نشریه بوم شناسی کشاورزی
سال پانزدهم شماره 1 (بهار 1402)

Global warming has already been occurring in Iran and will probably continue during the 21st century. There has been an increased intensity and frequency of hot daytime temperatures in the last two decades in the country. Winter wheat (Triticum aestivum L.) is the most important staple food crop in the country, with a total farming area of nearly 6.33 million ha and a production exceeding 14 million tons in 2017. Wheat production in Iran is an important component of national food security. The crop is grown almost all over the country under varied soil and climatic conditions. Most parts of Iran have an arid and semi-arid climate with long dry summer and winter rainfall, which climate change may negatively affect wheat production sustainability in these vulnerable environments. Wheat is a thermo-sensitive crop, and a change in air temperature may alter the length of its growing period and grain yield. Wheat production mainly depends on the duration of the reproductive period; thus, precise crop phenology estimation is essential for yield prediction under current and future climate conditions. The variety of C-84-8, which is named "Mihan," was introduced from the cross between the domestic variety “Barkat” and the Chinese variety “Zhong87-90” in Karaj for normal irrigation conditions and drought stress after the flowering stage in the cold regions of Iran in 2009. Mihan variety is known as a high yielded potential. The actual yield of this variety in Ardabil province has been reported between 8.13 to 10.31 tons per hectare.

The aim of this study was to simulate the climate change effects on the growth period, LAI, and biological and grain yield of wheat (Mihan variety) in the Kerman and Ardebil regions. For this purpose, we employed the HadGEM2-ES model as affected by two RCP4.5 and RCP8.5 scenarios for two time periods, 2021-2055 and 2056-2090. MarkSIMGCMmodel was used to produce daily climatic parameters as one stochastic growing season for each projection period, and the CERES-wheat model in DSSAT software was used to simulate wheat growth. Calibration and validation of the model in Kerman were performed with two-year experiments designed at the Shahid Bahonar University farm in Kerman, and for the Ardabil region, it performed with the data of the wheat projects of the Agricultural Research and Training Center and Natural Resources of Ardabil province.

The results of the model evaluation showed that MarkSIMGCM had an appropriate prediction for simulating climatic parameters and stochastic growing seasons in future climate change conditions. In both studied regions, the RCP8.5 scenario has a higher temperature and radiation increase than the RCP4.5 scenario, and these changes are greater in the long-term period than in the short-term period. Rainfall changes in both investigated regions did not show a regular trend. The growing period length was reduced by 0.51% -4.59% as affected by various climate change scenarios and periods. In the near period time (2055), simulating results showed that wheat grain yield would decrease by 3.87% compared to the current condition based on the RCP4.5 scenario. But, the traits will be increased by 0.99%-15.15% according to the RCP8.5 scenario in Kerman and Ardebil based on both scenarios. In the far period time (2090), the grain yield for the Kerman region will respectively decrease by -7.39% and -36% according to both RCP4.5 and RCP8.5 scenarios compared to the current time, and in Ardabil, based on the scenario RCP4.5 will be improved by 20.36%, and it will be declined by -2.89% according to the RCP8.5 scenario. This indicates that the negative impacts of warming will outweigh to the positive effect of CO2 enrichment over time.

In general, the results confirmed that the Mihan variety would produce acceptable grain yield in the future climate change conditions of Ardabil, but in Kerman, mitigating strategies should be considered to adapt wheat to the adverse impacts of climate change.

For centuries, medicinal, functional, and nutraceutical herbs have been used for food and medicinal purposes. Lallemantia species are versatile and can be used for lightening, varnish, painting, food, and medicine. The genus is distributed in several countries, including Afghanistan, Pakistan, India, China, Syria, Iraq, Turkmenistan, Tajikistan, Kyrgyzstan, Kazakhstan, Uzbekistan, Russia, and some European countries. Lallemantia iberica belongs to the Labiatae family, which has about 220 genera and almost 4000 species worldwide, with 46 genera and 410 species and subspecies in Iran. Dragon’s head seed is a good source of polysaccharides, fiber, oil, and protein, with medicinal, nutritional, and human health properties. Its high mucilage content allows it to absorb water quickly, producing a sticky, turbid, and tasteless liquid, which can be used as a novel food hydrocolloid in food formulations. Given the increasing consumption and high economic value of dragon’s head medicinal plants, research on planting factors of this plant is necessary. The aim of this study was to evaluate some traits, such as grain yield, oil yield, percentage, and mucilage yield of five dragon’s head medicinal plant accessions.

