شهرام بانج شفیعی

The vast country of Iran, due to its location in the arid region of the earth and the lack of rainfall, has suffered from drought and groundwater depletion. The reduction of precipitation and soil moisture has a great effect on soil vegetation. The use of various types of moisture absorbent materials that reduce water consumption and increase the time of plant access to water in the soil plays a big role in water conservation. Plantbac panels are made from cellulose waste and can be used to increase the water retention capacity of the soil in dry areas, especially in desert areas.

In order to investigate the effect of Plantbac panels on the amount of water consumption and growth of Atriplex plant, the research was carried out in the area of Hesarsokh located ten kilometers north-east of Qom city for three years (2019-2021). The experiment was carried out as split plots in the form of randomized complete blocks including 12 plots in three replications. The main plot included irrigation treatments at intervals of 10 days (control) and 20 days, and the sub-plot included two treatments of using and not using Plantbac panels (control). To investigate the effect of Plantbac panels on seedling growth at the end of each growing season in each year, traits including: survival, height and crown diameter of the seedling were measured and compared with the control of the same treatment. Statistical analyzes including minimum and maximum traits, standard deviation, simple variance analysis of variables, compound analysis, comparison of averages with least significant difference (LSD) method for seedling height growth and crown diameter growth traits were performed.

There was no difference in seedling survival in the treatments of using Plantbac and control in irrigation with a 10 days interval. While in the treatment of Plantbac panels and the control, 5% of the seedlings were dried, and in the treatment of using the Plantbac panels, 21% and 40% of the seedlings were seen in the control. Combined variance analysis showed that the simple effects of using Plantbac panels, year and the interaction effect of irrigation in the year on the height growth of Atriplex were significant (P≤0.01). Also, the effect of irrigation treatments, the use of Plantbac panels, the mutual effect of irrigation in the year and the effect of the year had a significant difference in the diameter growth trait of the crown of Atriplex seedlings (P≤0.05). The comparison of the average traits showed that the Atriplex seedlings in the "3rd year × 20 days irrigation interval" had the highest height 6.32 cm, and in the "1st year × 20 days irrigation interval" with 9.75 cm, had the lowest height growth. Also, Atriplex seedlings had the highest crown diameter growth in the "3rd year × irrigation interval 10 days " with 22.11 cm growth, and the lowest crown diameter growth had in the "2nd year × 20 day interval irrigation" with 17.33 cm.

The results of the research showed that the effect of Plantbac panels on the traits indicating the growth of Atriplex is effective. The use Plantbac panels reduces losses in the survival of Atriplex seedlings. In other words, the use of Plantbac panels can have an effect in reducing the losses of Atriplex seedlings in saline lands. Also, the height growth of Atriplex in the treatment of using Plantbac panels was higher than the control. The general results of the research showed that the use of Plantbac panels can have an effect in reducing the losses of Atriplex in saline lands. Also, the diameter and height growth of Atriplex in the following years of planting was higher than the first year, which can be due to the possibility of establishing and improving the soil conditions for plant growth in the following years after planting as a result of using Plantbac panels.

Water saving in the soil during planting is one of the main challenges of biological stabilization, especially in dry and desert areas. The effect of hydrophilic materials in maintaining soil moisture caused that in this study, completely biological hydrophilic panels with the brand name Plantback were used for three years (1397-1399) on Tag Haloxylon persicum in the research station of dry and desert areas of Kashan and compare it with the witness to be tested. For this purpose, seedlings were planted on plantback plates that were placed inside holes 30-40 cm deep. Seedlings were irrigated once every four weeks and once every two weeks for six months in two years (spring and summer) in amounts of 10 and 20 litres for each base. The data were statistically analysed based on the design of two split plots in the form of randomized complete block design using SAS software program and the comparison of means was done by Duncan's method. The results showed that the effect of water consumption treatment on crown diameter, crown volume and biomass amount is significant. From the interaction of the average biomass production in the treatments that were significant, it was concluded that Plantback is more than 20% superior to the average of the control treatments. Therefore, it can be said that the use of Plantback hydrophilic plates in the soil were more effective in reducing water consumption by at least the same amount compared to the control.

