2019. Factors studied in this experiment included 4 levels of zeolite (zero, 5, 10 and 15 tons per hectare) and four maize cultivars (Simon, hybrid BC678, KSC703 and KSC704). Based on the results, in drought stress condition, height and fresh and dry weight of plants was reduced. Application of zeolite moderated the effect of drought stress, so that application of 10 and 15 tons per hectare of zeolite improved morphological (plant height and fresh and dry weight of plant), physiological (water use efficiency and chlorophyll content), yield and yield components (Number of seed rows per ear, number of seeds per ear, 1000-seed weight and grain yield) and biochemical traits (soluble carbohydrates, proline, protein, total phenol and peroxidase activity characteristics). Based on the results, application of zeolite under drought stress conditions intensified the increase of soluble carbohydrates, proline, protein, total phenol and peroxidase activity in plant tissues and thus modulated the effect of drought stress on morphological and yield traits. In general, use of 10 and 15 tons per hectare of zeolite were the most suitable values to moderate the effect of drought stress in the studied maize cultivars. Also, among the studied cultivars of maize, Simon cultivar showed a better response to the application of zeolite under drought stress than other cultivars and was superior to other cultivars in terms of all studied traits.

In order to study the adaptability and determine the cultivation value of new corn hybrids, 16 forage maize genotypes of local and exotic origin were evaluated along with three common genotypes (KSC704, Bolson and Massil) in four different regions (Karaj, Maghan, Jovein and Dezful) using randomized complete block design with four replications in two years (2020 and 2021). Important traits such as days to flowering, plant height, ear height, ear-to-plant ratio and wet silage yield were recorded, based on the manual of value for cultivation and use test. To evaluate the yield stability, Francis and Kannenberg's environmental coefficient of variation was used. The results of two-years mean comparison of yield showed that Egean, Sy-Lavaredo, ZP873, Zarin2 and Zarin3 hybrids had the highest forage yield with 65.4, 64.8, 64.7, 63.8 and 62.3 tons per hectare, respectively, While the average yield of check varieties was 60 tons per hectare. Sy-Andromeda, Sy-Lavaredo, Egean, Jeta poly, Zarin 1, Zarin 2, Zarin 3 and ZP873 hybrids can be introduced with general adaptability, due to their higher yield and yield stability in comparison with the check varieties. Sy-Bilbao and BT-6470 hybrids are recommended in Karaj and Jovein regions and Ajeeb and ZP600 hybrids are also recommended in Jovein region with specific adaptability. ZP707, RGT-Joxxlin, RGT-Coruxxo and Exxupery hybrids do not deserve to release as a new variety because of low forage yield and yield adaptability in comparison with the check varieties.

The present research was conducted in order to investigate the effective factors on reducing the effects of drought in corn cultivation and to provide extensional-educational solutions in Azadi village (of Andimshek county). The statistical population was formed by all the corn growers of Azadi district in the crop year of 2021-2022, which were equal to 600 people. The sampling method was random and the samples were selected from among the people of the society in a simple random manner. To determine the sample size due to the limited statistical population, the Karjesi-Morgan formula was used, and according to the Karjesi-Morgan table, 237 people were selected. The data collection tool is a researcher-made questionnaire Data analysis using software SPSS Ver. 26 was done. The results of the T test showed that there is a significant difference at the level of 95% between farmers' knowledge and awareness (technical knowledge), human factors, management factors, economic factors, extensional-educational strategies and farmers' attitude towards reducing damage caused by drought with mean average of the population. They can minimize the damage caused by drought. Based on the structural model (PLS), the technical knowledge of corn farmers, management factors and educational-promotional strategies had the greatest effect on reducing the damage caused by drought, so that the value of the path coefficient for them was equal to 0.378, 0.359 and 314. Also, the path coefficient of human factors and economic factors were equal to 0.142 and 0.129, respectively, which had less effect on reducing the effects of drought.

The first step in breeding programs is to use the genetic diversity among existing populations, cultivars and lines. Maize is used as a model plant to study the genetics of various traits. Compared to other crops, maize has a high demand for zinc (Zn) and is known as an indicator of zinc deficiency in the soil. In terms of climatic conditions, Iran is located in a arid and semi-arid region, and there is a lack of micronutrients specially Zn in this region. Lack of nutrients such as Zn is one of the important abiotic stresses that affects the growth and development of plants including maize. The objective of this study was to evaluate the genetic diversity of a number of corn lines under normal and zinc deficiency conditions.

