نشریه بوم شناسی کشاورزی
سال شانزدهم شماره 4 (زمستان 1403)

Fenugreek (Trigonella foenum-graecum L.), is an annual plant found in many countries in Africa, Asia, and Europe, and India is the largest producer in the world. There are two types of fenugreek, one botanically known as Trigonella foenum-gracum and the other Trigonella corniculata (Champa or Kasturi Methi) of the Leguminosae family. The integrated management system is a system in which reducing the use of chemical fertilizers and the combined use of chemical fertilizers and organic materials are considered. Among organic fertilizers, chicken manure is very important due to its high nitrogen concentration, high carbon quality, low carbon-nitrogen ratio, and providing large amounts of important nutrients required for plant growth. The appropriate amount of potassium sulfate fertilizer in the soil facilitates the osmotic adjustment in the soil, as a result of which the osmotic pressure remains in the leaves, and in this way, the plant's ability to cope with drought stress increases. Therefore, considering the mentioned cases and the lack of scientific information in the field of combining fertilizers, in this research, an attempt was made to find a suitable fertilizer combination consisting of chicken manure and potassium sulfate for the fenugreek plant.

To investigate the effect of chicken manure and potassium sulfate on the physiological characteristics of the fenugreek medicinal plant, factorial research was conducted based on randomized complete block design with three replications in the crop year 2021-2022 in Qochan city in the north of Razavi Khorasan province. Experimental treatments included chicken manure at three levels (0, 1000, and 2000 kg. h-1) and potassium sulfate at four levels (0, 1.5, 3, and 5 per thousand). The chicken manure concentrate was given to the ground according to the investigated area before planting. The planting depth of fenugreek seeds was considered to be 1.5 cm. To prevent the binding of seeds, the seeds were covered with fine sand mixed with animal manure. Then, at the 4-6 leaf stage, thinning was done to reach the appropriate density. The first irrigation after planting and subsequent irrigations were done once every six days until the end of the growing season. Also, Soluptas fertilizer was applied as a foliar spray after planting, from the six-leaf stage to the flowering stage, three times with an interval of 14 days. The investigated traits of this experiment included morphological and physiological traits, which were sampled after the plants were fruited and the pods turned yellow by removing the marginal effect.

The results showed that the highest level of secondary and main stem height, leaf dry weight and other growth traits were obtained with the highest level of chicken manure (2000 kg/ha), which of course was not significantly different from the level of 1000 kg/ha of chicken manure. The use of chicken manure, especially in arid and semi-arid areas, which mainly have low organic matter levels, in addition to increasing soil organic matter and availability of nutrients, can improve the physical, chemical, and biological characteristics of these soils. Also, the highest amount of growth traits was obtained with the use of the highest level of Soluptas, i.e. five per thousand. In the interaction effect of two investigated fertilizers, it was observed that the interaction of organic and chemical fertilizers caused a double effect on the investigated growth traits. The level of 2000 kg of chicken manure caused a 16.38% increase in the weight of a thousand fenugreek seeds compared to no fertilization. The weight of 1,000 seeds was 10.408 gr at the 5 per thousand Soluptas level and 8.906 gr at the non-fertilization level. Also, the interaction of chicken manure 2000 kg/ha with each level of Soluptas caused the highest number of pods in the fenugreek plant. The highest levels of both treatments caused an increase of 83.76% and 93.28% of seed and biological yield compared to no fertilization (control level).

In general, it can be concluded that among the simple effects, the highest amount of traits was related to chicken manure, and among the investigated levels in two treatments, the highest yield of fenugreek dry matter was obtained with the consumption of 2000 kg/ha of chicken manure and 5 per thousand Soluptas.

Agriculture plays a very important role in the realization of many of the United Nations Sustainable Development Goals (SDGs). If agriculture is to make a positive contribution to achieving these goals, ensuring the ecological resilience of farmers i.e. improving adaptation capacity of the households as well as the whole production system to a wide range of environmental changes and shocks is crucial. The intensification of climate change caused by global warming and its consequences, including the occurrence of long droughts, floods and other natural disasters, have threatened the food security of subsistence farmers and smallholders in the first place, and the food security of large communities in the long run. Also recently, the covid-19 pandemic and the possibility of similar epidemics have created more concerns. Therefore, the issue of resilience has been highly considered by researchers and international organizations, especially the Food and Agriculture Organization of the United Nations (FAO), so that resilience has been defined as one of the 10 elements of agroecology. On the other hand, numerous research evidences have shown that integrated systems (combination of crop cultivation and animal husbandry) in order to increase structural and functional diversity, increase ecological resilience against severe environmental stresses and climate changes. In addition, integrated systems have different resilience and ecological stability depending on the intensity, amount and type of integration. Therefore, in the recent years large number of researches are conducted to address the resilience of agricultural systems. Since the ecological dimensions of resilience have not been comprehensively investigated in Iran, the purpose of this research is to evaluate the ecological resilience of rural households in Razavi Khorasan province and compare systems based on agriculture, based on livestock and integrated systems of agriculture and livestock. In this research, the recommended method of FAO has been used to evaluate resilience.