Some natural materials such as organic matter can be used to increase the usable water of plant in soil. The Plant-bac plates are made of cellulosic waste and can be used to increase water holding capacity, especially in desert areas. In order to investigate the effect of plant-bac plates on water consumption and growth of Haloxylon persicum Bunge, an experiment was conducted for 3 years in Besat nursery located in the east of Qom province. The main plot consisted of irrigation treatments at intervals of 20 days (control) and 40 days intervals and the sub-plot consisted of two treatments of use and non-use of plant-bac. The results of statistical analysis showed that the effects of using plant-bac and year as well as the interaction effect of irrigation on plant-bac use were significantly different (P<0.01, P<0.05) . Also, combined analysis of traits showed that the effects of irrigation on the use of plant-bac and year for height growth and the effects of using plant-bac and year for seedling diameter growth were significantly different. Comparison of mean traits showed that seedling height increased with age of them in the third year after planting in the treatment using plant-bac with 129.42 cm and seedling height growth with 28.56 cm was higher than other treatments. Also, the diameter of seedlings increased with the age of them in the third year after planting in the treatment using plant-bac with 127.14 cm and the height growth of seedlings with 15.80 cm was higher than other treatments.

Recently, Khuzestan province has been faced by dust storms with a higher mass concentrations and longer durations. Providing the water needed to irrigate the seedlings is one of the basic needs. The potential for runoff production at dust sources has been evaluated in the present paper. For this purpose, the volume and depth of runoff were determined based on the area's hydrologic soil group, vegetation cover and land use layers using the US Soil Conservation Organization (SCS-CN) method at the unit level of the studied areas.The results showed that most of the dust centers with an area of 643300 hectares are covered by barren lands with low vegetation and an area of 522,300 hectares is also included in the hydrological soil group C and D. The calculations derived from the amount of runoff generated in the dust center showed that in South East Dust Center of Ahvaz in the November to January quarter per hectare respectively 80, 120 and 95 cubic meters of water can be extracted. It is possible to produce runoff in the Omidieh-Hindijan dust center in December and January from about 60 to a maximum of 160 cubic meters per hectare, in Hoor Al-Azim-Khorramshahr dust center from 30 to about 80 cubic meters per hectare in the second half of the year and in the place of planting projects that the necessary arrangements must be made to manage the use of this possibility).

To replace oil mulches, this study examined the effect of degradable non-oil mulch under the brand name Nucleus (MA-19). This research assumed that the application of the mentioned mulch in biological stabilization projects has no adverse effects on seed germination and seedling growth. The effect of mulch was studied on the establishment of Haloxylon persicum and Nitraria schoberii in a pot experiment in weather conditions of Research Institute of Forests and Rangeland in Tehran, Iran in 2017-2019. Before the experiment, the seed germination test was made to ensure seeds which having standard germination. After determining the germination percentage of seeds (85-90%), seeds were planted in the greenhouse. Then, the soil surface of the pots was sprayed with mulch for comparison with the control. On the other hand, in potting experiments, which were in the form of planting seedlings, after placing the seedlings in the pot, the soil surface was sprayed with the mentioned mulch. The irrigation of the pots was uniform and equal to the field capacity of the soil and based on the soil moisture curve, which was done only once a month, depending on the weather conditions and temperature. Statistical test and comparison of means according to t-test results showed that mulch treatment did not have any negative effects on germination, viability, height, and diameter of seedlings, and in this regard, used mulch behaves as a control treatment (without mulch).

Today, application of superabsorbent material as plantbac panels to overcome water shortages is considered for improving plant vegetation cover in arid areas. This research was aimed to investigate the effects of plantbac panels on plant establishment and growth of Calligonum comosum L’Herit. in the Kashan Arid and Desert Research Station over three years from 2017 to 2020. The experiment was conducted as a split plot design based on randomized complete blocks in four replications, in which the duration of irrigation (2 and 4 weeks) was considered as the main plot, and the amount of water (10 and 20 liters) and treatment (plantbac and control) as sub subplots. The seedlings were planted in the soils with and without plantbac panels. For each plant, the irrigation was conducted using 10 and 20 l water for two- and four-week intervals. Data were collected and analyzed in terms of plant height, canopy diameter, collar diameter, and survival rate. The results showed that the use of plantback plates increased the examined growth criteria of seedlings. When comparing interactions between treatments, the height, collar diameter and crown diameter of the Plantback treated seedlings showed average 11, 11, and 14.8% superiority to their controls. Furthermore, the interaction effect of irrigation by water consumption was significant for canopy diameter (p < /em> < 0.05), while interaction effect of irrigation by plantbac was significant for plant height (p < /em> < 0.05). The average higher and lower crown diameters of 83 cm and 39 cm were observed by 10 l water in two- and four-week irrigations, respectively.