The experiment was carried out in the research farm of Lorestan Agricultural and Natural Resources Research and Training Center in the 2018 crop year. The research farm's geographical coordinates are longitude 48°35′N and latitude 33°48′E, elevation above sea level is 1147.8 meters, average rainfall is 525 mm, and average temperature is 14.13 °C. Khorramabad region has a subtropical climate with hot and dry summers and a temperate climate based on long-term statistics. The experiment was performed on a randomized complete block design with three replications, including five dragons’ head accessions (Takab, Kaleibar, Kurdistan, Nazarkahrizi, and Jolfa). Traits evaluated included grain yield, biochemical traits, and photosynthetic pigments. Data analysis was done using SAS 9.1 statistical program, and means were compared using Duncan's multiple range test at the 5% probability level.

Analysis of variance showed that grain yield, oil yield, mucilage yield, 1000-grain weight, biological yield, and harvest index were affected by mass. According to the comparison, the highest mean of grain yield, oil yield, biological yield, and mucilage yield were obtained in Kaleibar mass and ranked next in Takab mass. The lowest grain and oil yield were obtained in Julfa mass. In the dryland conditions of Khorramabad region, Kaleibar massif was superior to other masses in terms of the studied traits. Correlation analysis in rainfed conditions showed that grain yield had the highest correlation coefficient with oil yield, mucilage yield, and biological yield. Pearson correlation between the studied traits and grain yield showed a significant correlation between grain yield and oil yield, mucilage yield, biological yield, and harvest index. Grain yield also correlated significantly with oil content, mucilage percentage, 1000-grain weight, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids. The highest positive and significant correlation was observed between chlorophyll b content and total chlorophyll content.

The study found that mass had a significant effect on the evaluated traits.ConclusionThe study found that mass had a significant effect on the evaluated traits.  The highest grain mucilage yield, grain oil, biological yield and also grain yield were observed in Kaleibar mass and then in Takab mass. There was a significant difference with other dragon’s head accessions. The lowest grain yield, mucilage yield, grain oil yield and biological yield were also obtained in Julfa massif. According to the experimental findings, in dryland conditions of Khorramabad region, Kaleibar mass are suitable for cultivation first and then Takab mass and have acceptable yield and can be recommended for cultivation in similar conditions.

Iranian shallot, scientifically known as Allium hirtifolium, is an important medicinal, edible, and industrial plant that grows in different regions of Iran, especially in the Central Zagros. Since this plant is harvested from its natural environment for consumption, it is necessary to cultivate and study various factors that affect its quantitative and qualitative yield, such as the use of sustainable agriculture. Additionally, genetic and environmental factors, as well as the use of fertilizers and nutrients, affect the growth, development, and yield of medicinal and edible plants, including Iranian shallots. Therefore, creating the best substrate for cultivation, protection, and harvesting is necessary due to the use of these plants in human health. The purpose of this study was to investigate the effect of chemical and organic fertilizer in inoculation with biofertilizer in two years on the yield and biochemical traits of Iranian shallot.

In this study (in the research farm of Islamic Azad University of Shahrekord in Chaharmahal and Bakhtiari province) investigated the effect of chemical fertilizer application (including: nitrogen, potassium, phosphorus 90, 70 and 60 kg/ha, respectively), chemical fertilizer inoculation with fertilizer Vermicompost (10 tons per hectare), Vermicompost inoculation with bio-fertilizer, manure (including sheep manure 10 tons per hectare), manure inoculation with bio-fertilizer (Including Arbuscular Mycorrhizal Fungi including: Glomus fasiculatum, Glomus intraradices and Glomus mosseae and growth-promoting bacteria including: Azospirillum spp, Pseudomonas fluorescens and Bacillus subtilis) on Iranian shallot biochemical and yields traits such as: size and weight of Bulb, Amount of phenol, Flavonoid Antioxidants, Starch, Glucose, Total protein, Nitrogen, Phosphorus, Potassium of this plant, as an randomized complete blocks design with three replications in two consecutive years (2016-2017 and 2017-2018) was conducted and The simple(year and fertilizer) and combined analysis(year* fertilizer) of variance were done. Data analysis was performed using SAS9.1 software, and LSD test at 5% probability level was used to compare the mean of treatments.

The results of the variance analysis showed that the effect of year on all traits was significant, including size and weight of bulb, phenol, flavonoids, antioxidants, starch, glucose, total protein, nitrogen, and phosphorus, at the level of 1%. The effect of fertilizer on all traits (except starch and glucose) and their interactions (year x fertilizer) on all measured traits except antioxidant activity percent, nitrogen, starch, and glucose were also significant.In the second year, antioxidant activity percent, nitrogen, starch, and glucose had the highest amounts at 42.71%, 2.30%, 0.40, and 0.38, respectively, while in the first year, they had the lowest amounts at 29.05, 1.44, 0.23, and 0.23 mg/g fw, respectively.According to the results, the highest bulb size (8.04 cm), potassium (1.88% and 1.89%), bulb weight (0.095 and 0.096 kg), and total protein (15.05 and 15.72 mg/g fw) were obtained in the vermicompost treatment in inoculation with bio-fertilizer in the second year and chemical fertilizer in inoculation with bio-fertilizer in the second year. Additionally, the highest amount of phenol (1.15 and 1.19 mg/g fw), respectively, in the treatment of vermicompost in inoculation with bio-fertilizer in the second year and chemical fertilizer in inoculation with biofertilizer in the second year, flavonoids (107.1 mg/g fw), and phosphorus (1.623%) in vermicompost in inoculation with bio-fertilizer in the second year were obtained.Moreover, the results of comparing the means showed that the highest percentages of antioxidant activity percent (36.24) and nitrogen content (2.29%) were in vermicompost in inoculation with bio-fertilizer and chemical fertilizer in inoculation with bio-fertilizer in the second year, respectively. The lowest bulb size (3.16 cm), bulb weight (0.037 kg), phenol content (0.168 mg/g fw), flavonoids (48.99 mg/g fw), total protein (6.81 mg/g fw), phosphorus (0.753%), and potassium (0.811%) were observed in control.

