نشریه پژوهشهای زراعی ایران
سال بیستم شماره 4 (پیاپی 68، زمستان 1401)

Maize (Zea mays L.) is one of the most important cereals after wheat and rice in the tropical and temperate regions of the world. Also, its mean production is 8 ton ha-1. Moreover, the total area of under cultivation is 132572 hectares in Iran. Crop simulation models can play an important role in improving agricultural production systems in many developing countries. Crop models can simulate plant growth processes and grain yield instead of conducting several years of field experiments. On the other hands, crop simulation models should be calibrated and evaluated with independent data sets under different climatic conditions. Therefore, the purpose of this research was evaluation of the APSIM model for simulation of growth, development and yield of maize hybrids in Kerman province under different amounts of nitrogen.

The APSIM model was calibrated and validated using measured data from a two-year field experiment conducted in the 2014 and 2015 growing seasons. The experiment was a factorial arrangement based on a randomized complete block design (RCBD) with three replications conducted at Kerman province in Iran. Four nitrogen rates (0 (control), 92, 220 and 368 kg ha-1) and two maize hybrids (KSC 704 and Maxima) were included in the study. Moreover, inputs of APSIM model were climatic, soil, plant and management data. In order to calibrate the APSIM model, the data of field experiment in the first year (2014) (including flowering date, physiological maturity date, leaf area index, biological yield and grain yield) were included. Moreover, Data from the second experiment (2015) were used to validate the model.

Our results showed that APSIM model accurately predicted phenology (nRMSE=4.5%). But the APSIM model did not capture the effect of nitrogen stress on phenology. At the evaluation step, the model couldn’t accurately predict the maximum leaf area index (nRMSE=26 and 18% for SC 704 and Maxima hybrids, respectively) which led to overestimate of the results. The nRMSE values for the biological yield of SC 704 and Maxima hybrids were 13.9% and 5.7%, respectively. Furthermore, the values of Wilmot agreement index (d) for these SC 704 (0.95) and Maxima (0.99) indicated a close agreement between the field-measured and simulated values. Furthermore, the nRMSE for grain yield simulation of SC 704 and Maxima hybrids were 13.2 and 11.9 percentage, respectively, revealed that the model accurately simulated the grain yield of maize hybrids.

The evaluation of the APSIM model with the experimental data revealed that the model predicted grain yield, biological yield, days to flowering and maturity of maize hybrids reasonably well. This indicates that the model could be applied for assessing various management practices in maize agro-ecosystems under all parts of the semi-arid regions which has the similar characteristics to the study location. On the other hands, the APSIM model couldn’t predict the effect of different nitrogen levels on phenology.

Sugar beet (Beta vulgaris L.) is the second most important sugar crop after sugarcane, which annually produces about 40% of total sugar production worldwide and is adapted to different climatic conditions (El-Hag et al., 2015). Due to global warming, autumn cultivation of sugar beet is predicted to become more priority in the future, but autumn cultivation is in danger of bolting and flowering in many areas. Excessive bolting reduces sugar content, root yield, and purity of raw syrup. In general, both early sowing and delayed sowing reduce root yield, sugar, and leaf area index and increase the percentage of impurities. Therefore, this experiment was designed and implemented with the aim of feasibility study of autumn cultivation of sugar beet and determination of the best planting date in North, Razavi, and South Khorasan provinces for three new varieties resistant to sugar beet.

The experiment was conducted as a split-plot design based on a randomized complete block design with three replications in the provinces of North Khorasan (Shirvan), Khorasan Razavi (Mashhad), and South Khorasan  (Khezri Dasht-e Bayaz) in 2019-2020. The main plots included three planting dates (2, 7, and 12 October) and the subplots included three bolt-resistant sugar beet cultivars (Giada, Merak, and Sharif). Each plot consisted of 6 rows with a length of 5 m, at a distance of 50 cm and a distance between two plants of 20 cm, and planting was done manually. To determine root yield from the middle rows of each plot by eliminating the margin, harvest was done at an area of 4 m2. A sample of root paste of each treatment was sent to the Beta Lizer laboratory of Mashhad Agricultural Research and Agricultural Services Company to determine the percentage of sugar. Other quality parameters were measured by Beta Lizer (Braunschweig method). Using the polarimetry method (Sucromat), the percentage of sugar content and white sugar yield, and other quality parameters were calculated for all experimental plots. Combined analysis of variance for different locations and mean comparison based on least significant difference (LSD) at the level of 5% probability using SAS 9.4 software was performed. Also, the graph plots were performed using Excel software.