The purpose of this research was to investigate the interaction between the type of management approach and the type of combating desertification projects on soil fertility function. It is especially important in monitoring and evaluation of these projects. For this purpose, at the first, the range of three types of combating desertification projects including bush planting, constructing a crescent pond and seeding - sowing in two different management approaches, Ecological (Sarbisheh combating desertification project) and socio-ecological approaches ( International carbon sequestration project) in Sarbisheh city of South Khorasan province (which were implemented in 2005) were identified. The reference area was determined in each of them and the profile was dug randomly with five replications. Soil sample was taken from a depth of 0-15 cm. Then, the amount of nitrogen, phosphorus and potassium in soil samples were measured as soil fertility characteristics. The results of analysis of variance showed a non-significant difference between the interaction of management type and desertification index projects on soil potassium content due to the abundance of potassium in the soils of arid regions. However, in relation to nitrogen and phosphorus, a significant difference was observed (P< 0.05). As a result, the highest amount of these elements was observed in socio-ecological management (Respectively 0.19 and 0.005 g/kg) based on bush planting project. Rather, the lowest amount was observed in ecological management based (Respectively 0.14 and 0.002 g/kg) under the same project. The results of this study showed that although bush planting has a greater effect on soil fertility than other projects due to its greater focus on the transfer, planting and irrigation of seedlings and ultimately the increase in vegetation. However, the soil fertility status of this project in the ecological management approach indicates the importance of the type of management, including the implementation, protection and proper operation of projects which will have an important effect on soil fertility performance. The socio-ecological management has thus been able to achieve more success in this field due to the active participation of the local community in all stages of planning, implementation, monitoring and operation, and better protection of the revived areas. Therefore, it can be concluded that although the restoration of the structure and function of the ecosystem is the main aim of all restoration activities, its sustainability process is largely related to the motivation of stakeholders and the effectiveness of economic, social and political mechanisms.

Agricultural lands in Khuzestan province, southwest Iran, have a great ability to produce around 137 types of crops (around 13.5% of the country's production). Around 90% of the farmlands in this region are under irrigation. Therefore, the sustainable management of water resources plays an important role in this area. This study aims to assess the long-term challenges and strategies of water consumption management in the agricultural sector of the province and then to examine the development of crop production with water consumption from 1990 to 2016. Results showed that despite long term drought from 1976 to 2006, the agricultural productions increased around twofold. The area under sugar- cane as the main crop production (about 48%, with water consumption around 36000 m3</sup>/ha) increased from 60946 ha in 2007-2008 to 107142 ha in 2015-2016. Based on the principal aims mentioned above, the following subjects need more attention to improve water efficiency in the future:  providing the best water supply and modified irrigation systems,  formulation of suitable cultivation patterns, providing a provincial water atlas, promoting agricultural knowledge and agricultural subsidies facilities, development of irrigation and drainage systems, improving greenhouse production,  developing modern irrigation systems, and  transferring  the spring cultivation to the winter one.

