نشریه خشک بوم
سال سیزدهم شماره 1 (بهار و تابستان 1402)

The scarcity of cultivable land for medicinal plant growth in arid regions has resulted in the excessive utilization of pasture plants for medicinal applications. The objective of this study was to investigate the potential of hydroponic and aquaponic systems as alternative approaches for cultivating lemon grass (Cymbopogon citratus). thus, an experiment based on a completely randomized design with five repetitions was conducted in Yazd University and the impact of three different cultivation systems (hydroponic, aquaponic, and soil) on the different characteristics of lemongrass were determined. The results demonstrated a significant impact of the cultivation systems on various morphological attributes of the plant including root length, stem diameter, height, and total plant dry biomass. The hydroponic system improves these aforementioned characteristics by 133%, 33.3%, 40.9%, and 56.5%, respectively, when compared to traditional soil planting methods. The aquaponic was found to be ranked lower than the hydroponic system, but it demonstrated a significant improvement in the investigated traits when compared to soil bed cultivation. The influence of different culture systems on the concentration of macro and microelements (excluding potassium) in the aboveground part of the plant was found to be statistically significant. The hydroponic system exhibited the highest nitrogen concentration, while the highest levels of phosphorus and magnesium were observed in the aquaponic system. Conversely, the soil cultivation system displayed the highest concentrations of calcium, sodium, iron, and zinc. Furthermore, the culture medium had a significant impact on the levels of chlorophyll, protein, fat, fiber, and ash in the plant. However, the investigated treatments did not show any significant influence on the concentration of the plant's proline and carbohydrates. Overall, the findings of this study demonstrate the significant impact of three examined cultivation systems on the morphological, physiological, and biochemical attributes of lemongrass as a medicinal plant. Moreover, the potential utilization of hydroponic and aquaponic beds as viable alternatives for cultivating this plant in arid regions is indicated. However, it is necessary to investigate the economic aspects of lemongrass plant production in the mentioned systems as well as the effect of planting substrate on the secondary compounds of this plant in future research.

The lives of both human and non-human societies are greatly impacted by healthy watersheds today. Improving watershed conditions can improve the lives of dependent communities, in addition to preventing the waste of water and soil resources. To improve the conditions, it is necessary to evaluate the available resources and choose a suitable method to quantify the health of the watershed. The PSR conceptual model approach was used to evaluate the health of the Forg watershed of the Madan city in this research. The fog watershed's health was determined by determining various variables after visiting it and identifying its problems. Subsequently, these variables were measured. In order to eliminate correlation between different variables, the VIF test was used to determine and remove correlated variables before implementing the PSR conceptual model. At the end, according to the remaining variables, pressure indicators, condition, response, and health of the Forg watershed were determined. According to the watershed health assessment of Forg basin, the pressure index falls within the range of 0.44 to 0.79. The condition index is in the range of 0.49 to 0.80, the response index is in the range of 0.20 to 0.69 and the heat index is in the range varies from 0.45 to 0.69. The pressure, condition, and response indicators have average values of 0.61, 0.67, and 0.43, respectively, and are classified as healthy and average. With a value of 0.57, the total health index falls under the average health category. The results indicate that the fog watershed is in a healthy state. To maintain the current situation and improve its health and performance, it is necessary to take proper management and executive actions, taking into account the influencing variables in each subwatershed.

The hydroclimatic data changes over time due to climate changes and human interventions. By examining trends in precipitation, river flow, and groundwater levels simultaneously, scientists and experts can plan water resource management at the watershed level with useful information. The aim of this study is to examine the trends in rainfall data, river flow, and groundwater levels in the Mashhad-Chenaran watershed. No significant trend was observed in the rainfall data on an annual scale, but there is a significant downward trend during the winter season. The results indicate a significant decrease in the annual data for stream-flow and groundwater table. According to the findings, the decrease in the discharge data is greater than the decrease in the precipitation data. Also, the trend of decreasing groundwater levels is greater than that of surface runoff. The environmental flow was finally determined by using Tasman's method. In almost all stations, critical flow conditions (less than the environmental flow) were observed according to the research results. According to the findings, the value of critical conditions increases with a decrease in station elevation and an increase in the area of the watershed upstream of the station.