The results of the analysis of variance showed that the interaction effects of the location and cultivar were significant on bolting percentage, root yield, sugar content, Na content, yield coefficient, and white sugar yield. The first planting date (October 2) in Mashhad region for all three cultivars led to the highest percentage of bolting (78-90%). Delay in planting date from 2 October to 12 October, the bolting percentage of cultivars was reduced, significantly. The bolting percentage in Shirvan region was less than 8%. On the third planting date (October 12) in all regions, cultivars showed also a bolting percentage of less than 10%. Giada cultivar in Mashhad region with 47.3 ton.ha-1 had the highest and Sharif cultivar in Shirvan region with 22.6 ton.ha-1 had the lowest root yield. Shirvan region had less root yield than the other two regions. The highest sugar content (18.78%) belonged to Giada cultivar in Shirvan region and the lowest sugar content (13.01%) was observed in Sharif cultivar in Mashhad region. The planting date of 12 October was significantly lower in impurities, alkalinity coefficient, and molasses compared to earlier planting dates. The first planting date had the lowest (62.3%) and the third planting date had the highest (74.2%) extraction coefficient. Giada cultivar in Shirvan region had the highest extraction coefficient (78.1%) and the lowest extraction coefficient (60.8%) belonged to Sharif cultivar in Mashhad region.

In Shirvan and Khezri regions, Giada cultivar but in Mashhad region, Merak cultivars had the highest white sugar yield. In general, the results showed that in Shirvan region, planting on 2 October and in Mashhad and Khezri regions planting on 7 October could lead to reaching maximum white sugar yield.

There is an urgent need to increase per capita food production to compete with high population growth while maintaining environmental sustainability. Because nitrogen plays a vital role in food production for humans and livestock, nitrogen management is essential in food production. In most cropping systems, nitrogen management seems to be a major challenge due to its high mobility and natural tendency for losses from the soil-plant system to the environment. Soil organic carbon plays a key role in improving soil ecological conditions. Adding organic matter to the soil is an excellent tool for improving physical, chemical and biological conditions and is almost always desirable. Soil organic carbon stock of crop ecosystems may be increased by improving farming practices. The application of green manure, fertilizer and the return of crop straw into the soil are known as management operations to increase soil organic carbon. Fertilizers, especially nitrogen, increase crop yield, and organic carbon is returned to the soil through roots and debris, which in most cases leads to increased soil organic carbon.

This study was conducted with the aim of utilizing a set of improving farming practices in diverse cropping systems to improve nitrogen efficiency during two crop years. Farming practices including removal of summer fallow were used by importing three crops of mung bean, corn and wild rocket in rotation plus nitrogen supply levels factor. The crop rotation factor was applied in four levels of Fallow-wheat, mung bean-wheat, corn-wheat and wild rocket-wheat and the factor of nitrogen fertilizer (0, 180 and 360 kg.ha-1) in a randomized complete block design as factorial. Soil mineral nitrogen (nitrate and ammonium) were measured before sowing wheat and grain, straw and total plant nitrogen after harvest. Uptake efficiency, utilization efficiency, agronomic efficiency and nitrogen harvest index were calculated.

The results of combined analysis of variance showed that the crop rotation and nitrogen were significantly effective (ρ ≤ 0.01) on plant nitrogen, harvest index and nitrogen efficiency. Increasing nitrogen fertilizer up to 360 kg.ha-1 increased grain nitrogen, straw nitrogen, total plant nitrogen and also nitrogen harvest index. While the best uptake, utilization and agronomic efficiency of nitrogen was observed on the treatment without nitrogen fertilizer. Comparison of the means showed that the wild rocket-wheat crop rotation had the best result among all measured traits except utilization efficiency, while the utilization efficiency in the corn-wheat crop rotation showed the best performance. The results clearly show the effect of increasing organic carbon on nitrogen availability and grain nitrogen concentration as well as the role of cover crops and legume, in increasing access to nitrogen. The amount of grain nitrogen was directly affected by the amount of nitrogen fertilizer. The highest correlation coefficient was seen between agronomic and uptake efficiency (r = 0.96**). There was also a significant inverse relationship between nitrogen harvest index and the types of calculated efficiencies. The amount of uptake efficiency and agronomic efficiency in all crop rotations except corn-wheat in the second year improved compared to the first year. The highest increase in efficiency in the second year was related to the wild rocket-wheat crop rotation. In the conditions of 360 and 180 kg.ha-1 nitrogen fertilizer, the nitrogen harvest index increased in the second year compared to the first year. While in conditions without nitrogen fertilizer, nitrogen harvest index has a significant decrease. Therefore, at least in the short term, to increase the nitrogen harvest index, the minimum supply of nitrogen fertilizer should be used, even under improving crop management conditions such as green manure, removal of fallow and introduction of legumes in rotation and return of crop residues.