According to the results of this study, organic fertilizers can be used in inoculation with bio-fertilizer to increase the production of Iranian shallot as organic fertilizer and not impose a negative effect on the quantitative and qualitative characteristics of this plant instead of, excessive use of chemical fertilizers.

Canola (Brassica napus L.) is known as the third most important oil crop in the world and is now cultivated over a large area of the world's farms in rotation with various crops, especially cereals (Reddy and Redi, 2003). Simulation models are a useful tool for predicting crop responses to different environments. The CSM-CROPGRO model (Jones et al., 2003) was integrated into the Decision Support System for Agrotechnology Transfer (DSSAT) for simulating spring rapeseed (Saseendran et al., 2010). Due to limited studies on simulating the growth and yield of rapeseed in Iran, especially using DSSAT models, the purpose of this study was to calibrate and evaluate the DSSAT-CROPGRO-Canola model for simulating the growth and yield of two canola cultivars with different treatments of planting date and nitrogen in Karaj, Iran.

A field experiment was performed as a split-plot factorial based on a randomized complete block design with three replications in 2017 and 2018. Two spring canola cultivars (Dalgan and Hyola-420) were planted under three levels of nitrogen (0, 70, and 210 kg.ha-1) on two planting dates (28 Feb and 19 Mar). Planting date was considered as the main factor, and cultivars and nitrogen levels were considered as sub-factors. Measured data during the growing season were leaf area index (LAI), total dry matter (TDM), yield and yield components, and dates of flowering and physiological maturity. Daily weather data, management events, and soil characteristics are imported to DSSAT. The first-year experimental data were used for calibration, and second-year data were used for model evaluation of developmental stages, LAI, TDM, and grain yield. The performance of the DSSAT-CROPGRO-Canola model during the calibration and evaluation was assessed using different statistics, root mean square error (RMSE), normalized RMSE (nRMSE), Willmott’s index (d), and coefficient of determination (R2) of a 1:1 regression line.

The results of evaluating phenological stages (anthesis day, first pod day, first seed day, and physiological maturity day) showed that the RMSE for the Dalgan cultivar was less than four days, and for the Hyola-420 cultivar, it was less than five days. This indicates that the model performed excellently in accurately simulating developmental stages. The model was able to simulate LAI up to the pod formation stage in different treatments. The nRMSE and d were 24.88% and 0.92 for the Dalgan cultivar and 22.72% and 0.95 for the Hyola-420 cultivar, respectively.The model was also able to simulate the total dry matter at different planting dates as well as different levels of nitrogen fertilizer, and the values of nRMSE, d, and R2 for the Dalgan cultivar were 24.97%, 0.97 and 0.91**. For the Hyola-420 cultivar, the values were 22.73%, 0.98, and 0.94**. Additionally, the nRMSE, d, and R2 values for the number of grains per square meter were 14.97%, 0.98, and 0.91** for the Dalgan cultivar and 15.37%, 0.98, and 0.90** for the Hyola-420 cultivar, respectively.The evaluation results for grain yield of canola cultivars showed that the RMSE was 395 and 265 kg.ha-1, d was 0.97, and R2 was 0.89** and 0.91** for Dalgan and Hyola-420 cultivars, respectively, confirming the high accuracy of the calibration. Therefore, this model can be used to evaluate the different effects of crop management and make decisions in canola cultivation systems. One of these decisions is to determine the best planting date for spring canola cultivars in the region. Based on the long-term model simulation of cultivars in different planting dates, it is recommended to plant spring canola up to 11 March in this region.

The results of this study showed that the DSSAT-CROPGRO-Canola model had reliably good performance under different management and environmental conditions. CSM-CROPGRO-Canola model predicts grain yield responses to management and environmental conditions well and can now be employed for assessing the impacts of various agronomic management strategies and decisions making in canola production systems in Iran.