Water scarcity and drought have challenged the prosperity and development of the agricultural sector, food security and stability of rural settlements. In recent years, the reduction of Sefidroud river inflow to Guilan province, climate change and water demand increase have led to water scarcity in the rural areas and agricultural sector of this province. In the present study, the factors affecting the adaptation of the agriculture sector of Shirkoh village in Guilan province to water scarcity were investigated. In this regard, a comprehensive decision tree was designed with five main criteria and 37 sub-criteria. The results of the analysis of the opinions of 15 experts in the form of pairwise comparisons using the fuzzy hierarchical analysis approach showed that the main criterion of "technical knowledge of the user" with a relative weight of 33.1% is the most important in the adaptation of the agriculture sector of the sample village with water scarcity. Also, the "economic" and "income diversity" criteria are in the next position with relative weight of 25.4 and 19.3 percent, respectively. The three sub-criteria "Development of awareness and information of farmers in times of crisis", "Explanation of adaptation strategies according to the level and understanding of local people" and "Using the advanced irrigation system" that are related to the main criterion "Technical knowledge of the user" with a total relative weight of 44.7% have the greatest effect on the adaptation of the agriculture sector of the studied area. Also, two sub-criteria "Employment in various agricultural activities" and "Development of activities related to tourism" have more than 75% relative weight among the sub-criteria of “income diversity”. The findings of this research have provided a suitable platform for identifying strategies to adapt water scarcity in the agriculture sector of Shirkoh village and formulating a policy package.

This research aims to analyze vegetation changes in desert landforms in the northern region of Isfahan province using Landsat images 5 and 8, specifically TM5 and OLI-TIRS sensors, from 1987 to 2020. For this purpose, 200 images were extracted during the 27 warm months, from June 1 to the end of August. After performing the necessary pre-processing on the images that cover the study region, the landforms were classified using the Topographic Position Index (TPI). Subsequently, the NDVI index was analyzed. The results showed that the pattern of vegetation changes from mountainous areas to lowlands is downward. The analysis of the vegetation index on different landforms, as extracted from the TPI, revealed that the unit of mountains and heights exhibited the highest values, while flat plains such as playas, mud, and clay pans had the lowest values. In general, NDVI values have a decreasing trend from mountain landforms to playas, mud, and clay pans. A significant decrease in NDVI is evident at an altitude of 1400 m (middle pediments). NDVI values increase in mountainous landforms (elevations above 1400 m). On slopes greater than 65° (high stony and rocky lands), the decreasing trend of NDVI has intensified. The NDVI index illustrates four phases of change. The fourth phase, which spanned from 2014 to 2020, exhibited a decreasing trend. During this period, the area covered by this index decreased from 34,380 km² to 34,200 km². The spatial changes of the NDVI index in 2030 indicate that the elevations from Karkas to Marshenan and the areas between Kashan and Ardestan will experience critical conditions. This issue requires the special attention of relevant officials and executives in this field.

In biosphere reserves, biocultural diversity is proposed as the key to the relationship between culture and nature. The use of different methods of strategic management, including SWOT, can ensure the sustainable conservation of the biosphere reserve. The purpose of this research is the application of SWOT model in identifying internal and external strategic factors and strategies of Hamoon biosphere reserve in Southeastern of Iran. For this, internal and external effective factors on biocultural diversity of Hamoon biosphere reserve were developed by distributing 30 questionnaires among natural resources and environment experts. The results showed that among the internal factors, the strongest and weaknesses were the presence of water pits and being located in a dry area, respectively. Among the external factors, the highest points of opportunities and threats were assigned to the management of the relationship between man and nature in the biosphere reserve and the dependence of the wetland on water resources outside the country and the non-commitment of the country of Afghanistan to the water rights of the wetland. The total score of internal factors assessment matrices is equal to 3.05 and the score of external factors is 2.71, also the total score of threats and weaknesses (2.91) is more than the scores of strengths and opportunities (2.84). Due to the greater score of threats and weaknesses compared to strengths and opportunities, defensive strategies are suggested as the best strategies for our study area. Presentation of conservation plans based on the patterns of biosphere reserves, preparation of integrated and consonant biocultural management in relation with policies and decisions between performance organisations, preparation and performance of comprehensive plan of water resources for Hamoon wetland restoration and raising of people awareness and local communities on biocultural values of Hamoon biosphere reserve are the most important suggested defensive strategies. Furthermore, offensive (SO), competitive (ST) and conservative strategies (WO) are presented in the next priorities. These strategies can help in the current and future management and planning of biocultural diversity and more effective decision-making and policy-making of the Hamoon biosphere reserve.