The required informations were collected from 87 households from 10 cities within the province by completing a comprehensive questionnaire and face-to-face interviews with households. Data were analyzed using RIMA II-FAO method. Clustering of 87 households based on their corresponding cultivated area of crops, saffron and the number of livestock units was resulted in 4 livelihood groups, including only cropping (G1), the integrated crop-livestock at medium level (G2), only livestock at large level (G3) and integrated crop-livestock both at large level (G4). The resilience of households in each group was evaluated based on 5 components (asset, adaptive capacity, biodiversity, intensification, and use of ecosystem services), each measured by a number of indicators. The scores of 5 components were aggregated after weighting, by using factor analysis, and normalization to develop a composite resilience index in 1-5 scale.

The results showed a significant relationship between the resilience of rural households and the 5 mentioned components where intensification had negative correlation with resilience while the impact of assets, adaptation capacity, biodiversity and use of ecosystem services on household resilience was positive with the highest correlation for biodiversity. The households of integrated crop-livestock groups (G2) and (G4) had the highest resilience compared to households in single enterprise groups i.e. only cropping (G1) and only livestock (G3), with the lowest resilience in G3. In general, the high score of the components of biodiversity, ecosystem services, adaptive capacity, as well as the low level of intensification in small to medium scale integrated crop-livestock systems resulted to more resilient households while large scale single enterprise households had lower resilience despite their higher assets.

Resilience is fundamental bases of sustainability and it refers to the ability of systems to return to its initial state after facing environmental tensions. The main purpose of the present study was to evaluate ecological resilience for agriculture ecosystems of Khorason Razavi province. The main findings indicated that the integrated farmlands with other activities particularly with animal husbandry is much more resilient than pure and monotype farm production systems.AcknowledgementsWe are grateful to the Honorable Vice Chancellor of Research and Technology of Ferdowsi University of Mashhad for providing the costs of this research.

In recent years, attention has been attracted to the environmental pollution resulting from the production of products, and as a result, the interest of the communities to know more about the environmental protection and destruction factors has increased. Eco-labels are defined to respond to this need of society. Estimating the economic value of eco-labels of agricultural products that provide environmental information about products and their production process to consumers, shows what share of the costs necessary to collect such information and data will be paid by consumers and in this way, the value of labels can be determined for consumers. In Iran, especially in Mashhad, where a significant part of fresh agricultural products is irrigated with urban and industrial wastewater and the use of chemical fertilizers and pesticides in the production of agricultural products is common, the implementation of the labeling scheme for fresh agricultural products due to its impact on the health of consumers and the environment is very important. A large number of consumers of the above products want to have information about the level of contamination of these products and use healthier products, and therefore they are willing to pay for providing this information. 

In this research, the evaluation of eco-labels on freshly packaged agricultural products by measuring people's willingness to pay for these products in 11 regions of Mashhad is discussed. In the present study, the contingent valuation method and single bound dichotomous questionnaires were used, and the bid amounts used in the questionnaire were designed using the Boyle and Bishop method. The spike model has been used to measure the willingness to pay and check the factors affecting it.

The results from the questionnaires indicate that out of 150 participants, 27 stated they would not be willing to pay for eco-labels on freshly packaged agricultural products. Consequently, the bids, designed using Boyle and Bishop's method, were applied to the remaining 123 participants. The suggested bid amounts were 10%, 20%, 30%, 50%, and 80%. The results from the spike model show that the variables of marital status, monthly family income, the market where the product was purchased, the importance of the product's appearance, the individual's attitude towards the environmental impact of traditional agriculture, prior knowledge of eco-labels, and the bid amount all have a significant and positive effect. The variables of age and the importance of the shape product packaging have significant and negative effect on willingness to pay. The studied population is willing to pay about 71% more for freshly packaged agricultural products with an eco-label than the sample price without a label. The significant percentage of willingness to pay calculated in this research is due to the fact that the percentage results depend on the price of goods and for goods and services that have a lower price (such as fresh agricultural products considered in this research), the percentage of willingness to pay will be higher. It should also be noted that the statistical population of the present study is the 11th district of Mashhad, whose residents have a relatively high-income level (the opinion of municipal experts). The estimated willingness to pay also indicates the importance of eco-labels for freshly packaged agricultural products.