 There are only a limited number of maps available regarding the distribution of agricultural and horticultural lands in the country. The existence of these maps can play an important role in various fields such as agricultural planning and development, climate change assessment, yield gap, and food security analysis, livestock production systems management, ecosystem service, fertilizer use management, agricultural optimal cropping pattern determination and other studies related to agriculture, forestry, and rangeland. For example, one of the relevant applications of these maps is their use in combination with climate zoning maps and soil maps to select the target meteorological stations in plant production simulation studies with different practical purposes. The SPAM project (Spatial Production Allocation Model) in IFPRI (International Food Policy Institute) is the main source of these kinds of maps. The accuracy of SPAM maps is acceptable at providence or higher scales because they are prepared based on provincial data. However, these maps may not be precise on a smaller scale than the province. The SPAM data bank does not cover all main crops and none of the horticultural plants. Therefore, in this study, the land use maps of 33 main agricultural and horticultural plants were produced at the country scale using the simplified SPAM method.

To generate these maps, a spatial overlay of land distribution (total rainfed land raster, total irrigated land raster, and total garden products raster for target crop) with polygon boundaries of cities was produced in ArcGIS. The value of the pixels in each county must be calculated in the created map. To do this, first, the number of pixels with land in each county was counted on this map. Then the area under cultivation of the target plant in each county was divided by the number of pixels counted in the same county. The number obtained in each county was considered as the pixel value of the land in that county for the target plant. The assumptions about the production of distribution maps for each plant in rainfed and irrigated Conditions are 1- To generate the distribution maps of each rainfed or irrigated annual plant; it is assumed that the distribution of the land of the given crop is the same as the distribution of all rainfed or irrigated lands within each county. It should be noted that this assumption can be incorrect if only the land distribution of the crop is considered in a particular crop year. Due to crop rotation, the distribution of a crop in the lands of a county changes every year. If the land distribution of a particular crop in a county is considered for a period of 3 years or more, the probability of target crop planting within each part of the county lands will be high. Because in the present study, information from the period 2014 to 2016 has been used, it is assumed that during this period, the distribution of lands the target rainfed and irrigated is similar to the distribution of total rainfed and irrigated lands in the given county. 2- In the case of horticultural crops that are perennial, it is assumed that the gardens of the target crop are distributed uniformly in the horticultural lands of that county. Therefore, the distribution of a particular horticultural crop in a county was similar to that of the total distribution of horticultural lands in that county.

The findings of this study suggest that SPAM2005 maps for various crops in Iran were less accurate than SPAM2010 maps at the province level. While the area of crops in SPAM maps was similar to statistical data at the province level, the spatial distribution of crops required modification. This issue became apparent when the grassland distribution map was compared with the crops SPAM maps, indicating that some crop land in SPAM maps was incorrectly located where grasslands should be. The approach used in this study resolved this problem and generated new spatial distribution maps for crops with higher accuracy.

This study utilized county-level data from over 400 counties to produce more accurate maps than the original SPAM maps. The advantages of the maps produced in this study compared to SPAM maps are (1) The use of up-to-date crop area information to generate the maps; (2) The use of crop area data at the county scale to increase map accuracy; (3) The application of country-specific land distribution maps to generate the maps; and (4) The production of distribution maps for all major horticultural and agricultural crops in the country, creating a comprehensive database in this field.

Water deficit or drought stress is one of the critical abiotic stresses and limiting factors in the productivity of plants, especially in arid and semi-arid regions. In these conditions, the nutrient use efficiency by plant decrease due to the lower mobility of these elements. The application of bio-fertilizers is one of the most important and sustainable strategies for soil fertility management and plant nutrition; in addition to reducing chemical pollution, improves plant growth conditions. The application of arbuscular mycorrhizal fungi (AMF), as bio-fertilizer improves plant nutrients and water uptake and enhances plant resistance to stress conditions leading to improving plant growth and productivity. The objectives were evaluating the effect of different fertilizer sources (chemical fertilizer and AMF as biofertilizer) and harvesting time on the quantity and quality characteristics of peppermint under drought-stress conditions.

To evaluate the effects of different fertilizer sources and harvesting times on the quantity and quality of essential oil in peppermint (Mentha piperita L.) under drought stress conditions, a field experiment was carried out at the Faculty of Agriculture, University of Maragheh, Iran, in 2019. The study followed a split-split plot design based on a randomized complete block design (RCBD) with 36 treatments and three replications. The first factor included three irrigation levels: irrigation after depletion of 30% available water as control, depletion of 50% of available water as mild stress, and depletion of 70% of available water as severe stress. The sub-factor included different fertilizer sources, including control (C), 100% nitrogen fertilizer (NF), arbuscular mycorrhizal fungi (Rhizophagus intraradices) (AMF), 75% NF + AMF, 50% NF + AMF, and 25% NF + AMF. The third factor was harvesting time (first and second harvest). The distance between rows was set to be 4 m, with a plant density of 10 plants per m2. In AM fungi treatments, 80 g of the soil containing mycorrhizal fungi hyphae and the remains of the root and spores (1000 g spore.10-1 g soil) was added to the soil during planting. The aerial parts of peppermint were harvested at 50% flowering stage on the first and second harvests. The data were analyzed using analysis of variance and mean comparison based on the least significant difference (LSD) test with SAS 9.3 statistical software.                                                                                                                          