According to the super absorbent polymer manufacturers, super absorbent polymer can improve the physical properties of light soils to absorb and store more water. This study was aimed to investigate the effect of environmental factors such as salinity and duration on super absorbent polymer to store water in sandy soils. Two separate experiments were conducted using A-200 polymer in the field and laboratory conditions. In the field experiment, a site of sand dune from Kashan desert, Iran, was selected and the soil was mixed with a polymer in a ratio of 0.6% w/w. Then, the soil moisture curves were measured three times at three-month intervals. The water uptake of the mixture was decreased from 13.2% to 4.4% and 3.7% at the first to the third times, respectively. In the laboratory experiment, the effect of soil salinity was investigated on the water uptake of pure polymer. Results showed that the net water uptake of the polymer was strongly dependent on concentration of dissolved salts as well as the valence of ions in the solution. The result also showed that the lowest decrease in the water uptake of polymers was obtained from the mixed sodium chloride and sodium sulfate solution in compare to control, and the highest decrease in water uptake was obtained from the mixed calcium chloride and calcium sulfate solution. It seems that applying superabsorbent polymers is non-economic due to the loss of water retention during the time, affected by environmental factors or the presence of salts (minerals) in the soil. Therefore, it is suggested to use natural absorbent material such as compost and clay soil in natural resources area to supply the water requirements of plants.

This study aimed to investigate the relationship between expression of soil salinity factors and vegetation cover in Foojerd watershed. To this end, the vegetation types in the region and the formation of relatively homogeneous in terms of soil and topography, soil and vegetation were sampled by a systematic random sampling. The samples according to the area consists of homogenous units were determined. In each plot characteristics of range species and percentage of vegetation cover were recorded and soil profiles were dug. Depending on the depth of the soil profile and the depth of the roots of the plants were sampled and conductivity, exchangeable sodium, sodium absorption ratio and absorption of sodium in each of the soil samples were measured. Pearson correlation coefficient of salinity and vegetation type and percentage of vegetation cover were calculated using SPSS18.0 software. The results showed that vegetation has a negative correlation with soil salinity factors. Based on analysis of variance and Duncan were revealed that test the type of plant species were depended on soil electrical conductivity and sodium absorption rate and the percentage of canopy cover was affected by soil electrical conductivity and exchangeable sodium content. So soil sodality is the most important limiting factor to grow vegetation in Foojerd watershed.

P.alba and P.euphratica trees are native poplar species of Iran. P. alba for adaptability, wood production and straightness of stem form and P. euphratica for resistance of drought and salinity are important. The purpose of this study was comparison of the growth and physiological charactristics of two native poplar species and their hybrid ( P. euphratica x P. alba 44 / 9) under saline soil of Garmsar and non-saline soil of Karadj. One-year-old rooted cutting was planted with 3×3 m spacing based on randomized compelete block design with three replications in March 2010. Growth and physiological characteristics of the trees were measured according to standard procedures. Analysis of variance of growth characteristics showed that diameter, height, leaf area, specific leaf area (SLA) and leaf dry matter variables had a significant differences among poplar clones. P. euphratica and its hybrids had the highest survival percent, diameter and height values in saline soils of Garmsar. P. alba 44/9 and 58/57 clones had the lowest leaf area value in saline soils. Hybrid clone had the highest survival percent, diameter and height values in Karadj. Analysis of variance of leaf physiologic characteristics showed that chlorophyll a, chlorophyll b and carotenoids values had a significant differences among poplar clones. P. euphratica and its hybrids had more proline, soluble suger and relative water content (RWC) values than P. alba clones in saline soil. Finally P. euphratica and hybrid clones had suitable potential for wood production and resistance to salinity on saline soils of Garmsar station.

Due to the limited water resources and low rainfall, finding proper solutions to reduce the water consumption for vegetation production in natural areas has received attention more than ever before. For this purpose, this research was aimed to investigate the effects of superabsorbent polymer and Plantbac panels on the efficient use of water on Saxaul (Haloxylon persicum) growth. The study was conducted in the Agricultural and Natural Resources Research Station in Semnan province, Iran. Irrigation in this study was performed according to the soil water suction, reaching to pressures of 1.0, 5.0, and 15.0 bars. The water consumption in each of the aforementioned suctions was to reach the field capacity of the same soil. In addition to the above treatments, rainfed treatment was also considered. Before planting the seedlings, the superabsorbent polymer was mixed with the soil of seedling pits at a weight ratio of 0.6%. The Plantbac panels were placed in the bottom of the pits at dimensions of 60×60×50 cm. Therefore, treatments consisted of superabsorbent polymer and Plantbac panels. The experiment was conducted as a split plot design based on randomized complete block, in which soil water suctions levels were considered as main plot and superabsorbent polymers as sub-plot. The results of the combined effect of both water suctions and superabsorbent polymer showed that the water consumption at these suctions was reduced by prolonging the irrigation intervals to reach higher suctions (more negative). At a soil water suction of 5.0 bars, the water consumption for each seedling was 157 liter, showing 33% decline as compared to the soil containing polymer at the same suction. However, at a suction of 15.0 bars, water consumption in the Plantback declined to 34%. Our results clearly showed that the Plantbac panels could significantly increase the Saxaul growth in different irrigation levels more than that recorded for the control and polymer treatments.