The studied population is willing to pay about 71% more for freshly packaged agricultural products with an eco-label than the sample price without a label. The significant percentage of willingness to pay for eco-labels indicates the importance of these labels for freshly packaged agricultural products from the consumers' point of view.

Iran is located in the arid and semi-arid region of the world and is considered one of the low rainfall regions of the world (Khatami et al., 2020). The agricultural sector is considered to be the major water consumer, therefore paying attention to the optimal use of water in this sector is of great importance and any saving in this sector is considered an effective contribution to saving water resources (Khajeh Khezri et al., 2018). Selection of suitable cultivation patterns and systems is one of the useful solutions in the optimal use of production resources, including water. In agricultural systems with limited resources, the use of intercropping is of particular importance. It has been reported that between 16 and 22 percent of the production of the agricultural sector in the world is supplied through various intercropping systems (Chamkhi et al., 2022). Many studies have been done regarding the intercropping of two C4 fodder plants in the investigation of their performance under mixed cultivation conditions. The value of LER in corn (Zea mays L.) – sorghum (Sorghum bicolor L.) intercropping under normal irrigation and moisture stress conditions was reported as 1.35 and 1.62 respectively, which indicated the superiority of corn and sorghum intercropping over the monoculture of both plants, especially under stress conditions. In all countries of the world - especially in Iran - research and progress in fodder production, management and exploitation of these plants have received less attention than other plants. This experiment was carried out with the aim of evaluating the quantitative and qualitative performance of two types of forage corn and sorghum in the intercropping system and the responses of these plants to different levels of drought stress.

The experiment was carried out as strip plots based on randomized complete block design with three replications in Hasharabad village, Regan city, Kerman province. In this experiment, the irrigation regimes with three levels were considered as a vertical plot and different proportions of corn and sorghum mixture with five levels as a horizontal plot. The vertical plot includes three levels of irrigation as 100 mm of evaporation from the class A evaporation pan (control), 175 mm of evaporation from the class A evaporation pan (mild stress) and 250 mm of evaporation from the class A evaporation pan (severe stress). The horizontal plot also has five levels of different proportions of fodder corn and sorghum, including monoculture of corn (M), intercropping of three quarters of corn + one quarter of sorghum (3M:1S), one half of corn + one half of sorghum (2M:2S), one quarter of corn + three quarters of sorghum (1M:3S) and monoculture sorghum (S). Quality characteristics included Dry Matter Digestibility (DMD), Water Soluble Carbohydrates (WSC), Crude Protein (CP), Acid Detergent Fiber (ADF), Total ASH and Crude Fiber (CF) were measured and analysis. In order to calculate the benefits of intercropping, the evaluation indicators of intercropping including Land Equivalent Ratio (LER), Actual Yield Loss (AYL) and Intercropping Advantage (IA) were used (Javanshir et al., 2000). Data were analyzed using SAS 9.1 software and the means were separated by the least significant difference test at 5% probability level.

The experimental results revealed that as the irrigation interval increased and drought stress intensified, there was a decrease in total fodder yield, total ash content, acid detergent fiber, dry matter digestibility, and the yield of protein and crude fiber in the fodder. Regarding the effect of intercropping on the qualitative characteristics of fodder, the findings indicated that an increase in the proportion of sorghum in the intercropping system led to a significant reduction in the share of leaves in the total sorghum biomass, water-soluble carbohydrates, acid detergent fiber, and fodder digestibility. The evaluation of the advantage of intercropping based on LER and AYL index showed that the intercropping of 75% corn with 25% sorghum in severe water shortage stress (irrigation after 250 mm evaporation) compared to other ratios intercropping had a higher superiority than the monoculture of the species.

In general, the results of this experiment showed that the use of intercropping, especially under conditions of limited irrigation, can be a suitable solution to improve fodder production compared to pure cultivation.