To assess the genetic diversity of 95 maize lines using agro-morphological traits, an experiment was carried out in alpha lattice design in two replications under two normal (use of zinc sulfate fertilizer) and zinc deficiency (no use of zinc sulfate fertilizer) conditions in Zabol Agricultural Research Center during two years. The studied maize lines were obtained from Razi University of Kermanshah, Khorasan Razavi Agricultural and Natural Resources Research Center, and Seed and Plant Improvement Institute (SPII) in the form of research project No. 94/101/T.T. approved by Biotechnology Institute of Urmia University. Twenty-nine traits were measured and recorded. Combined analysis of variance of the studied traits under normal and zinc (Zn) deficiency conditions were performed using SAS ver. 9.4 software. Other statistical analyzes including descriptive statistics, Pearson correlation coefficient, forward stepwise regression and factor analysis method were done using R software by pastecs, corrplot, olsrr, and psych packages, respectively.

The results of this study revealed high phenotypic variation among the studied maize lines for all investigated traits under both normal and zinc (Zn) deficiency stress conditions. The results of analysis of variance confirmed the presence of high phenotypic diversity among maize lines. All traits were affected by environment, and a statistically significant difference was observed between two environments for the all measured traits in maize lines. Genotype × environment interaction was also significant for most of the studied traits. Descriptive statistics showed a considerable diversity among the lines, and the highest diversity in both normal and zinc deficiency conditions was observed for yield per unit area, economic yield, and number of grains per cob. In correlation analysis, weight of five cobs, number of grains per cob, and 100-grain weight showed a positive and significant correlation with economic yield in both normal and zinc deficiency conditions. Therefore, these three can be introduced as important traits in the initial selection of zinc deficiency tolerant lines. In factor analysis of morphological traits using the parallel analysis method, four hidden and independent factors were determined under both normal and zinc deficiency conditions, which explained 63% and 57% of the total variation of the lines, respectively. Based on the results of the factor analysis, the traits number of days to tasseling, number of days to pollen emergence, number of days to cob emergence, plant height, ear diameter and width, number of grains per cob, economic yield, yield per unit area, and harvest index with high degree of commonality under both normal and zinc deficiency conditions, can be suggested as key traits for the selection of zinc deficiency tolerant lines.

The results of this research showed that there is a high genetic diversity among the studied maize lines in terms of morphological traits under both normal and zinc deficiency stress conditions. It makes it possible to use these lines in breeding programs as a valuable genic source to improve the performance of lines and produce improved lines under normal and zinc deficiency conditions.

In this study, the effect of the effluent from rainbow trout ponds was investigated on the yield, concentration and uptake of nitrogen, phosphorus and micronutrients on the silage corn in the Golpayegan research station for Husbandry and Agriculture in Isfahan. 45000 fish with an average weight of 10 ± 2 g were uniformly divided in 9 ponds (20 × 2.2 × 1.3 m) for six months. The research was conducted in a complete randomized block design with five treatments in triplicate. The treatments were included 1) irrigation with well water without any fertilizer as the control, 2) irrigation with well water and use of urea, triple superphosphate and potassium sulfate as the fertilizers, 3) irrigation with fish ponds effluents without any fertilizer, 4) irrigation with fish ponds effluents and use of the fertilizer, and 5) irrigation with fish ponds effluents with 50 percent of the fertilizer. Results showed that the use of fish ponds effluents significantly caused increasing in corn yield and concentration of zinc, cupper, nitrogen, phosphorus, manganese and iron (p<0.05). In addition, using fish ponds effluents with the 50% of chemical fertilizer led to increase corn yield by 44 percent compared to the control group (p<0.05). Moreover, the uptake of iron, zinc, copper and manganese by corn were increased significantly compared to the control group through use of fish ponds effluents water with fertilizer (p<0.05). The highest and lowest yield of corn was obtained in the irrigation with the effluent of fish ponds effluents coupled with chemical fertilizers and the control group, equal to 73.7 and 44.4 tons per hectare, respectively, which had significant difference with each other (p<0.05). Therefore, the use of fish farm effluents for production of corn not only increased the yield but also dramatically enhanced fertilizer utilization.

