نشریه بوم شناسی کشاورزی
سال هفتم شماره 2 (تابستان 1394)

Soil salinity is one of the major agricultural problems and it is limiting crop productivity in many parts of the cultivated areas all over the world. Saline soils are differentiated by the presence of great ratios of Na/Ca، Na/K، Ca2+، Mg2+، and Cl/NO3 (Gratan & Catherine، 1993) and high levels of neutral salts in the surface layers، which are resulting from the capillary action (Al-Falih، 2002). Osmotic stress occurs when soluble salts increase in the soils and then results in specific ion toxicity (Agarwal & Ahmad، 2010). Therefore، one of the most important side effects of salinity is nutritional disorders. High concentration of NaCl in the root medium usually reduces nutrients uptake and affects the transportation of potassium and calcium ions in plant. (Gratan & Catherine، 1993) reported that the salinity of soils changes ionic strength of the substrate and it can influence mineral nutrient uptake and translocation. Salinity also changes the mineral nutrient availability and disrupts the mineral relations of plants. Hence، the main purpose of this research is to evaluate the effects of rhizobial bacteria inoculation on K، Ca and Na concentration of wheat (Triticum aestivum L.) in saline soils.

Soil sample was collected from Astan Ghodse Razavi farm، Mashhad Iran، and then was dried and passed through a 12-mesh (approximately 2 mm) screen. Soil sample was divided into three parts and then was placed into three containers. Each container was watered by a different proportion of saline water (EC= 10 dS. m-1). Salinity of soils was regularly monitored until three salinities (2، 6 and 10 dS. m-1) came out. Then، a completely randomized design with a factorial arrangement was carried out in a greenhouse condition. The experimental factors included four levels of inoculation (Sinorhizobium meliloti، Bradyrhizobium japonicum and Rhizobium leguminosarum and control) and three levels of soil salinity (2، 6 and 10 dS. m-1) with three replications. Wheat seeds were sterilized in 5% sodium hypochlorite for 2-3 minutes and were washed several times and then were germinated and seedlings were inoculated with bacterial strains. Inoculated wheat seedlings were grown in 1 kg pots. Wheat seedling was watered with sterilized water for one month and was harvested for chemical analysis. Potassium and sodium concentrations in plant tissues were determined by flame photometer and calcium concentration was measured by using Atomic absorption spectroscopy (AAS).

The results showed that the root and shoot dried weight، K and Ca concentrations and K/Na ratio in wheat shoot were significantly decreased with increasing soil salinity. The lowest shoot and root dry weight were observed in high level of salinity (10 dS. m-1). Inoculation of wheat seedlings with rhizobial bacteria had a positive effect on shoot and root dry weight. The highest shoot and root dry weight were obtained when wheat seedlings were inoculated with Sinorhizobium meliloti in non-saline soil treatment (2 dS. m-1). Calcium concentration increased significantly in all levels of salinity when wheat seedlings were inoculated with Rhizobium leguminosarum. Among all tested strains، Rhizobium leguminosarum had a prominent effect on growth of wheat seedlings. With increasing soil salinity، the concentration of sodium increased in shoot and root tissues and K/Na ratio declined dramatically. The lowest K/Na ratio was found in the highest level of salinity (10 dS. m-1). On contrast، the K/Na ratio in wheat shoot was amplified when wheat seedlings were inoculated with rhizobial strains. The highest K/Na ratio was observed in Rhizobium leguminosarum treatment. There are data that show that wheat cultivars having greater leaf K: Na، K ion flux، and growth improve under saline conditions (Mayak et al.، 2004; Morant Manceau et al.، 2004; Yao، 2010). It seems that Rhizobium leguminosarum reduced the detrimental effect of salinity to some extent. Acknowledgements: This research was partially supported by vice president for research and technology of Ferdowsi University of Mashhad. We thank our colleagues who provided insight and expertise that greatly assisted the research، although they may not agree with all of the interpretations or conclusions of this paper.