Continuous cropping, removal of fallow, use of cover crops and legume and preservation of residues led to increased carbon and nitrogen sequestration in soil and consequently increase biomass and nitrogen concentration in plant tissue. On the other hand, crop rotations that increased soil organic carbon and improved soil fertility quickly improved nitrogen efficiency and nitrogen harvest index.

During the 1950s and 1960s, the green revolution led to a dramatic increase in global food and fodder production to eliminate hunger and boost food security. This production enhancement was accompanied by an intensified agricultural and chemical input consumption and increased cultivated area and mechanization. Although yield per unit area has improved in most crops, concerns about food security for the world's rising population are still significant. Guaranteeing food security in the future will necessitate a shift in management approaches to boost output, agroecosystem sustainability, and stability and reduce the environmental harm caused by agriculture. The first step to achieving sustainability and ecological intensification in agricultural systems is to have a comprehensive agroecological analysis of agricultural systems in each region. Hence, the complete evaluation and analysis of agroecological features according to their type in each region is necessary for establishing an optimal management technique. After analyzing the present state of each region's shared ecosystems, the optimal strategy for boosting production stability must be devised and implemented.

The goal of this study was to undertake a detailed investigation of the agroecological state of the sugar beet ecosystems on a local scale. For this purpose, data were collected on the area under cultivation, yield, and input consumption (including nitrogen and phosphorus fertilizers and chemical pesticides) from 2001 to 2016. Data was acquired from the Ministry of Agriculture and other related organizations and direct interviews with the farmers. In addition, data on climatic parameters (including daily minimum and maximum temperatures, precipitation, and sunny hours) were collected from the Torbat-e Heydariyeh meteorological station. This study researched the most important agroecological indicators of sugar beet farming systems in the Torbat-e Heydarieh region. Study indicators include variations in sugar beet cultivation area and yield, Potential yield via the methods FAO and FAO modified, beet yield gap, Regional Yield Factor trend, Changes in the intensification, yield stability, nitrogen uptake, and nitrogen utilization, and nitrogen use efficiency.

According to this study results, sugar beet production increased by 59 percent between 2001 and 2016. During the research years, sugar beet ecosystems saw a drop in the cultivation area. Potential yield calculations using both FAO and modified FAO methodologies revealed that potential yield was nearly consistent over the research period in the region.The sugar beet yield gap averaged 35 ton.ha-1 over the research period. According to the findings, the percentage of sugar beet yield gap ranged from 53 to 69 %, with an average of 63 %. The extent of the yield gap decreased over the research period. The study of the regional yield factor (RYF) revealed that improving the management system resulted in higher actual yield and thus a smaller yield gap in sugar beet ecosystems. In sugar beet cultivation systems, the results revealed that by increasing intensification, the stability decreased. In sugar beet cultivation systems, there was a reduction in yield stability. Given that nitrogen consumption efficiency is one of the most important factors influencing the degree of stability in agricultural systems, the findings revealed that the rate of nitrogen uptake efficiency (NUpE), nitrogen utilization efficiency (NUtE), and nitrogen use efficiency (NUE) all decreased during the studied years in the region.

According to the findings, the major cause of the increase in nitrogen consumption, growing intensification, and decreasing stability in the analyzed systems appears to be a deficiency of nitrogen use efficiency and its downward trend. As a result, planning and altering management methods focusing on enhancing Nitrogen use efficiency may be proposed as the first step toward boosting sustainability in the Torbat-e Heydarieh sugar beet agroecosystems.