The results showed that plant height, number of nodes per plant, number of leaves per plant, number of lateral branches per plant, SPAD index, dry matter yield, essential oil content, and yield were significantly affected by the interaction of fertilizer sources x irrigation levels, harvesting time, and harvesting time x irrigation levels. The highest and lowest values of morphological characteristics, leaf greenness, dry matter yield, and essential oil yield of peppermint were achieved under non-stress conditions with the application of 75% nitrogen fertilizer + AMF and severe water stress without fertilization, respectively. The maximum (2.4%) and minimum (1.2%) of essential oil content were observed under mild water stress fertilized with 75% nitrogen fertilizer + AMF and severe water stress without fertilization, respectively. The main essential oil compounds were menthol, menthone, 1,8 cineol, and menthofuran. The highest menthol and menthone content were recorded under mild water stress fertilized with 75% nitrogen fertilizer + AMF and non-stress conditions fertilized with 25% nitrogen fertilizer + AMF. The first harvest showed higher values of morphological characteristics, dry matter yield, essential oil content, and yield compared to the second harvest due to the longer growth period and better growth conditions in the first harvest.

The results demonstrated that the plant height, the number of nods per plant, number of leaves per plant, the number of lateral branches per plant, SPAD index, dry matter yield and essential oil yield decreased significantly with increasing stress levels. In contrast, the application of AMF reduced the adverse effects of water stress, so that in severe water stress conditions (irrigation after depletion of 70% available water), individual and integrative application of AMF with nitrogen fertilizer increased the mentioned traits when compared with control. In addition, the mentioned traits in the first harvest increased by 127.8, 194.6, 159.8, 147.7, 17.7, and 37.9% in comparison with the second harvest. Also, the essential oil content of peppermint is enhanced with increasing water stress to mild stress. So, the essential oil content in mild stress increased by 11.4 and 39.7%, respectively, when compared with non-stress and severe stress. The highest essential oil yield was achieved at the first harvest with the integrative application of 75% NF+ AMF. Also, the major essential oil compounds of peppermint (menthol) was recorded in mild stress integrated with 75% nitrogen fertilizer+ AMF. Generally, considering that the economic purpose of cultivating medicinal plants is extracting the maximum content of secondary metabolites, and since the productivity of peppermint essential oil increased significantly by the integrative application of 75% nitrogen fertilizer+ mycorrhiza in mild stress, it can be suggested as a superior treatment.

The incidence of drought periods and its continuity in arid and semi-arid areas is considered one of the factors affecting soil microbial population and activity and soil water content, and thus affect soil fertility and nutrient availability. Implementation of the straw checkerboard barrier technique in these areas as a cheap, effective, and easy technology has an important role in reviving soil microbial communities and desertification control. In the present study, the effect of the straw checkerboard barriers technique on moisture retention, soil microbial population and their CO2 production was investigated.

This research was carried out in a semi-arid region prone to wind erosion with damaged soil communities, in which the straw checkered barrier technique was established to control wind erosion. For this purpose, 5 t.ha-1 of rice (Oryza sativa L.) straws were arranged in 1 m × 1 m checkerboard patterns in January 2018. This research was carried out in a part of the “ Margh” meadow the south of Shahrekord, the capital of Chaharmahal and Bakhtiari province (50° 50 ́E, 32° 17 ́N). Then the effect of this technique on soil microbial properties, including respiration and soil microbial biomass as well as moisture retention and aggregate stability, were considered. The same area was also dedicated for control as bare ground. Several straw squares were randomly selected, and the trend of changes in microbial respiration and soil moisture in the border of barriers, the center of barriers, and bare ground were measured in several stages. Also in the fourth stage of microbial respiration determination, microbial biomass, and aggregate stability were measured too. Microbial respiration and soil moisture data were analyzed based on a split-plot experiment in time in a randomized complete block design, and microbial biomass data and weight and geometric mean particle diameter were analyzed based on a randomized complete block design.