Dodder (Cascuta campestris Yuncker) is an annual parasitic plant from the Convolvulaceae family (Mishra et al.، 2007). It wraps around many adjacent dicot and a few monocot plants، penetrates in their vascular tissue and exploits photosynthates، nutrients and water (Lanini & Kogan، 2005). Consequently، the growth، vigor and production of the host plant will be severely reduced (Nadler-Hasasr & Rubin، 2003). Dodder is not able to complete its cycle، if it is not attached to a host. Therefore، it is entirely dependent on its host for supplying water، assimilates and minerals (Mishra et al.، 2007). Considering the nature of dodder habit، it is rarely possible to completely control dodder by using different chemical herbicides (Lanini & Kogan، 2005). In addition، because of increasing the environmental concerns caused by applying synthetic herbicides، there is considerable attention to alternative strategies for weeds management (Batish et al.، 2002; Bowmik & Inderjit، 2003). In recent years، allelopathic plants، an alternative strategy for weed management، have received massive attention (Narwal، 2010; Jamil et al.، 2009). Due to the importance of dodder as a parasitic weed، this research was conducted with the purpose of studying the allelopathic effects of aqueous extracts and decay durations of caster bean (Ricinus communis L.) organs on germination and emergence of dodder.

The current study was conducted based on three separate experiments using a completely randomized design (CRD) with factorial arrangement with three replications. The first experiment was conducted in petri dishes and consisted of caster bean organs at four levels (root، stem، leaf and total plant without inflorescence) and their aqueous extract concentrations at 11 levels (0، 1، 2، 3، 4، 5، 6، 7، 8، 9 and 10%). The second experiment was conducted in pots and factors were caster bean organs at 4 levels (root، stem، leaf and total plant without inflorescence) and their aqueous extract concentrations in 5 levels (0، 2. 5، 5، 7. 5 and 10%). The third experiment was conducted with caster bean organs at 4 levels (root، stem، leaf and total plant without inflorescence) and decay durations at 8 levels (0، 15، 30، 45، 60، 75 and 90 days of decay and control). All experimental data were analyzed by ANOVA and the means were separated by Duncan''s multiple range test at 5% probability level.

The results of the first and the second experiment showed that aqueous extract of caster bean organs has a significant effect on dry weight، length of seedling and germination of dodder. From the third experiment، decay duration had a significant effect on the mentioned traits. Leaf aqueous extract in comparison with other organs had the most effect on the studied traits. The complete suppression of emergence was observed in 0، 15، 30 and 45 days of decay by using caster bean leaves. In conclusion، caster bean residues showed great potential for reducing germination and growth of dodder. Therefore، allelopatic potential of caster bean can be considered as a sustainable approach in integrated dodder management systems. In the future، the effective concentrations of aqueous extracts of caster bean organs may be useful as sources for producing biological herbicides.

Canola is the world third oil crop with 25 to 55 percent oil content (Hezbavi & Minaei، 2008). In recent years، tendency towards expansion of the acreage of canola in Iran has been increasing and for the years 2010-2011 an area of 93000 ha with a total production of 190000 tons has been reported (Ministry of Jihad of Agriculture، 2013). Application of biological fertilizers which are environmentally friendly agents have been reported to enhance yield and quality of different crops (Shoghi Kalkhoran et al.، 2012; Afrasiabi et al.، 2011). The purpose of the present study was to investigate the effects of biological fertilizers on quantitative and quality criteria of canola. For this study، a factorial arrangement based on randomized complete block design and three replicates was used. The experimental treatments were three canola cultivars namely Okapi، Zarfam and Modena which was combined with four levels of biological fertilizers: Nitroxin، Phosphat solubilizing bacteria (PSB)، Nitroxin+PSB and a control. Seeds were planted in plots of 2×3 m2. All field managements were carried out based on conventional practices. The measured criteria were plant height، number of pods per plant، 1000- seed weight، biomass yield، harvest index، oil content and yield. The results showed that in all studied criteria except 1000- seed weight there were significant differences between cultivars. Different fertilizer treatments had a significant effect on all criteria except 1000- seed weight and HI. Modena cultivar had the highest oil yield and quantitative characteristics. Composition of phosphate solubilizing bacteria+nitroxin also had the highest oil yield and quantitative characteristics. The interactions between biofertilizer treatments and cultivars in all criteria were not significant. The result of this experiment indicated the effectiveness of use of biofertilizers.