Grasspea (Lathyrus sativus L.) is one of the most important forage crops in the world. It contains 12 to 20% protein. Silicon (Si) existing in the Earth’s crust is classified as the most abundant element after oxygen. Although silicon is not considered an essential element for plant growth, but a number of studies have reported that it as an important factor in plants that plays an important role in the resistance mechanisms of plants against environmental stress. Also, it plays a crucial physiological role in photosynthetic rate and chlorophyll content. One of the most effective factors in increasing the Grasspea biomass is seed inoculation with plant growth-promoting rhizobacteria (PGPR). Some of the benefits provided by PGPR are the ability to produce gibberellic acid, cytokinins and ethylene, N2 fixation, solubilization of mineral phosphates and other nutrients. Numerous studies have shown a substantial increase in dry matter accumulation via inoculation with PGPR. Some researchers reported that seed inoculation with PGPR enhanced relative water content and photochemical efficiency of PSII lathyrus under water limitations. Therefore, the aim of this study was to evaluate the effects of nano silicon and seed inoculation with plant growth-promoting rhizobacteria on biomass, nodulation and some physiological traits of Grasspea.

In order to study the effect of nano silicon and plant growth-promoting rhizobacteria on biomass, nodulation and some physiological traits of Grasspea, a factorial experiment was conducted based on randomized complete block design with three replications in research farm of University of Mohaghegh Ardabili in 2021. Treatment were included application of plant growth-promoting rhizobacteria at four levels (no inoculation as control, seed inoculation with Azosprillum lipoferum strain OF, Psedomonas putida strain 186, both application of Azospirillium and Pseudomonas) and nano silicon foliar application at four levels (foliar application with water as control, foliar application 25, 50 and 75 mg.L-1 nano silicon). The area is located at 38° 15ʹ N latitude and 48° 20ʹ E longitude with an elevation of 1350 m above mean sea level. Climatically, the area is situated in the wet zone with cool winter and hot summer. For inoculation, seeds were coated with gum Arabic as an adhesive and rolled into the suspension of bacteria until uniformly coated. Seeds were inoculated with plant growth promoting rhizobacteria (PGPR) at the rate of approximately 1 × 107 colony forming units (CFU) mg-1 just before planting. Foliar application of nano silicon was conducted in two stages of vegetative growth. Nano silicon powder added to deionized water and was placed on ultra sonic equipment (100 W and 40 kHz) on a shaker for better solution. At the Flowering stage, the leaves of plants were selected to measure the stem and leaf protein, chlorophyll index, RWC (relative water content), quantum yield, stomatal conductance and EC (electrical conductivity). RWC was calculated based on method of Kostopoulou et al. (2010). Chlorophyll Index was calculated by chlorophyll meter (SPAD-502; Konica Minolta Sensing, Inc., Japan). The Quantum yield of leaves was calculated with fluorometer (chlorophyll fluorometer; Optic Science-OS-30 USA). Stomata conductance was measured with a porometer system (Porometer AP4, Delta-T Devices Ltd., Cambridge, UK) according to the instructions in its manual. Leaf electrical conductivity (EC) values were measured at room temperature of 23±1°C using an electrical-conductivity meter. Analysis of variance and mean comparisons were performed using SAS 9.1 computer software packages. The main effects and interactions were tested using the least significant difference (LSD) test at the 0.05 probability level.

The results showed that both application of Azospirillium and Pseudomonas and foliar application of 75 mg.L-1 nano silicon increased root weight and volume (40.4 and 41.9%), number of active nodules (81.2%), percentage of active nodules (33.2%), nodule dry weight (37.4%), chlorophyll index (46%), relative water content (46.3%), stomatal conductance (34.6%) and quantum yield (34.1%) in comparison with no application of PGPR and nano silicon. Also, the highest leaf and stem protein (23.37 and 12.66%) and total biomass (37.7 %) were obtained in both application of Azospirillium and Pseudomonas and foliar application of 75 mg.L-1 nano silicon in comparison with no application of PGPR and nano silicon.

It seems that application of PGPR and foliar application of nano silicon can increase biomass of Lathyrus sativus due to nodulation and  improving  physiological traits.

Wheat (Triticum aestivum L.) is one of the most important crops in the world as well as in Iran. It has experienced many improvements in terms of yield and quality traits during recent decades. Wheat, like energy, is known as a strategic commodity and is one of the important indicators of agriculture. This plant has the highest area under cultivation and production among other cereals in the world. Planting date is an important factor in crop production because meteorological parameters vary with changes in planting date. Delay in planting is one of the problems that is common in almost all wheat growing areas of Iran and is one of the main causes of reduced yields of wheat cultivars. Yield reduction rate varies depending on the delay in planting and cultivars, and the results of some experiments indicate that this amount sometimes reaches more than 35% of potential grain yield. Phenology and growth rate due to their effect on duration and the occurrence of different stages of development and the environmental conditions prevailing in each of these stages, are the key point of adaptation to various environmental conditions such as delayed planting date. This experiment was designed to identify the changes in yield and yield components and phenological stages of new bread wheat cultivars with different growth habits and to investigate the possibility of introducing cultivars compatible with delayed planting date in the region.