The results indicate that soil water content at the borders of the barriers significantly increased compared to the center of the barriers and the bare ground by 10.91% and 18.56%, respectively. Soil water content at the borders of the barriers was maintained for a longer time compared to the bare ground, but the decreasing trend of soil moisture in the bare ground was steeper over time, reaching the lowest position compared to the others. This can be attributed to the reduction of wind speed and shading of straws on the soil surface, creating a safer microclimate near the soil surface. The addition of rice straw in the form of checkered barriers to the soil significantly increased carbon mineralization compared to the bare ground in all measurement stages. In the first stage, the amount of CO2-C produced at the borders and center of the barriers increased by 37.76% and 14.69%, respectively, compared to the bare ground. On July 5th, CO2-C production decreased significantly. From July 15th to October 28th, the trend of carbon mineralization at the borders and center of the barriers and bare ground showed a steady state with lower values for the bare ground. Residue incorporation in soils may increase C mineralization and have a positive priming effect for accelerating soil organic carbon (SOC) decomposition. The establishment of straw checkerboard barriers alleviated the effects of moisture deficiency on soil microbial activity and increased carbon mineralization. The higher rates of microbial respiration in the barriers indicate the efficiency of the straws added to the soil and the better adjustment of drought conditions in the soil. The highest soil microbial biomass and aggregate stability were observed at the borders of the barriers, which was significantly different from the bare ground. The return of residues to the soil increased aggregate stability, which may be due to the improvement of organic matter and soil porosity.

The results of this study indicate that the implementation of straw checkerboard barriers improved the soil's biological properties, moisture content and aggregates stability and can provide a better microclimate for plant establishment and growth, which may lead to higher conservation of natural resources and sustainable production.

Introduction:

Rice (Oryza sativa L.) is one of the most important and valuable grains in the world, after wheat, and is the main source of food for more than 50% of the world's population. Proper water management in rice fields plays a key role in the usefulness of other production inputs. One way to improve the efficiency of nitrogen fertilizer application and reduce its losses is the simultaneous use of organic and biological fertilizers. Due to the conditions of Iran in terms of water resources and excessive consumption of nitrogen fertilizers, the use of less water in rice cultivation and reducing the use of chemical fertilizers can play a very important role in saving and wasting water by using biofertilizers will reduce the cost and pollution of chemical fertilizers.

An experiment in the experimental farm of Rice Research Institute of Iran (Rasht) performed over two years, 2017 and 2018, to evaluate the response of two rice cultivars to bio-chemical fertilizers at different irrigation levels on leaf area index, yield, components Water performance and efficiency were assessed. This experiment was performed in the form of double split plots based on a randomized complete block design with three replications. Accordingly, experimental factors including water management at three levels without stress (flooding) and irrigation intervals of 10 and 15 days as the main factor, fertilizer at three levels including inoculation of seedlings with nitroxin biofertilizer, inoculation of seedlings with nitroxin biofertilizer + 50% of nitrogen chemical fertilizer required by the plant (combined fertilizer treatment) and 100% of nitrogen chemical fertilizer required by the plant) as a secondary agent and rice cultivar at two levels including Hashemi and Gilaneh as a secondary agent. The dimensions of each plot were 3Ï3 meters. In this experiment, grain yield, grain yield components, leaf area index, and water use efficiency were examined.

The results of this experiment showed that there was no significant difference between the combined treatment of fertilizer (2.77 t/ha) and the treatment of 100% nitrogen chemical fertilizer (2.82 t/ha) on the yield of rice cultivars. The waterlogging treatment caused a 23% and 38% higher grain yield compared to 10-day and 15-day irrigation cycles, respectively. The highest leaf area index was observed in the Gilaneh cultivar with 100% chemical nitrogen fertilizer required by the plant and inoculation of seedling roots with the combined treatment of fertilizer during flooding, with values of 4.52 and 4.03, respectively, and the lowest value of 1.48 was observed in the Hashemi cultivar with seedling root inoculation with nitroxin biofertilizer and irrigation for 15 days. Water use efficiency in nitrogen and compound fertilizer treatments was higher in the Gilaneh cultivar than in the other treatments. The Gilaneh cultivar with 15-day irrigation treatment and 100% nitrogen fertilizer required by the plant showed the highest water use efficiency in two years, and the plant needs of this cultivar did not show a significant difference. The combined application of nitroxin biofertilizer and nitrogen chemical fertilizer, in addition to producing a good yield and improving water use efficiency, reduced the use of nitrogen chemical fertilizer by 50%.

By increasing the intensity of stress, seedling root inoculation treatments with nitroxin biofertilizer + 50% chemical nitrogen fertilizer required by the plant and consumption of 100% nitrogen fertilizer required by the plant improved water use efficiency. Biofertilizer, along with nitrogen fertilizer increased the leaf area index and crop yield. Nitrogen fertilizer increased the number of empty seeds per panicle compared to biofertilizer. The Gilaneh cultivar was more successful than the Hashemi cultivar in the studied traits. The use of biofertilizers could be a suitable and desirable alternative to chemical fertilizers, in the long run, to minimize environmental pollution and achieve sustainable agriculture.