Savory (Satureja hortensis L.) is an annual herbaceous plant that belongs to the Lamiaceae family. Nowadays، the use of biofertilizers is increased in agriculture and their role in increasing the crops production has been demonstrated in many research works (Vessey، 2003; Chen، 2006; Mahfouz & Sharaf- Eldin، 2007). One of the most important visions is sustainable production of enough food plus paying attention to social، economical and environmental aspects. (Gliessman، 1998) stated that the first step to achieve this goal is optimization and improvement of resources use efficiencies. Considering medicinal importance of savory and its role in the food and pharmaceutical industries (Omidbeigi، 2000)، beside the limited nutrient resources and need to increase healthy production through using ecological inputs، this study was designed and conducted aimed to evaluate agroecological characteristics of savory as affected by the application of bio fertilizers، chemical and organic fertilizers under Mashhad conditions.

In order to study the effects of organic، biological and chemical fertilizers on quantitative and qualitative characteristics of summer savory، a split-plot design based on RCBD with three replications was conducted during the growing season of 2012 at the Agricultural Research Station، College of Agriculture، Ferdowsi University of Mashhad، Iran. Different levels of cattle manure (0 and 25 t. ha-1) were assigned to the main plots and different types of bio fertilizers (Nitroxin، containing Azotobacter sp. and Azospirillum sp.، Biophosphor، containing phosphate-solubilizing bacteria (Bacillus sp. and Pseudomonas sp.)، Biosulfur، containing sulfur-solubilizing bacteria (Thiobacillus ssp.)، combination of Nitroxin+Biophosphor+ Biosulfur)، vermicompost (7 t. ha-1)، chemical fertilizers (NPK: 60، 60 and 70 kg. ha-1) and control (no fertilizer) were used in the sub- plots.

According to the results، all studied characteristics including plant height، lateral branches، flowering shoot yield، stem yield، percentage of essential oil and dry matter yield were affected positively by cattle manure. The highest plant height and number of lateral branches resulted from vermicompost and combination of Nitroxin+Biophosphor+Biosulfur، respectively. Biosulfur fertilizer produced the highest dry matter yield، flowering shoot yield and stem yield. Percentage of essential oil was also significantly affected by fertilizer treatments as the most percentage of essential oil was obtained from Nitroxin، vermicompost and combination of Nitroxin+Biophosphor+Biosulfur. A positive and strong correlation was observed between dry mater yield and flowering shoot yield and stem yield، respectively.

The results indicated that application of organic and inoculation of biological fertilizers have positive effects on improvement of qualitative and quantitative traits of summer savory، so it could be considered as an alternative method for healthy production of summer savory.

Water productivity index is one of the main factors in efficient use of water for agricultural products. In this study، the rate of water productivity (WP) in six irrigated tea fields and three rainfed (no irrigation) were assessed by farmer’s management for two years (2009-2010). Yield of each tea field in successive harvests، soil moisture monitoring by gravimetric soil and use of water balance equation was conducted during the growing seasons. Volume of water entered to irrigation system and amount of water reached to surface level were also measured. Tea mean yield in irrigated and rainfed field were 2843 and 1095 Kg. ha-1، respectively. Average of gross irrigation and effective rainfall (WP) and irrigation water productivity (IWP) in the irrigated fields were 4. 39 and 4. 55 kg (made tea) ha-1 mm-1 and average of net WP (actual evaportanspiration) and net IWP was 5. 18 and 6. 61 kg ha-1 mm-1، respectively. Average WP in rainfed tea fields was 3. 4 kg ha-1 for each mm of effective rainfall. The most effective factors on WP reduction in tea fields were improper harvesting operations (un standard plucking) and economic problems. Moreover، improper operation and maintenance and old irrigation systems and unprincipled irrigation scheduling in irrigated tea fields were also effective on WP reduction. Comparing the results of this study with other studies in past، showed that by implementing the proper methods in irrigation management and appropriate agricultural practices can improve water productivity in tea fields.