In this study the effect of temperature, evaporation or evapotranspiration, precipitation, hillside direction and altitudinal classes, texture and acidity of soil on organic carbon content in the depths of 15 and 45 cm were evaluated. Paired t-test results showed that there is a significant difference between measured parameters in two soil depths. After preparing required data and processing them, outlier's data were removed. Then, base maps for each of the information layers were prepared by Arc GIS9.3 software and all relatd information fit together by overlapping them. Pearson correlation between environmental factors and soil organic carbon values were calculated and it was found that in the depth of 15 cm, the correlation between soil organic carbon values and two environmental factors including temperature and altitude were significant at the level 0.01. As well the results of statistical analysis by using principal component analysis (PCA) method showed that the factors temperature, evaporation (1%), and silt and clay (5%) have had a significant effect on the amount of soil organic carbon. The first, second, and third axes with eigenvalues of 98/4, 78/3 and 92/1, respectively, explained the values 0.33, 0.25, and 0.13 % of correlation between organic carbon and environmental data.

This research was aimed to investigate the relationship between the distribution of range species including: Astragaluss microcephalus, Bromus tomentellus, Onobrichis cornuta and some soil physicochemical properties. After overlaying the maps of land-use, slope percentage, and geology, and forming the homogenous land units in the Zilber Chay Watershed, 35 soil samples were taken by stratified random sampling method. Soil physicochemical properties including texture, pH, EC, lime, and organic matter were measured. The soil factors related to each of these range species were obtained by overlaying the maps of range species distribution with land unit maps. First, the relationship between the presence of these range species with soil factors was investigated using logistic regression method. Then, the vegetation density map was prepared using Landsat satellite images and NDVI index for the land units in which the range vegetation type As.mi-Br.to-On.co was found. The values of area density percentage for the vegetation cover related to the range type As.mi-Br.to-On.co were calculated using area density model. According to the results of paired samples test, there was no significance difference among the measured values at 0-15 and 15-45 cm soil depths, except for soil acidity and electrical conductivity. The statistical analysis of the relationship between soil physiochemical properties at 0-15 and 15-45 cm soil depths was performed using multiple linear regression method. The determination coefficient of multiple linear regression model was calculated to be 0.24, 0.31, 0.32, 0.42 and 0.69, respectively, for the vegetation densities of 30, 50, 65, 85 and 100% at 0-15 cm soil depth. In addition, the regression coefficients of soil acidity and electrical conductivity were calculated to be 0.24, 0.31, 0.32, 0.42, and 0.69, respectively, for the vegetation densities of 30, 50, 65, 85, and 100% at 15-45 cm soil depth. This result indicated that the vegetation density of As.mi-Br.to-On.co was affected by the amount of organic matter, pH, and soil texture at 0-15 cm soil depth in the study area.

A pot trial was conducted to investigate the effect of a superabsorbent polymer on the growth of Panicum antidotale and nitrogen leaching in three soil textures (heavy, medium and light-textured soils) and three irrigation regimes (4, 8, and 12-day intervals). Results showed that the greatest amount of plant growth and dry biomass was obtained at moderate-textured soil and 14-day irrigation interval. According to the obtained results, the effects of polymer, irrigation regime and soil texture on dry matter production, plant height, and nitrogen leaching were significant. Furthermore, the interaction effects of irrigation regimes and soil texture on dry matter production and nitrogen leaching were significant. The highest dry matter production (7.2 g) was obtained at medium-textured soil with polymer at a four-day irrigation interval. In treatments without polymer at a light-textured soil and a 12-day irrigation interval, plants were lost before harvesting. Our results clearly showed that the studied treatments caused to the increased height of Panicum antidotale. Statistically, the effects of a four-day irrigation interval and a heavy-textured soil were the most significant. In addition, the effects of polymer, irrigation regimes, and soil texture treatments on nitrogen leaching were significant. The interaction effects of irrigation and soil treatments showed that the amount of nitrogen leaching decreased by increasing irrigation intervals. The application of polymer obviously decreased nitrogen leaching from 880 mg N/l in control treatment to 550 mg N/l in soils containing polymer material.