In analyzing the frequency of drought as a multifaceted phenomenon, summarizing the event in one variable reduces the reliability of the results. Bivariate and multivariate drought frequency analysis using copula functions makes it possible to estimate the return period of a drought event with specific intensity, duration and peak. In the present study, the stream drought index (SRI-12) was used to investigate the characteristics of drought using the monthly stream of Barnetin Station of the Esteghlal Minab Dam watershed. Spearman's correlation coefficient was used to analyze the dependence between hydrological drought variables and six marginal distribution functions for their modeling. Then, by using Archimedean and elliptical family copula, the best joint was selected and conditional multivariate analysis of hydrological drought was done. The results showed that gamma, lognormal, and Weibull distributions are the best marginal distribution functions for drought intensity, duration, and peak, respectively. The results of the copula fit show that the best copula function in analyzing the dependence between variables is Frank's copula. The three-variable conditional probability of drought severity in 20, 50, 80, and 100-year continuities and peaks of 1 and 1.5 were investigated. These thresholds were chosen considering that they were the most frequent in the study area. The results showed that the probability of drought intensity decreases with the drought duration remaining constant and the peak increase from 1 to 1.5, but with the drought duration and intensity increasing, the drought peak also increases.

In the methods of utilizing nanometer coatings, it is usually possible to reduce the amount of evaporation by using long chain molecules and spreading them on water and forming molecular monolayers. In this research, quantitative (evaporation reduction rate) and qualitative (chemical parameters) effects of octadecanol monolayer dissolved in ethanol as a chemical evaporation control method were investigated. Every three days, it was sprayed (4% concentration) on the water surface of natural ponds with dimensions of 2×2×2 cubic meters located in Faculty of Natural Resources meteorological research station. Accumulated evaporation for the two measured months in the control pond was 559 mm and in the pond with the octadecanol monolayer was 455 mm. Quantitative and qualitative analysis results in the two-month period between the two control ponds and the pond with octadecanol monolayer from 2021/8/23 to 2021/10/22 were performed based on ANOVA test, by comparing means with Tukey's and Duncan's methods. The octadecanol monolayer sample had a significant difference at 0.05 level in terms of changes in the rate of evaporation compared with the control, and the octadecanol monolayer with 20% efficiency was significantly effective in terms of reducing evaporation. Selected qualitative parameters including electrical conductivity, dissolved oxygen were investigated. The results of obtained data using SPSS software and ANOVA test, showed a non-significant difference due to sig greater than 0.05% of dissolved oxygen and electrical conductivity between the average of the control pond and the ponds with octadecanol monolayer. In the control pond, due to the possibility of contact with the air and more incoming radiation, the concentration of dissolved oxygen increased compared to the pond with octadecanol monolayer. The achieved results showed 5% decrease in electrical conductivity and in dissolved oxygen in the pond with the monolayer of the mentioned composition compared to the control pond. In terms of changes in water surface temperature (physical parameter), which was measured with a thermometer, its average was 24.4 ⁰C in the pond with octadecanol monolayer, while it was 23.11 ⁰C in the control pond with monolayer. Empirically, the effect of a dense layer in reducing evaporation losses is proportional to the increase in water surface temperature.

The purpose of this research was to determine the effects of biostimulats application on the yield and yield components of canola (Brassica napus L.) in a semi-arid region based on Amberje classification in Ilam province. The experiment was carried out as split plots arrangement based on randomized complete block design with three replications. The main plots were two irrigation regimes after evaporation of 80 and 140 mm from class-A evaporation pan and soil moisture compensation to the extent of field capacity in silty clay loam soil texture. The sub-plots were as 1- control (application of chemical fertilizers according to soil test), 2- compound 1 and L-amino acid (glycine, betaine and proline) spraying, 3- compound 1 and fertigation of 5 kg per hectare of humic acid in two stages (after the second irrigation and the beginning of shoot elongation) 4-compound 1 and spraying fulvic acid 5-compound 1 and spraying seaweed extract, 6-compound 1 and the co-application of treatments 2, 3 and 5. In all treatments, foliar spraying was done with a concentration of 5 per thousand at the late rosette stage and the beginning of flowering. Quantitative traits measured were seed yield, number of seeds per pod, number of pods per square meter, thousand grain weight and concentration of nutrient elements. Statistical analysis of data was done with SAS software and mean comparison was done with Duncan's test. The results showed that drought stress caused a significant decrease in yield and yield components, but the combined application of growth stimulants caused a significant increase in grain yield compared to the control. The amount of increase of grain yield without drought stress and under drought stress were 16.2% and 21.1%, respectively. These data indicated the greater effect of growth stimulants on increasing grain yield under drought stress than without drought stress. In normal condition, the application of amino acid significantly increased the grain yield by 14.4% compared to the control. In the condition of drought stress, the best results were obtained by combined application of growth stimulants. The application of growth stimulants improved the absorption of nutrient elements under drought stress. So, in the case of potassium, which is an important element in improving plant growth under drought stress, the application of fulvic acid had a significant effect on the increase of potassium concentration compared to the control, and its concentration increased from 2.9% to 3.8%. Also, the combined application of growth stimulants increased potassium concentration up to 3.6%. The results of this research showed the increase of drought tolerance and the improvement of canola growth with the combined application of growth stimulants.