This research was conducted in two separate experiments based on a complete randomized block design with optimum planting date (6th November) and delayed planting date (6th December) on 10 new bread wheat cultivars with three replications on the research farm of the Seed and Plant Improvement Research Institute in Karaj in two years (2016-2018). The bread wheat cultivars include Pishgam, Heidari, Rakhshan, Sivand, Baharan, Sirvan, Parsi, Mehregan, Chamran 2 and Chamran. Yield and yield components such as number spike per m2, number of grain per spike, 1000-grain weight were measured at the end of the growing season to evaluate responses of the cultivars to the various planting dates. In addition, the phenological stage was recorded during the growing season.

Results indicated that delayed planting date from 15th Nov. to 15th Dec. caused a significant reduction on grain yield (from 7485 to 6066 kg.ha-1), number of spikes per m2 (from 698 to 605), number of grain per spike (from 28.5 to 25.8 seed), and 1000 grain weight (from 41.1 to 38.4 g). The interaction effects of planting date and cultivars were significant on grain yield and yield components. The highest and lowest grain yield belonged to Pishgam (7436 kg. ha-1) on optimum planting date and Chamran (5842 kg.ha-1) on delayed planting date, respectively. Delayed planting date reduced duration of planting to double ridge (from 736 to 641 GDD), planting to terminal spikelet (from 982 to 886 GDD), planting to anthesis (from 1608 to 1457 GDD) and planting to maturity (from 2456 to 2265 GDD).

Duration of different developmental stage is very important for the formation of yield components that determine the final grain yield. Although these stages are a genetic trait, but they are affected by plant growth conditions and environmental stresses, climatic factors, especially temperature and day length. Our research showed that delay in planting reduced grain yield by 18% compared to the optimum planting date because of the reduced number of spikes per m2 and vegetative and grain-filling periods.Based on the results, in cases of delayed planting date (unfavorable weather conditions, insufficient planting equipment, etc.) in Karaj region or similar climatic regions, early maturity cultivars such as Mehregan and Chamran 2 and moderate maturity cultivar like Sivand are recommended in order to minimize yield loss.

Water is now the main limiting factor for crop production in arid and semi-arid regions. Water-cut or irrigation interruption has been suggested as one of the main strategies agro-technique to get the most benefit from limited water resource available. In this regard, plant growth stage, time of stress induction and the genotype are the main key factors to determine the degree of success. Canola is one of the most important oil crop. It can survive some degree of water stress while there is a need for research to find the most appropriate genotypes for plantations in water-limited areas.

In order to determine the effect of water stress at the various growing stages of canola genotypes a split-plot experiment was conducted based on the randomized complete block design with three replications at the research farm of the department of plant production and genetics, Agricultural Sciences and Natural Resources University of Khuzestan, Iran during 2020-2021. Main plots included three irrigation treatments: control (without interruption of irrigation), interruption of irrigation in the beginning of the flowering stage (phenology code 60) to the formation of 50% pods (phenology code 75), and interruption of irrigation in the stage of formation of pods until harvest (Phenology code 99) in the main plots and the cultivars (Long pod, Aram, RGS 003, Jankom, Solar, Hayola 4815, Mahtab, Julius, Agamax and Sala) were arranged in sub-plots with respect to irrigation treatments. At the end of the growing season, plant height, number of branches, silique length, number of pods per plant, number of seeds per pod, 1000 grain weight, and grain oil percentage were measured. Also, after removing the marginal effect, economic performance, biological performance and harvest index were measured.

Our results revealed there was a significant interaction effect between irrigation interruption stress and genotype on all studied traits. The number of sub-branch among cultivars varies as a result of Irrigation interruption stress. The genotypes of the long pod and Hayola 4815 had the highest number of branches compared to other genotypes when irrigation was interrupted at the flowering stage up to 50%, while when applied stress at the stage of flowering up to harvest, genotype, solar exhibited the highest number of sub-branch. The lowest number of sub-branches in all interruption of irrigation and control treatments was obtained by Jankom genotype. The mean comparisons in the conditions without irrigation interruption (control) the highest percentage of seed oil was obtained from Solar (48.3%), Hayola 4815 and 4815 (46.3%), stress application in flowering stage up to 50% sowing of a long pod (45%) and Hayola 4815 (43%) genotypes in the sowing stress to harvest the highest percentage of seed oil from Sala and Long pod genotypes with average (44.3%) the lowest percentage of seed oil in all present treatments belonged to Jankom genotype. In the present study, the highest (2093.8 kg.ha-1) and the lowest (540 kg.ha-1) grain yield and the highest (986.51 kg.ha-1) and the lowest (191.21 kg.ha-1) grain oil yield in both conditions without irrigation interruption (control) and terminal drought stress were obtained from Hayola 4815 and Jankom genotypes, respectively.