The purpose of this study is to evaluate financial participation of farmers to reduce the adverse environmental effects of contaminated water by using Contingent Valuation approach and Tobit model by Heckman''s two stage. To achieve the desired goal، 100 questionnaires collected by a random sampling from farmers of Kashaf- rood basin in Mashhad city in 2014. Results showed that variables of age، index 3 (farmers agree with rural and urban sewage inflow into Kashaf-rood river)، total amount annual consumption of chemical pesticides and variables of sex، total area under cultivation، index1 (farmers agree with benefits of preventing soil washing)، index 4 (farmers agree with well being of available soil and water) and index 5 (farmers agree with investments to protect the soil and water)، experience in the use of soil and water conservation practices have a significant and positive and negative impact on farmers'' decisions to participate in financial for reducing the adverse environment a effects of contaminated water، respectively. also، variables of age، type of agricultural activity، under cultivation crops،total amount annual consumption of fertilizer per year، total amount annual consumption of chemical pesticides، index 3 (farmers agree with rural and urban sewage inflow into Kashaf-rood river) and variables of net savings of agriculture، land ownership status، experience in the use of soil and water conservation practices، total area under cultivation، index 4 (farmers agree with well being of available soil and water)، sex have a significant and positive and negative impact on the amount of farmers financial participation for reducing the adverse environmental effects of contaminated water، respectively. Also study results showed that average of maximum amount farmers financial participation for reducing the adverse environmental effects of contaminated water per hectare in the five scenarios to be 134500، 179500، 225500، 271000and354500 rials، respectively. According to the study results،suggestions is presented for reducing the adverse environmental impacts of contaminated water.

One of the strategies for improving the quality of agricultural products is using bio-fertilizers. So in order to study the effects of mycorrhizal fungi، vermicompost and humic acid on growth characteristics and yield of Fennel، an experiment was studied on research farm of agricultural college of Shahrood University. This study was conducted as factorial experiment based on completely randomized block design with three replications. Factors include: mycorrhizal fugi (inoculated with Glomus intraradices and without inoculated)، vermicompost (0،4،8 ton. ha-1) and humic acid (foliar and non-foliar application). Results of this study showed، the main effects of mycorrhizal fungi، vermicompost and humic acid on height، no. of umbels، seed weight per plant، biological and grain yield were significant. Mycorrhizal inoculation increased biological and grain yield compared with control plots about 8. 5 and 20%، respectively. In this study 1000 seed weight significantly was affected by vermicompost and humic acid application. Interaction effects of mycorrhizal fungi، vermicompost on no. of seed per umbel، 1000 seed weight and grain yield was significant. So، the highest 1000 seed weight and grain yield were obtained from combination of mycorrhizal inoculation and 8 ton vermicompost (about 21 and 45 % increase in compare with control). Also the effects of combination of mycorrhizal fungi، vermicompost and humic acid on plant height and biological yield of fennel were significant.