Intercropping involves cultivating two or more crops together in the same field within a single cropping year. One common method to supply nitrogen to plants is through the use of chemical fertilizers containing nitrogen. However, excessive use of nitrogen fertilizers conflicts with the principles of sustainable agriculture. An alternative approach is to utilize microorganisms capable of nitrogen fixation, such as rhizobial bacteria and non-symbiotic bacteria (Azospirillum, Herbaspirillum, Azotobacter, etc.). The purpose of this study is to evaluate the usefulness of intercropping of Guilan bean (Phaseolus vulgaris) landrace and maize (Zea mays) under inoculation with Rhizobium phaseoli.

The present study was conducted in Talesh, Guilan province as split plots based on the randomized complete block design with three replications. Main factor was use of bacteria at two levels (inoculation and non-inoculation) and the split factor was the ratio of maize-bean intercropping in five levels (monoculture of maize and bean, 25% bean + 75% maize, 50% bean + 50% maize and 75% bean + 25% maize). Maize and bean seeds were planted simultaneously on May 22, 2022. Beans were harvested in late of August and maize was harvested in mid-September. Each gram of inoculant contained 107 bacterial cells. To inoculate with bacteria, the seeds were first coated with arabic gum and then 10 grams of inoculant was added per one kilogram of seeds. Planting was done after half an hour and drying the inoculated seeds in the shade. After measuring seed yield at harvest, various indices were used to evaluate the effectiveness of intercropping, including the Land Equivalence Ratio (LER), Relative Crowding Coefficient (RCC), Competition Ratio (CR), Aggressivity, and Relative Value Total (RVT). The analysis involved variance assessment, mean comparisons, and calculations of intercropping usefulness indices, all performed using R software.

In bean, the effect of inoculation were significant on plant height, number of pods per plant, number of seeds per pod, pod length, hundred seed weight, biological yield, seed yield, harvest index and the effect of intercropping were significant on plant height, number of pods per plant, number of seeds per pod, biological yield, seed yield and harvest index and the interaction effects of two factor were significant on plant height, biological yield and seed yield. In maize, the effect of inoculation were significant on plant height, ear length and grain yield. The effect of intercropping were significant on plant height, ear length, number of grains in ear, grain yield, biological yield and harvest index and interaction effects of two factor were significant on ear length and hundred grain weightUnder both inoculated and non-inoculated conditions, the Land Equivalence Ratio (LER) exceeded 1 across all intercropping ratios, demonstrating the superiority of intercropping over monoculture in these systems. The highest LER and Relative Crowding Coefficient (RCC) were observed in the planting ratio of 75% bean + 25% maize under inoculated conditions, indicating that inoculation enhanced the yield of both species compared to non-inoculated conditions. In the inoculated condition, the Competition Ratio (CR) was greater than 1 for beans and less than 1 for maize across all intercropping ratios. However, under non-inoculated conditions, for the ratios of 75% bean + 25% maize and 25% bean + 75% maize, the CR was greater than 1 for maize and less than 1 for beans. This shift indicates that maize had a lower competitive ability compared to beans in inoculated conditions within the mixed cropping system.  The Aggressivity index for beans was positive under inoculated conditions across all three intercropping ratios, further supporting its competitive advantage. The Relative Value Total (RVT), which combines the RVT values of beans and maize, was greater than 1 in all intercropping ratios, highlighting the economic benefits of mixed cropping compared to monocropping of either species.

In general, for the sustainable production of crops, the intercropping of bean and maize under inoculation with rhizobium bacteria can be one of the suitable solutions to reach the optimal yield performance.

Drought stress is one of the major environmental stresses affecting more than 60% of Iran's area. The use of drought resistant plants, especially Almonds (Amygdalus communis L.)  that grow in hilly areas with calcareous and stony soils, is of great importance. Iran is recognized as the fifth largest almond producer in the world. Almond cultivation not only has high nutritional value but can also contribute to ecosystem improvement, increase farmers' income, and create job opportunities. Fars province is one of the suitable regions for almond cultivation, ranking first in terms of under cultivation of dry almonds and sixth in terms of under cultivation of irrigated almonds. However, almond performance in this province is not satisfactory and is positioned lower. It appears that the province has not fully utilized its potential, and almond cultivation in many suitable lands has been neglected. Therefore, this study focuses on analyzing land suitability for almond cultivation in Fars province by integrating the Analytic Hierarchy Process (AHP) and fuzzy algorithm with Geographic Information System (GIS).