The highest and the lowest grain yield, seed oil and biological yield were obtained from Hayola 4815 and Jankom, respectively. According to the results, Hayola 4815, long pod and Solar are highly recommended to cultivate in the regions where there is terminal water stress at the end of the growing season.

Intensive agriculture, despite high production, has adverse environmental effects, mainly due to the use of pesticides and chemical fertilizers. Therefore, we need alternative agricultural systems that are more economically and environmentally sustainable to produce crops. One of the sustainable methods in the production of agricultural products is intercropping. Intercropping of two or more species in a plot of land can increase biodiversity and resource utilization as agricultural perspective, which in turn can lead to increased yield stability. Intercropping uses resources more efficiently than monoculture, preventing the growth and spread of weeds by shading and suffocating weeds, and in some cases with allelopathic. Intercropping of cereals and legumes is recommended for the development of sustainable food production systems, especially in planting systems based on reduced consumption of foreign inputs. The importance of these systems depends on the nitrogen stabilized by the legumes. The aim of this experiment was to study the effects of row intercropping of barley and vetch and different levels of ammonium nitrate fertilizer on weed biomass, yield components and yield of two species in Karaj climatic condition.

This experiment was performed as a factorial split plot based on randomized complete block design in 2019-2020 cropping year in the research farm of the Agriculture and Natural Resources, University of Tehran. Main plots included three levels of ammonium nitrate fertilizer (0, 35 and 70 kg.ha-1) and sub-plots include different ratios of barley and vetch (100% barley, 80% barley: 20% vetch, 80% barley: 45% vetch, 80% barley: 70% vetch, 100% vetch, 80% vetch: 20% barley, 80% vetch: 45% barley, 80% vetch: 70% barley) weeding and non-weeding were in three replications. Plant density in sole barley and vetch were 250 plants per square meter. The method of cultivation in this study was additive intercropping. Seeds were sown on November 6th. The first stage of fertilization was done simultaneously with planting and one third was added to each plot and the second and third stages of fertilization were performed in two stages of stem emergence and spike emergence, respectively from ammonium nitrate fertilizer source. The final harvest was done on July 28th. Data were analyzed using SAS 9.1 software. The least significant difference test (P≤0.05) was used to compare the means.

The highest barley grain yield (432.44 g) was related to sole barley, 70 kg ammonium nitrate and weed control, which was not significantly different with 80% B: 45%V, 70 kg ammonium nitrate and weed control. Also, the highest yield of vetch grain (161.47 g) was obtained in sole vetch, application of 70 kg ammonium nitrate and weed control treatment, which was not significantly different with 80%V: 20%B intercropping, application of 70 kg ammonium nitrate and weed control treatment. Weeds in this experiment include: Wild oats (Avena fatua), ryegrass (Lolium temulentum), Bromus (Bromus tectorum), Fox tail (Alopecurus myosuroides), Wild mustard (Sinapis arvensis), Creeping Thistle (Cirsium arvense), London rocket (Sisymbrium irio), Cockspur grass (Echinochloa crus-galli) and Cornflower (Centaurea cyanus). The highest dry weight of weed (231.62 g) was observed in sole vetch, application of 70 kg.ha-1 ammonium nitrate fertilizer treatment. The highest land equivalent ratio LER (1.68) is related to 80% V: 70%B, non-application of ammonium nitrate fertilizer in weed control condition. Intercropping was successful in controlling weeds and using resources, thereby increasing the yield of plants in the experiment.

The results obtained from the experiment showed that all different systems of barley and vetch intercropping had land equivalent ratio higher than one, which indicates the superiority of intercropping over pure crops in the land use and crop production. Intercropping treatments were also able to control weeds. Intercropping with high ability to suppress weeds were able to use more resources. On the other hand, vetch biologically stabilized nitrogen was able to reduce the need for fertilizer in plants.