Between of effective factors in agricultural crops production، climatic conditions is an important task from the view of environmental variables. On the other hand the basic in agricultural development is having detailed knowledge of the environmental characteristics in any place and applying specific management. Saffron as the world''s most valuable agricultural and medicinal product is among the plants that has acquired a significant role in the economic and social conditions of arid and semi-arid areas of Southern and Central Khorasan. Thereafter، this study with purpose of climatic conditions evaluation for Saffron cultivation in Torbate Heidariyeh City was conducted. For this reason، climatic data of 10 meteorological stations in the province was selected and with the help of Arc GIS software environment، the modeling and spatial analysis of information was conducted. using of suitable climatic conditions in different growth stages of Saffron، information layers were classified and the value of the maps was determined. Finally for the integrating of information layers using multi-criteria decision-making methods were used based on Analytic Hierarchy Process (AHP)، climatic potential map of Saffron cultivation in Torbate Heidariyeh City was prepared. The results of the study showed that the effect of rainfall، temperature and solar radiation climatic factors، appropriate the different growth stages، in each region is different and from the total 9570. 2071 sq kms area of the Torbate Hidariyeh city according to Saffron cultivation zoning، 6% has a very good quality، 56% of the area has a good quality، 28% has relative conditions for cultivation، 8. 5% has poor and 1. 5% of the area has a quite unsuitable quality for the cultivation of Saffron.

Thyme (Thymus vulgaris L.) is perennial aromatic shrub belonging to the mint family which has anti-spasmodic، antiseptic، carminative، anti-cough، sputum and antioxidant properties. In order to study the effects of drought stress and bio-fertilizer on plant growth، essential oil yield and constituents of thyme plant، an experiment was conducted in a split plot based on randomized complete block design with two replications، at the Research Farm of Zabol University، during growing season of 2012 and 2013. Main plots consisted of irrigation with 30، 50، 70 and 90% field capacity and subplots including plant inoculation with nitroxin، bio-phosphorus and mycorrhiza. Plant traits such as plant height، fresh and dry weight of herb per plant، essential oil percentage، yield and constituents of Thyme were measured. Effects of drought stress، bio-fertilizer and their interactions on all studied traits were significant at the 1% probability level. The highest plant height (35. 09 cm)، fresh and dry weight of herb per plant (103. 52 and 43،27 g. plant-1، respectively) and essential oil yield (0. 350 ml. plant-1) belong to treatment of irrigation with 90% field capacity and nitroxin bio-fertilizer. The maximum essential oil percentage with 0. 413% was obtained by irrigation with 70% field capacity and nitroxin bio-fertilizer. Fresh weight of herb per plant was the most crucial component in determining essential oil yield in Thyme. Plants irrigated with 70% filed capacity gave the highest relative percentage of thymol، which reached 71. 32، 50. 68 and 47. 71% in nitroxin، biophosphorus and mycorrhiza biofertilizer، respectively. This effect was accompanied with decrease in -cymene content. Inoculation with nitroxin bio-fertilizer as compared to other fertilizers could further amend drought stress and improved the plant growth، essential oil percentage and yield and phenolic compound thymol of Thyme. Thus، it appears that in order to achieve sustainable agriculture instead of chemical fertilizers is recommended.

To evaluate the effect of combined use of different soil tillage methods and weed control on cotton yield، a split plot experiment based on randomized complete block design was conducted at the city of Boshruyeh in 2012. Experiment factors were tillage method as Main-plots with three levels، including conventional tillage، no-till system and minimum tillage; and different methods of weed control at 5 levels (the herbicide trifloxysulfuron sodium at 10، 15 and 20 g ha-1، as well as no weeding and hand hoeing) as sub-plots with four replications. The results showed weed density and weeds species were affected by tillage methods significantly. The methods of (no-till or less) conservation tillage than conventional tillage، increased density، narrow leaf weeds in broadleaf weeds while the density decreased. Perennial weeds specially Cynodon dactylon L. were more observed in no tillage treatment but annual weeds for example Setaria spp، Echinochloa crus gali L.، Amaranthus sp. and chenopodium album l. were more dominant in common tillage. In low tillage treatments (Chisel and Disk) there was both annual and perennial weeds. conventional tillage was observed the Most weed density decreased (narrow and broad-leaved) weeds in cotton field in used of dose of 20 g ha envok with Sytvgyt and conservation tillage was next in rank.