In conventional agriculture, crop production has gradually shifted from ecological production principles to economic approaches, which has led to the destruction of natural resources and land use change, as well as the reduction in resource consumption (Koocheki et al., 2016b). Satisfying the nutritional needs of a growing population whilst limiting environmental repercussions will require sustainable intensification of agriculture. The adverse effects of climate change are significantly decreasing yield and yield stability over time in current monocropping systems. We argue that intercropping, which is the production of multiple crops on the same area of land, could play an essential role in this intensification. Intercropping often increases resource use efficiency and agricultural productivity compared with growing the component crops solely and can enhance yield stability (Martin-Guay et al., 2018; Raseduzzaman & Jensen, 2017). In the case of an intercropping strategy, the growing period for the legume, as a cover crop, is longer to provide a high amount of fixed nitrogen and potential ground cover to compete with weeds (Vrignon-Brenas et al., 2018). The land equivalent ratio (LER) is often computed as an indicator to determine the efficacy of intercropping that measures land productivity. LER may be interpreted as the relative area required by sole crops to produce the same yields as achieved in a unit area of intercrop. The objective of the present study was to evaluate the effect of relay intercropping as replacement series of three plant species such as chickpea (Cicer arietinum L.), mung bean (Vigna radiate L.), and sugar beet (Beta vulgaris L.), on the yield, yield components, and land equivalent ratio under climatic conditions of Mashhad.

A field experiment was conducted at the Agricultural Research Station of Ferdowsi University of Mashhad, Iran, during the growing seasons of 2015-2016. For this purpose, a randomized complete block design with three replications was used. The treatments included sole cropping of chickpea (C), mung bean (M), and sugar beet (S), as well as intercropping with 25% L + 75% S, 50% L + 50% S, and 75% L + 25% S. The investigated traits of mung bean and chickpea were plant height, number of pods per plant, number of seeds per pod, number of branches per plant, seed weight per plant, and 100-seed weight, as well as the number of hollow pods per plant, number of seeds per plant, biological yield, seed yield, and harvest index. For sugar beet, the traits investigated were root height, fresh yield of root, dry yield of root, dry weight of shoot, sucrose content, and sucrose yield. The land equivalent ratio of chickpea, mung bean, and sugar beet was calculated (Sullivan, 2003) as follows: LER = Y1/I1 + Y2/I2 + Y3/I3, where Y1, Y2, and Y3 represent chickpea, mung bean, and sugar beet yield in intercropping, and I1, I2, and I3 represent chickpea, mung bean, and sugar beet yield in mono-culture, respectively. SAS 9.2 was used for analysis of variance. All the means were compared according to Duncan's test (p ≤ 0.05).

The results showed that the effect of relay triple intercropping arrangements of three species, such as mung bean and chickpea with sugar beet, was significant on yield components and seed yield, biological yield (p ≤ 0.05). The highest seed yield of chickpea and mung bean (2912 and 1247.83 kg/ha, respectively) and biological yield (6237.5 and 6816.7 kg/ha) were observed in sole culture, respectively. Also, the highest amount of fresh root yield was related to its sole cropping with 65242 kg/ha. The highest and lowest LER were calculated for 75% S + 25% L (with 1.53) and 25% S + 75% L (with 0.94), respectively.

Intercropping systems using ecological principles are one of the sustainable solutions to choosing plants suited to the needs, and competitiveness is very important. According to the results, relay triple intercropping of chickpea, and mung bean with sugar beet can be considered as ecological management and ecological intensification in the agroecosystems.

Crop simulation models are very useful tools for the evaluation of plant growth and development processes. Crop-simulating models may be used to estimate yield and evaluate climatic, plant, and management parameters on yield. Also, it may be used to predict crop water requirements under different conditions. Crop models should be evaluated and parameterized to simulate crop growth and development. Parameterization is used for precise simulation of crop growth and development and can estimate the best and most appropriate values for model parameters obtained via observed data or calibration. The objectives of this study were to describe the SSM-iCrop2 model, determine plant parameters, and evaluate alfalfa (Medicago sativa L.) in its major production regions using the SSM-iCrop2 model in Iran.

SSM-iCrop2 crop simulation model is a simplified form of SSM crop models which is suitable for the simulation of growth, development, and yield of different crops under different environmental conditions and large-scale estimation of crop production, especially in the evaluation of nutrient availability and climatic effects. This model includes sub-models of phenology, leaf expansion and senescence, dry matter production and distribution, and soil water balance. Daily weather data, agronomic management, soil properties, and plant parameters are required for simulation in this model. The present study investigates the performance of the SSM-iCrop2 model regarding the prediction of single cuts and overall cuts, phonologic stages, and water requirement of alfalfa under changing climatic conditions in Iran. To simulate the growth, development and yield of alfalfa using SSM-iCrop2 model in Iran, the major irrigated alfalfa production provinces, including East Azarbaijan, Hamedan, West Azarbaijan, Sistan and Baluchestan, Khorasan Razavi, Esfahan, Kordestan, Ghazvin, Ardabil, Markazi, Fars, Zanjan, Chaharmahal and Bakhtiyari and Tehran were identified based on the data available in Ministry of Agriculture statistics. Then, field experiment data required for model parameterization and estimation were collected from these provinces.