In Iran, pressurized irrigation systems cover a large area of agricultural land, but water use efficiency remains low because farmers tend to do deficit (over) - irrigation due to their lack of knowledge of crop water requirements. To address this issue, irrigation systems can be automated, and it is important to estimate crop water requirements accurately. This can be done based on soil moisture deficit or meteorological data. The water required can then be applied using a volume meter or by determining irrigation time based on the sprinkler flow rate. The study aimed to compare crop water requirement estimates based on soil moisture deficit and meteorological data, as well as the amount of water applied using volume and time-based methods.The study was conducted in the research farm of Razi University, Kermanshah, Iran, on a sprinkler irrigation system equipped with pressure and flow measuring devices, pressure switches, and electrical valves. The field was under corn cultivation, and four types of irrigation management were evaluated, which included a combination of two methods of determining crop water requirement (soil moisture deficiency and meteorological data) and two methods of irrigation application (time or volume). The four treatments were soil moisture - time (MT), soil moisture - volume (MV), weather - time (WT), and weather - volume (WV). The crop water requirement was calculated using the Penman-Monteith formula based on daily weather data. Soil moisture was measured at different depths one day before irrigation, and the soil moisture deficit was calculated to determine the crop water requirement based on soil moisture. The irrigation volume for each sprinkler in the irrigation cycle was calculated using equations that written in the paper.In the volumetric-based method (treatments WV and MV), the volume of water applied was measured using a water meter with a precision of 0.1 liters, and irrigation was stopped after passing the required volume of water. In the time-based method (treatments WT and MT), the irrigation time was calculated by dividing the irrigation volume by the average flow rate of the sprinklers (3 liters per second), and irrigation was stopped after the calculated duration. The actual sprinkler flow rate was calculated based on the volume of applied water and irrigation time in each treatment and irrigation round. Crop yield was measured at the time of harvest in the studied treatments and a control treatment managed by the Faculty of Agriculture. The irrigation treatments were not applied in the first month of the growth period due to field limitations.The results show that the crop water requirement calculated based on meteorological data at the beginning and end of the growing period was more than the method based on soil moisture. In total, the amount of crop water requirement calculated based on soil moisture was 8% more than the meteorological-based method. The volume of applied water in treatments of MT and WT was 14 and 8% more than in MV and WV treatments, respectively.The actual flow rate of sprinklers was different from the design flow rate due to irrigation situations in other parts of the farm. The average discharge of sprinklers (12 irrigation events) in WT, MT, WV, and MV treatments was 2.79, 3.03, 3.27, and 3.12 l/s, respectively. The irrigation time in volume and time-based methods also showed a significant difference. The irrigation time in MT and MV treatments was 10 and 18% longer than in WT and WV treatments, respectively. The study found that due to the non-uniformity of sprinkler discharge, applying irrigation by volume method is better than the time-based method. The results suggest that the MV treatment, which determined the amount of irrigation based on soil moisture deficit and applied it using a volumetric method, is a suitable option for automating sprinkler irrigation systems in the studied region.

To evaluate the effect of row spacing, planting pattern and density on weed control and morpho physiological characteristics of corn (Zea may L.), the experimental was carried out factorial based on a randomized complete block design with three replications in the farm of Moghan Agriculture and Natural Resources Research Station in 2022. The first factor included row spacing in two levels (75 and 65 cm), the second factor was planting pattern in two levels (single row and zigzag twin row) and the third factor was planting density in two levels (75,000 and 85,000 plants per hectare). The results showed that the highest grain yield and leaf area belonged to the density of 75000 plants per hectare and the row spacing of 75 cm. The highest density and total biomass of weed was observed at density of 75,000 plants per hectare and row spacing of 75 cm, But the lowest density and total biomass of weed was obtained from the density of 85,000 plants per hectare and row spacing of 65 cm. The maximum cob diameter, cob wood diameter and leaf chlorophyll index were obtained at the density of 75,000 plants per hectare with the row spacing of 75 cm and the single row planting pattern. Correlation coefficients between traits showed that the correlation between grain yield with total weed biomass, cob diameter, cob wood diameter, seed depth and leaf chlorophyll index is positive and significant. Generally, the results of this research showed that with extending of twin row patterns with increased density of corn, it is possible to control weed through the competitive ability of the plant, it achieved an acceptable performance.