Journal of Arid Biome
Year:2016 | Volume:5 | Issue:2 |Papers Count:9

Salinity is the most important problem in dry lands which cause decreasing of growth. Betacarotene as a non enzymatic antioxidant can scavenge the Reactive Oxygen species. In this study tomato (Lycopersicon esculentum Mill.) seedlings were cultured in MS medium containing 0, 60 and 120 Mm NaCl under 0.6 and 16 mg/L beta carotene treatment in tissue culture conditions. After 3 weeks, the effect of beta carotene on fresh and dry weight, K+/Na+ content, length and the number of roots and proline content were measured. Adding beta-carotene to the culture medium containing salts resulted in the significant increase in the fresh and dry weight and length and number of roots. It also reduced proline and ratio of K+/Na+significantly. Beta-carotene could improve the salt tolerance of tomato by increasing of the root growth. it can be suggested that application of beta carotene may be used for increasing of salt stress in tomato and possibly other useful plants.

Restriction of water resources is one of the main challenges in turf management and the most important tool in reducing of the water requirement in turf land is using drought resistant species. This study was carried out to evaluate some morphological responses of Agropyrondesertorum, Poapratensiscv. Barimpala and Bromusinermis subjected to withholding irrigation. Turf grass seeds were cultured in cylindrical pots in outdoor conditions. Plants were irrigated daily until drainage occurred. After establishment of plants, irrigation was withheld until leaf wilting of the most plants reached to 80%, and then re-watered. After irrigation withholding, leaf wilting of B. inermis, P. pratensisand A. desertorum reached to 80% respectively. Leaf wilting of A. desertorum and P. pratensisdecreased during re-watering and finally became similar to control plants; whereas B. inermiswas completely wilted. Height growth and shoot dry matters were decreased due to drought stress, that this decrease inA. desertorum was less than two other species. Turf quality under drought conditions declined but decreased quality in A. desertorum occurred later. Results of root characteristics shown thatA. desertorum had higher root length and root dry weight than other species. B. inermis, P. pratensis had not significant difference in two traits. Root length in control plants significantly was higher than plants under drought stress. In A. desertorum and P. pratensis root to shoot ratio in grass subjected to drought stress was higher than control grass while the root to shoot ratio in B. inermis did not show significant difference between these treatments.

The implementation of the development plan in a region, without considering of the economic and social issues, not only reaches to the desired results, but also it will have more negative effects. For allocations of resources between the regions, identifying of the position and areas of Endowments development is necessary. there are different ways that essentially the same answers by ranking according to the all indicators.From among the various methods, this study uses the approach of the numerical taxonomy methods that with integrating the different indicators of development show development degree of the Ab-Jagh- Jagh region. The results of this study show that any region has ranks in various factors that are different with total rank. Rating shows that urban, rural and assayer area has first, second and third rank, respectively. Finally, the ratings can be suggested as a basis for region planning.

The effects of using urban wastewater on vegetation and plant diversity indices and surface soil properties were evaluated in combating desertification station of Segzi in east part of Isfahan. Six sites with respect to the planted species (Haloxylon persicum and Nitraria schoberi) and irrigation types (control or no irrigation, water-logged and furrow irrigation methods) were selected with 4 -12 replications. Forty seven surface soil samples were collected and soil texture, organic matter content, acidity, electrical conductivity, calcium and magnesium concentrations, and structure stability were measured. Cover percentage of the species was measured in 47 nested plots. The species richness, diversity and evenness in all replications were calculated by Margalef, Shannon and Simpson indices, respectively. Principal Component Analysis (PCA) and one-way ANOVA were used to interpret the relationships between soil and vegetation properties. Results showed that using urban wastewater significantly increased vegetation cover (about 24.81 to 31.3 %) but plant diversity was not statistically affected. Soil organic matter content and as a consequence of aggregate stability, were significantly increased by irrigating the sites with wastewater. Dispersible clay was decreased (i.e. soil structural stability was increased) as a result of irrigating with wastewater. Therefore, urban wastewater might be used as a source of water for range restoration projects to prevent desertification in natural ecosystems.

Drought forecasting is an important tool for managers for exploitation of the limited resources of soil and water. Recently, Southern Khorasan has become one of the main centers in the country which suffers from severe drought. This study was aimed to assess the capability of CANFIS for drought forecasting of Birjand area through the combination of global climatic signals with rainfall and previous values of Standardized Precipitation Index (SPI). SPI was used to define and monitor the drought event in monthly time scale. In this study, nine global climatic indices were selected for drought simulation. Using stepwise regression and correlation analyses, the signals NINO 1+2, NINO 3, MEI, TSA, AMO and NINO 3.4 were recognized as the effective signals on the drought event in Birjand. In this work, for modeling, 41 years of climatic data records (1970-2010) were collected in which 60%, 15%, and 25% of them were extracted to be used in training, cross validation and testing processes, respectively. The momentum algorithm with Gaussian fuzzy membership function was utilized in network training process. Based on the results from stepwise regression analysis, 12 models were extracted for further processing by CANFIS. However, due to the limitation of CANFIS in the execution of training process with the inputs higher than 5, only 8 models were analyzed using CANFIS. Sensitivity analysis showed that for all models, NINO indices and rainfall variable had the largest impact on network performance. In model No.4, as the model with the lowest error during training and testing processes, NINO 1+2 (t-5) with an average sensitivity of 0.7 showed the highest impact on network performance. After that, the variables rainfall, NINO 1+2 (t) and NINO 3 (t-6) with the average sensitivity of 0.59, 0.28 and 0.28, respectively could have the highest effect on network performance. According to network performance metrics, it was established that the global indices with a time lag represented a better correlation with ENSO. Finally, the fourth model with a combination of the input variables NINO 1+2 (with 5 months of lag and without any lag), monthly rainfall and NINO 3 (with 6 months of lag) showed a correlation coefficient of 0.903 (between observed and simulated SPI) and was selected as the most accurate model for drought forecasting using CANFIS in the climatic region of Birjand.