Many natural fires occur in arid and semi arid rangelands that may result in destruction of desirable forage and also erosion of valuable rangeland's soil which eventually will lead to great environmental and financial losses. To study the effects of fire on soil physical and chemical properties, a research project was defined and carried out in semi steppe rangelands of Kordan located in southern Alborz Mountain north east of Karaj city. A randomized completely block design was used with two treatments (control and burned rangelands) and 15 replications in year 2008. Soils of the studied area (control and burned rangelands) were examined using sampling in the first spring season after fire was occurred. In each quadrate, percentage of canopy cover was measured. Statistical analysis was performed through factorial experimental design and means comparisons were done by Duncan's test. According to the results of soil analysis, amount of total N, absorbable phosphorous, absorbable calcium and soil organic carbon decreased after the fire. Magnesium absorbable, Cation exchange capacity and percentage of clay increased after the fire. Fire also had no significant effects on the percentage of sand, silt and soil bulk density.

To improve the nutritional status of Acer negundo trees, a three- year experiment was conducted in the National Botanical Garden of Iran which is currently suffering under low soil nutrient availability and occasional symptoms of yellow leaves. Firstly, samples were taken from both weak and vigorous trees in different stands located inside and outside the project site. Next, a factorial experiment based on a randomized complete block design with four replications was conducted, in which the factor A included the application of organic, inorganic and mixed fertilizers. The factor B included two levels of applying fertilizer via 1) solution in the irrigation water and 2) deep placement. The leaf samples were analyzed at growing season for NPK. Statistical comparison of means based Duncan's test showed an increment of N and K elements in leaves compared to control samples following two-year fertilization. Furthermore, an analysis tree vitality based on leaf chlorophyll availability and leaf nutritional status showed no differences in leaf P concentration between fertilizer treatments as a function of fertilizing method. As a conclusion, optimum levels of N and K content in A. negundo leaves are 1.90 % and 1.20 %, respectively.

Trees as alive components of an ecosystem are able to convert some of the environment contaminants to unharmful substances and store some of them in their tissues and reduce their density and intensity in the air and soil by breath، root absorption and photosynthesis and other biotic functions. Trees function in such condition is completely related to environmental and habitat circumstances and their physiological potential. At beginning، five research sites at Khuzestan and Bushehr provinces were selected among the contaminated area by the Gulf War. At each site، soil sampling was made from three levels of depth (0-20، 20-40 and 40-60 cm). Soil physical and chemical characteristics test was made to measure nine metal elements and 12 other soil properties. The eucalypt species consisted of: E. camaldulensis، E. camaldulensis 9616، E. microtheca and E. sargentii which were planted under the Randomized Complete Blocks statistical design with three replicates. Before sampling the trees for determining the contaminant elements. Three individual trees were selected at each plot per one replicate to make sampling for leaf (four specimens per tree at four mean geographical directions). The data were analyzed under the variance analysis and Duncan test programs، using Excel and SAS computer soft wares. Overall، amount of the contaminants in different sites and at three levels of depth was not significantly different. The best eucalypt species and the best sites for absorbing the contaminants in their leaves are respectively as follows: 1- E. camaldulensis، E. microtheca، E. sargentii and E. camaldulensis 96162- Dezful، Isvand، Shooshtar، Karkheh and Kaki. The species which made the best performance in relation to their site interaction are respectively as follows: 1- E. microtheca firstly at Karkheh and shooshtar sites and secondly at Dezful and Isvand sites. 2- E. camaldulensis 96163- E. camaldulensis and E. sargentii.