In order to estimate the extent of suitable areas for dry almond cultivation in Fars province, four criteria (including climatic, topographic, environmental adaptation, and socio-economic) and 14 sub-criteria were used. These sub-criteria include elevation, land slope, slope aspects, land use, soil texture, seedling growth temperature, minimum temperature during flowering stage, relative humidity flowering stage, growth cycle temperature, fruit formation and ripening stage temperature, mean annual precipitation, distance from the road, distance from water levels and distance from population centers. The weights of criteria and sub-criteria in the study were calculated using the Analytic Hierarchy Process (AHP) process and Expert Choice software. After fuzzy mapping and combining fuzzy scores with the weights obtained from the AHP analysis, the Fuzzy overlay algorithm was used to overlay different thematic layers (climatic, topographic, socio-economic, environmental adaptation). Finally, the map estimating the extent of suitable areas for almond cultivation was classified into five classes.

In this research, suitable areas for almond cultivation have been identified using Analytic Hierarchy Process (AHP) and GIS. These areas were selected based on 14 different sub-criteria. The findings identified mean annual precipitation as the most critical sub-criterion for almond tree cultivation, followed by elevation, mean seedling growth temperature, and relative humidity during the flowering stage. After fuzzifying the maps and combining the fuzzy scores with the assigned weights, thematic maps were generated for each criterion. Analysis of these maps revealed that the most limiting factors for almond cultivation in Fars Province are climatic conditions (including precipitation, mean minimum temperature during the flowering stage, and temperatures during the fruit formation and ripening stages) and topography (slope percentage and elevation). Despite these limitations, the study found that Fars Province has significant potential for dry almond cultivation. Specifically, the study determined that highly suitable, suitable, and moderately suitable lands for almond cultivation account for 9.02%, 16.46%, and 21.63% of the province's area, respectively. The highly suitable zones, covering approximately 9.02% of the province, are particularly favorable for almond cultivation. Additionally, suitable and moderately suitable zones make up 16.46% and 21.63% of the region's area, respectively, further supporting the potential for almond farming in the province. However, the suitability of about 17.09% of the region for almond cultivation is low, and 5.01% of the province area is unsuitable for almond cultivation. Additionally, around 30.79% of the total province area is not recommended for almond cultivation due to land use types. In general, the northwestern, western, and southwestern areas of Fars province have suitable capability, and the southeastern region of Fars province has unsuitable capability for dry almond tree cultivation. Based on the analysis and results obtained, the importance of proper planning for agricultural crop cultivation and appropriate land suitability analysis for optimal land resource utilization for sustainable agricultural development is evident.

Based on the findings, Fars province holds significant potential for dry almond cultivation development, yet it has not fully utilized all of its capabilities to date. Consequently, it is recommended that the expansion of almond tree cultivation in this province be prioritized. Proper planning and optimal utilization of suitable areas in Fars province, considering environmental conditions and defined criteria, will enhance the performance of almond cultivation and facilitate sustainable agricultural development in this region. The results of this study can be valuable to all individuals and organizations active in the field of agricultural development and land resource management (including farmers and horticulturists in Fars province, officials and policymakers related to agriculture and rural development, researchers, and academics in geology, agriculture, and sustainable natural resource development in Fars province) and assist them in decision making regarding almond cultivation development.

Agriculture is an essential part of every country’s economy and plays a decisive role in income, employment, and food security globally. Agricultural soils are critical for the efficient production of crops and safe food to meet the needs of a growing population. However, improving soil quality is a critical component of sustainable agriculture. Given the socio-economic and political pressure to improve soil fertility and increase agricultural productivity, widespread chemical fertilizer use, beginning in the 1950s and 1960s, led to increased food production at significant environmental cost. Chemical fertilizers and pesticides have improved short-term food production. However, soil degradation, greenhouse gas emission increases, and water pollution risks have emerged through their widespread use. Consequently, excessive use of chemical fertilizers negatively impacts human health throughout the food chain. For example, excessive use of phosphate fertilizers can lead to cadmium pollution, which if ingested can lead to osteoporosis. Excessive use of nitrogen fertilizer leads to the accumulation of nitrites in plants; nitrites combine with amines increasing the risk of cancers of the digestive system, and methemoglobinemia in severe cases. Fertilizer use leads to surface runoff and groundwater pollution contributing to eutrophication and consequently the deterioration of natural ecosystems and reduction of genetic diversity. Rice is one of the main Iranian foods, but the excessive use of chemical inputs in the production of this product has reduced its quality and properties, previous research shows that it is possible to use organic fertilizers in rice cultivation. It can provide nutrients needed by the soil to produce this product. But rice farmers do not have much desire to use it in rice cultivation. In line with this importance, the present study was conducted with the general aim of investigating the factors affecting the use of organic fertilizers by rice farmers during rice cultivation in Dezful county.  