According to the results of the SSM-iCrop2 model parameterization, two cultivars with different leaf area indices (high-yielding and low-yielding) were identified in major alfalfa production provinces. The model was evaluated using independent experimental data that had not been used for parameterization. The evaluation results for alfalfa yield showed that the observed single-cut forage yield ranged from 112 to 640 g.m-2 with an average of 330 g.m-2; the observed total annual forage yield ranged from 646 to 4042 g.m-2 with an average of 1717 g.m-2; and the water requirement of alfalfa obtained from the NETWAT software was between 5140 to 12690 m3 ha-1 with an average of 8746 m3 ha-1. The predicted single-cut forage yield, predicted total annual forage yield, and alfalfa water requirement ranged from 189 to 457 g.m-2 with an average of 351 g.m-2, 693 to 3296 g.m-2 with an average of 1654 g.m-2, and 4093 to 16874 m3 ha-1 with an average of 10940 m3.ha-1, respectively. Overall, in the evaluation of observed versus simulated alfalfa forage yield, 31 points were obtained for single-cut yield with a correlation coefficient (r) of 0.79, root mean square error (RMSE) of 88.3 g.m-2, and coefficient of variation (CV) of 26.78%; and 21 points were obtained for annual yield with an r of 0.90, RMSE of 344.4 g.m-2, and CV of 20.05%. The evaluation results also showed that the observed versus simulated alfalfa water requirement had an r of 0.43, RMSE of 3503 m3 ha-1, and CV of 40%.

The results obtained from parameterization and evaluation of the SSM-iCrop2 model show that the mentioned model presents a logical prediction and accurate estimation of model parameters for yield and water requirement of alfalfa crops in Iran. Thus, this model may be used for the prediction of alfalfa yield under different climates and management conditions.

The length of the growth period is the key to crop adaptation to new environments. It is strongly affected by the environment in such a way that it is possible to predict the length of the growing period based on some correlations with environmental factors. Simple models that quantify intraspecific variability in flowering responses to temperature and photoperiod can be useful for characterizing lines. Quinoa (Chenopodium quinoa) shows considerable resistance to a wide range of abiotic stresses. Cardinal temperatures and day length at each development stage are necessary to find an appropriate model for predicting plant growth and development.

Ten separate experiments (10 planting dates included: 29 March, 29 April, 28 May, 28 June, 26 July, 23 August, 6 September, 20 September, 29 January, and 29 February) were conducted as randomized complete block design with three replications. The experimental factor consisted of five quinoa lines plus one cultivar (Titikaka). Five promising lines were modified at Yazd Salinity Research Center. Four lines belong to the middle maturing group, one to the late maturing group, and the Titikaka cultivar belongs to early maturing group. The time of beginning and end of each developmental stage, including germination, pollination, and seed maturity, was recorded. The response of developmental stages to temperature and photoperiod was used to determine the cardinal temperature and day length of the main developmental stages (emergence, flowering, and seed maturity).

Based on the coefficient of determination (R2) it seems that the quadratic model is suitable for estimating the cardinal temperatures of germination, flowering, and ripening of quinoa seeds. Using both quadratic and segmented models to estimate the length of special days resulted to satisfactory robustness. The results showed that on days with a length of lesser than 12 hours and temperatures lesser than 30°C, the flowering rate increased with a simultaneous increase of temperature and day length. As the day length increased to 14 hours, the rate of flowering development changed more significantly when temperatures were between 19 and 25°C than at temperatures below 19°C. For all lines, increasing the day length or temperature resulting in an increased plant maturation rate (from flowering to seed maturity) at a constant temperature or day length. The optimal temperature range for all developmental stages of quinoa lines was between 20 and 25°C. There was a significant difference in the base temperatures of the developmental stages. The base temperature for germination of quinoa lines was above 0°C, the base temperature for flowering was between -2 and +2°C, and the base temperature for seed maturity was below 0°C. The maximum temperature of all quinoa developmental stages was above 40°C (42-51°C). At low temperatures, the flowering stage was more sensitive than the seed ripening stage. The critical day length for flowering and seed ripening of quinoa lines was between 11.5 to 12 hours.

The optimum temperature range for germination was obtained by 25-34°C, for flowering by 28-21°C, and for seed ripening by15-32°C. The optimum temperature of all developmental stages of quinoa lines was between 20 and 25°C. The optimum day length range for flowering is estimated at 11.37-34.12 hours and for seed ripening by 10.58-12.3 hours. Using the segmented and quadratic models to estimate quinoa cardinal temperature and photoperiod response resulted in the same estimations, although in most values, the quadratic model showed a higher coefficient of determination. In general, the results indicated that the temperature and day length have a compensatory effect on the flowering rate and seed ripening stages of the studied lines.