The main objective of this study was to assess the effects of different levels of vermicompost and nitrogen on qualitative and quantitative yield of chamomile (Matricaria chamomilla L.). The experimental design was factorial based on Randomized Complete Blocks Design (RCBD) with three replications, conducted in Research Institute of Forests and Rangelands during spring 2010. Treatments were consisted of four levels of vermicompost (5, 10, 15 and 20 tons per hectare) and nitrogen of four levels (30, 60, 90 and 120 kg per hectare). The measured traits included number of flowers per plant, diameter of flower, dry and fresh flower yield, essential oil percentage and Chamazulene content in essential oil. Results showed that vermicompost had significant effects on dry flower weight and essential oil percentage (α ≤ 0.05%). In addition, it had significant effects on dry and fresh flower yield and Chamazulene (α ≤ 0.05%). The effect of nitrogen on the number of flower (α ≤ 0.05%) and essential oil percentage (α ≤ 0.01%) was significant. The results of interaction effects showed significant differences for the number of flower, dry flower yield, dry flower weight, essential oil percentage and Chamazulene.

The effect of different level of polymer water absorbent (supper A200) mixed with desert sand were studied in comparing to pure sand and clay soil on survival and growth of Panicum antidotale in pot condition in Research Institute of Forests and Rangeland, Tehran, Iran for three years. The polymer treatments were 0.2%, 0.6% and 1.0% W/W. The irrigation period was determined based on field capacity of pure sand for all treatments. The results showed no significant differences among treatments for plant growth in the first year. However, the treatment of sand with 0.6% polymer had the most survival plants with average values of 100%. The pots were not irrigated in the 2nd year because there were enough precipitations. All survived plants from 1st year were dead at the end of 2nd year. So, the experiment was repeated at the 3rd year. The results showed significant differences among treatments. The survived plant for clay treatment with average values of 6.17 g dry matter per plant had higher production and followed by 0.6% and 1.0% W/W polymer treatments mixed with desert sand. Those treatments had significant differences with pure sand controls. The lower amount of dry matter was obtained by control pure desert sand with average values of 2.91 g dry matter per plant.

The superabsorbent polymers absorb and retain large quantities of water when applied into the soil. This capability is due to its physical and chemical properties. The objectives of this study were to investigate the effects of soil salts on polymer and manure water uptake ability under repeated wetting and drying cycles. The results showed that 1.0 g polyacrylamide made of Iran, had ability to uptake 184.4g distilled water for the first time absorption. It was much less than the same material that had reported in foreign publications. The ability of water retaining for the same polymers was dramatically decreased to 31, 79 and 83 percent than control treatment(distilled water) for waters with 160, 1000 and 2000 mg/l salt concentration, respectively. By 9 times repeated wetting and drying cycles, the ability of polymer had decreased to 22 percent of the first times absorption. As consequently, the amounts of water uptake had also decrease to 72, 81 and 88 percent of distilled water in the same salts after 9 times repeated wetting and drying cycles. At the hottest times of the summer, drying of poly acryl amide super absorbent had take 6 and 2.3 days for distilled and salty water, respectively. The results showed that the negative effects of Na+ were less than those for Ca2+ and Mg2+ on polymer water absorption. For completely decayed animal manure, the retaining of distilled water was 2.3g for 1g dry manure. For water having 4000 mg/l salts concentrations, the uptake ability of manure was not significantly different than distilled water. The drying period of manure had taken the 17 and 18 days for distilled and salty water, respectively.

The National Botanical Garden of Iran (NBGI) with an area of 145 hectares contains various plants with different ecological requirements, including trees, shrubs, herbs and ornamentals. Weakness and decline of some tree species including Elm trees of botanical garden is one of the problems, which considered as the main priorities to be investigated by the garden authorities. Soil productivity and plant nutrient were concerned to be studied. For this reason, soil samples were taken from three layers of each profile (0-10, 10-30 and 30-100 cm) around Elm trees, after studying the soil profile morphology. Leaf sampling was made at appropriate time in order to test N, P, K at first year and N, P, K, Ca, Fe, Mn and Zn at second year. Results showed that the soil texture was sandy, organic mater was low and pH was alkaline. The mineral elements were lower than the optimum range in soil and tree leaves. It can be concluded that increasing soil organic matter, adding adequate amount of manure and chemical fertilizers to soil and applying appropriate irrigation regime might improve the plants health and growth and prevent their decline.