The statistical population of this research in 1401 is made up of 4700 rice farmers of Dezful County, and the sample size was estimated based on the table of Karjesi and Morgan, using the cluster sampling method of 360 samples. Data collection was designed in the form of a questionnaire based on the Likert spectrum scale. The form and content validity of the questionnaire was confirmed by experts' opinion and its reliability was confirmed through Cronbach's alpha and composite reliability.

The results of the structural equation modeling research showed that the variables of self-efficacy (ƛ=0.257; P=0.000), action guide (ƛ=0.222; P=0.000), perceived intensity (ƛ=0.121; P=0.035) and perceived sensitivity (ƛ= 0.100; P= 0.046) and perceived benefits (ƛ= 0.319; P= 0.000) have a positive and significant effect on the use of organic fertilizers among rice farmers in Dezful County. This is despite the fact that the perceived obstacles variable did not have a significant effect in this section. In addition, it can be said that the variables of the health belief framework could explain 67% of the variance of the dependent variable of the research (the use of organic fertilizers in rice cultivation). In general, the results of this research can add new knowledge to the existing knowledge and provide new insights for policy makers in this field to promote and develop organic and safe products. 

This study was conducted with the general aim of determining the factors affecting farmers' willingness to use organic fertilizers in rice cultivation. In this study, the health belief model was used to identify the factors. The results showed that this theory is very efficient in this field because it was able to explain 67% of the variance in farmers' behavior in this field. In general, the results of this study can provide new insights for policymakers in this field in order to produce healthy products.

The decrease in rainfall in recent decades and the occurrence of drought in Iran, which is one of the arid and semi-arid regions, as well as the significant wastage of water in the agricultural sector, have caused many researchers to look for new irrigation methods that lead to improve water consumption. Therefore, the importance of conducting this experiment is to reduce surface water evaporation, save water, reduce leaching and use of nitrogen fertilizer in maize cultivation. Nowadays, due to the decrease in rainfall and the excessive water consumption in the agricultural sector, the importance of water resources management has received more attention from researchers. Therefore, simulation models an effective role in evaluating irrigation management methods to improve water consumption in the agricultural sector. This study aimed to assess the AquaCrop model in terms of simulating the yield and biomass of maize under two methods of irrigation (wick and surface) and nitrogen fertilization (topdressing and fertigation).

This experiment was carried out in 2020 and 2021 in the Faculty of Agriculture of Razi University. Experimental treatments included wick irrigation and surface irrigation (at three levels of 100, 70, and 50%) and two levels of nitrogen fertilizer 100 and 50% of the plant's fertilizer requirement. The statistical design was factorial in the form of randomized complete blocks and was implemented in three replications. In the wick irrigation method, fertilizer was provided to the plant through tanks and in solution. In the surface irrigation method, fertilizer was topdressing on the soil surface. Nitrogen fertilizer was applied in three stages. In each watering, the amount of water used will be measured and recorded through the meter. At the end of the experiment, the data measured in the first and second years were used for calibration and validation, respectively. For both stages of calibration and validation of the model, the measured (observed) and simulated values of yield, biomass, canopy cover, and water productivity were compared and statistically analyzed. For statistical evaluation, root mean square error (RMSE), efficiency coefficient of the Nash-Sutcliffe model (EF), and Wilmot agreement index (d) were used.

The results indicated that the root mean square error (RMSE) for simulating canopy cover development under various irrigation and fertilizer treatments ranged from 1.5% to 6.1% during the calibration stage (2020) and from 2% to 6.4% during the verification stage (2021). The model's efficiency factor (EF) for canopy cover simulation was between 0.91 and 0.99 during the calibration stage and between 0.93 and 0.99 during the validation stage. For biomass simulation, the RMSE values ranged from 1.07 to 2.1 tons/ha in the calibration stage and from 1.4 to 2.9 tons/ha in the validation stage. The model's EF for biomass simulation ranged from 0.87 to 0.98 in the calibration stage and from 0.92 to 0.99 in the validation stage. These results demonstrate the model's high accuracy and reliability in simulating both canopy cover and biomass development across different treatments. AquaCrop simulation results showed that the model was able to simulate water productivity better than yield and total biomass so the coefficient of determination (R2) related to water productivity, yield, and biomass of maize was obtained as 0.82, 0.52, and 0.54 respectively.