Land use mapping is the basic tools for administrators and land planners. Severd methods have been proposed for land-use mapping. The latest and most important methods is using remotey sensed data for Land-use mapping. The aim of this study was performance evaluation of the pixelbased classification. (Fuzzy ARTMAP neural network and decision tree Methods) and objectoriented classification methods and using Landsat 8 image of 2013 for land-use mapping of arid and sem-iarid regions of Meimeh Ilam. Different land use classes were difined using training samples comperison of classification results of three different methods of fuzzy ARTMAP neural network, Gini decision tree and Object-oriented Show that the object-oriented approach, has overall accuracy of 95.30 and Kappa coefficient of 90.88, and Gini tree decision and Fuzzy ARTMAP Neural Network methods has overall accuracy of 80.32 and 72.20 and Kappa coefficient of 68.75 and 36.18, respectively thus, object-oriented classification method having a difference in overall accuracy 14.98% and 23.1% and Kappa coefficient of 22.13% and 54.7% has a higher accuracy compared with the Gini decision tree and fuzzy ARTMAP neural network. Map area defined by the three methods of classification, are similar in farmlands, poor rangeland, and urban area. The greatest differences were observed in area of medium rangeland and minimum differences were related to the urban area.

In order to evaluate the effects of drought stress, bio-fertilizers and chemical fertilizer (N+P) treatments on some traits of linseed, include percent of proline, potassium and calcium and the pattern of CGR, a field experiment was conducted as split-plot in RCBD design with three replications at Shahrekord University in 2013.Drought stress at four levels of without stress (with potential of 0.3 atmosphere), light stress (with potential of 3.5 atmosphere), moderate stress (6.5 atmosphere) and severe stress (9.5 atmosphere) as main factors and five fertilizer treatments of control (no ferlilizer), chemical fertilizer (N+P), bio-fertilizer of Azotobarvat 1, Azotobarvar2 and combination of Azotobarvar 1+Azotobarvar 2 as minor factors were used. Results showed that the effects of drought stress, fertilizer and their interaction on the characteristics of proline, calcium and potassium concentrations were significantat 1percent level (P£0.01). The maximum proline (19.24 mg/g dry weight) and potassium (3.10%) obtained under severe drought stress and Azotobarvar 1+ Azotobarvar2 treatments and maximum calcium obtained under severe drought stress and Azotobarvar2 treatments. Analyzing of the trend of crop growth rate the maximum CGR observed at65days after seedling emergence in soil in both control treatment of without stress and chemical fertilizers (N+P).Because ofthe side environmental effects of using chemical fertilizers, using bio-fertilizers of azotobarvar 1, Azotobarvar 2 is recommended.

Estimated daily solar radiation (Rs) based on meteorological parameters measured at surface of the Earth is widely used in various fields. Due to the economic and technical limitations, measurement of this parameter is not possible in all areas. Therefore, daily solar radiation should be estimated based on mathematical models. One of the conventional methods for estimating solar radiation received at the earth surface, is using proposed site-depending models for this purpose in the world. The aim of this study is introducing a new general model to estimate Rs in arid and semiarid regions of Iran. To achieve this goal, climatic data such as daily minimum and maximum air temperatures, in the period of 1970-2010, geographical coordinates (latitude and altitude) of synoptic stations of Isfahan, Kerman, Mashhad, Tabas and Khorobiabanak were collected. Then several global common site – dependent models for Rs estimation were evaluated and, comparing their efficiencies with respect to the statistical indicators, most graceful model was introduced. To provide a general model, between the coefficients of the most profit site - dependent model and characteristics of each location (latitude and altitude) in any station, multiple linear regression relationships were created and analyzed, on the basis of the above calculations, a new general equation was derived.Results showed that the general temperature-dependent model proposed in this study, with an ME of the 0.80, MBE of -0.01, RMSE of 6.50, and mean of 0.690 is the most profit model for estimating of daily solar radiation (Rs) in arid and semi-arid regions of Iran.

In addition to medicinal properties, Agriophyllum minus plant is so important in sand dunes fixation, soil conservation and livestock feeding. According to the germination difficulties, this study investigates seed germination of this plant under cold and halopriming techniques. For this purpose, after applying different cold treatments like control, seed freeze, 20 days continuous cold, alternative cold every 5 days and night cold, the seeds were placed in 3 repeats of 50 seeds in germinator. This experiment was also done with 4 concentration levels of KNO3 (0, 50, 100 and 200 mmol) and 4 time levels (0, 24, 48, 72 hours) with 3 replications using factorial experiments in the form of completely randomizeddesign. Results showed that the cold treatment had a significant effect on germination percentage, daily germination mean, germination index, time of germination mean (p<0.01) and seed vigor index in 5% level. Night cold treatment had a significant increase in terms of germination percentage, daily germination mean, seed vigor index and germination index, compared to other treatments. The results also demonstrated that KNO3 concentration effect was significant on germination speed and time of germination mean (p<0.05). Therefore, applying cold treatment, especially night cold, as a new approach to improve germination quality of this medicinal plant, can help to increase production, development and restoration of destroyed arid lands, soil conservation and, sand dunes fixation and, finally sustainable development.