The simulation of yield, dry matter, and water productivity in the calibration and verification stage was lower than the actual value in all treatments. The biggest difference between the observed and simulated values of yield, biomass and water productivity was observed in the wick treatment (first and second year). According to the obtained results, it can be concluded that AquaCrop was chosen well and within the expectations for the studied area and the ability of AquaCrop in the field to provide a low irrigation model like the wick method is suitable and practical.

The use of medicinal plants has been done since ancient times and may even be considered the origin of modern medicine. Medicinal plants are a source of biomolecules with therapeutic potential and as a lead to develop new drugs. Black cumin (*Nigella sativa* L.), often referred to as a "miracle herb," is a medicinal plant that has been used worldwide for centuries in the treatment and prevention of diseases such as cancer and diabetes. Additionally, it has been valued as a spice and flavoring agent in products like bread and sweets. Various factors influence the growth and yield of black cumin per unit area, with planting date being particularly significant. The timing of planting affects environmental conditions during the plant's growth stages, influencing the rates of vegetative and reproductive growth, and ultimately impacting yield. Therefore, selecting the appropriate planting time is crucial for the successful cultivation of any crop, including black cumin. The aim of this research is to determine the most suitable planting date of black cumin for this plant and the response of different ecotypes of this medicinal plant to the planting date in the weather conditions of Gorgan city.

In order to evaluate different ecotypes of black cumin in response to planting date in Gorgan, a field experiment with four planting dates was carried out in the cropping year of 2020-2021 at the research farm of Gorgan University of Agricultural Sciences and Natural Resources, Iran. The experiment was carried out in the form of split plots based on completely randomized block statistical design with three replication, in which four planting dates were 18th December, 17th January, 16th February and 18th March as the main plot and thirteen ecotypes (Such as Tafaresh, Gardmiran, Razan, Hamedan, Arak, Esfahan, Semirom, Eqlid, Ashkazar, Zabol, Bajestan, Sarayan and Khaf) with 3 replication were considered as sub-plot. In this research, the attributes of plant height, number of branches per plant, number of follicles per plant, number of grain per follicle, weight of 1000 grains and grain yield were measured. After harvesting, measurements were taken and then the data were analyzed with SAS 9.4 statistical software and means comparison was done with LSD’s test in significance at 5% probability level. Graphs were prepared using Excel software.

The results showed that the interaction effects of planting date and ecotype on plant height, number of branches per plant, number of capsules per plant, number of grains per capsule and 1000- grain weight were significant. However, the main effects of planting date and ecotype on grain yield were significant, and the interaction effects were not significant. With the delay in planting, all measured traits decreased. The highest grain yield was obtained from the first planting date (December 18) with 1245 kg per ha. The highest grain yield was obtained from Khaf (1245 kg.ha-1), Sarayan (1179 kg.ha-1), Bajestan (1156 kg.ha-1), Zabol (1141 kg.ha-1) and Esfahan (1117 kg.ha-1) ecotypes. In contrast, the lowest grain yield was obtained from the fourth (March 18) planting date with 694 kg.ha-1. The lowest grain yield was obtained from Arak and Gardmiran ecotypes with 903 and 890 kg.ha, respectively. With the delay in planting, the grain yield of high-yield ecotypes decreased linearly (8-9 kg.ha for each day of delay in planting), with the difference that the decrease in grain yield in the Bajestan ecotype (5.8 kg.ha for each day of delay in planting) was less than other ecotypes, which indicates the high adaptability of this ecotype to the planting date and environmental conditions of Gorgan. Also, there is a positive and significant correlation between grain yield and traits of plant height (0.73**), number of branches per plant (0.56**), number of follicles per plant (0.83**), number of grains per follicle (0.84**) and 1000- grain weight (0.55**).

In general, the results of this research showed that planting date and ecotype have a significant effect on black cumin yield, and it is recommended to plant high-yield ecotypes in December to obtain higher grain yield in Gorgan and additional tests should be done in this area for final confirmation.