فصلنامه حفاظت منابع آب و خاک
سال ششم شماره 1 (پیاپی 21، پاییز 1395)

To study the effect of deficit irrigation, partial irrigation and superabsorbent polymer on yield and yield components of corn, a field experiment was carried out in factorial split plot arrangement using randomized complete block design with four replications at Research Farm of Islamic Azad University, Karaj branch, Iran in 2014-2015 growing year. Deficit irrigation with three levels including irrigation with 100, 75 and 50 percent crop water requirement, furrow irrigation methods with two levels including partial irrigation (fixed alternate furrow) and conventional furrow irrigation that were located in the main plots and superabsorbent polymer with two levels including non-use superabsorbent polymer and used of superabsorbent (30kg/ha) that were located in the sub plots. Grains yield in partial irrigation method as compared to conventional furrow irrigation in condition of 100% crop water requirement decreased (38.5%). However difference of grain yield between fixed alternate furrow irrigation and conventional furrow irrigation in condition of irrigation with 75% and 50% crop water requirement was not significant. The use of superabsorbent saved irrigation water consumption by 13.4% during the growth period. According to a 26% reduction in the amount of irrigation water during the growing season in partial irrigation method, for achieve of corn grain yield in condition of irrigation with 75% and 50% crop water requirement can be used from partial irrigation method (alternate furrow irrigation) instead of conventional furrow irrigation method in the studied area. Also, along with partial irrigation method, to raise the water use efficiency can be used superabsorbent.

In order to identify sensitivity of different potato genotypes to water stress, a research was carried out as a factorial experiment in a randomized complete block design with three replications in Karaj in 2014 and 2015. Potato genotypes at eleven levels (Agria, Caesar, Savalan, Sante, Marfona, Milva, Picasso, Hermes, Jelli, 397081-1, 397069-2) and irrigation treatments in two levels (stress and control) are conducted. Tape irrigation was done normally and in the early stages of tuber production, watering for stress plots was disconnected and control plots were irrigated in a normal way, after reaching to ninety percent of the soil moisture deficit, irrigation was done again until the soil moisture reached field capacity and irrigation was done normally up to the end of growing season. Combined analysis of data for two years showed a reduction of biological yield, healthy tuber fresh weight, marketable healthy tuber fresh weight, LAIM, dry weight of LAIM, evapotranspiration and water usage in genotypes under the stress compared to the control. WP based on fresh weight of healthy tubers and fresh weight of marketable healthy tubers reduced or showed a tendency to reduction in most of genotypes under the stress. WUE based on the healthy tuber yield and marketable healthy tuber yield decreased under the water stress compared to the control in all genotypes except for 397069-2. The most amount of WP based on fresh weight of the marketable healthy yield was observed in 397069-2, respectively (5.41) and (5) kg/m3 in two years under the stress. Based on results of this experiment, doing of additional researches in order to achieve suitable potato genotypes for planting in actual deficit water conditions of our country according to diversity of planting season, place, climate, quality of seed potato, experts and etc. are recommended.

Considering the limited access to fresh water resources and intense plant respiration and high evapotranspiration in deserts and arid regions, subsurface irrigation seems to be the most appropriate method for cultivation. The aim of this study was finding a proper subsurface irrigation to supply moisture for plant roots using bio-composite water pipes to supply water for panicum. Experimental design was factorial experiment conducted based on completely randomized block design with three replications in the Faculty of Agriculture in Tarbiat Modarres University in 2015. Main factors included subsurface irrigation using three types of bio-composite water pipes manufactured P3, P8, P9, subsurface irrigation using subsurface porous clay capsules and flood irrigation (control treatment). Secondary factors included three drought stress levels of 25, 50, and 100% of soil field capacity (FC). Results showed that, subsurface irrigation treatment using water pipe P8 and drought stress level of 25%, and FC decrease for 12.68%, was the lowest water consumption in irrigation. In addition, in subsurface irrigation, height, wet and dry weights were significantly different at %1 level compared to flood irrigation. Therefore, with regard to responsiveness of panicum water demand to subsurface irrigation using bio-composite water pipes, and considering the results of this research using subsurface irrigation by bio-composite water pipes, it is recommended to optimize water consumption for urban areas located in arid and semi-arid regions.

Climatic classification of geographical areas from the distant past has been done. With the difference that in the past the traditional methods and GIS technology today with the advancement of modern methods are used. As well as the use of multiple climatic parameters in traditional methods alone would not be cardiac regions climate reality. Therefore, in recent years, researchers have tried to use the number of parameters affecting climate and more modern methods, real climate regions of the video provider. The purpose of this article the climatic regionalization of southern Khorasan Province with the method of factor analysis and cluster and Spatial Autocorrelation and more climatic elements in determining the type of weather for the area to be incorporated.To improve the results of climatic regionalization of synoptic meteorological stations facts and climatological was used. For this purpose a matrix 34 * 11 Includes 7 synoptic station and 4 climatological station. The results of this analysis showed that climate affected province of 6 factors in order of importance are, Temp (temperature), humidity of the atmosphere, windy- dust, Frost, rainy, sunny (radiation). The exercise component of about 96.5 percent of the interpretation of climatological behaviour. Cluster analysis on the factors mentioned there are 6 region of air and water in the province showed. Semi-warm and dry temperate zone, Hot and arid area, Hot and dry semi-desert area, Cold and semi-arid mountainous area, Wilderness area, Hot and dry desert area

Water and food security are the key challenges under climate change as both are highly affected by continuously changing climatic patterns. In this study, attempts have been made to investigate the effects of climate change on length of growing season and water use of sugarcane under RCP scenarios in 4 stations of Khuzestan province, southwest of Iran, namely Abadan, Ahvaz, Bostan and Dezful. The outputs of EC-EARTH global climate model data which were dynamically downscaled by Swedish Meteorological and Hydrological Institute (SMHI) under RCP 8.5 and 4.5 scenarios were used as future projections. The climatic observed data of 4 study stations were collected and used to calibrate the model downscaled outputs. The changes of precipitation, crop evapotranspiration and length of growing period of sugarcane were worked out. The results showed that except for Dezful station, growing season rainfall would increase comparing to climatic normal. Besides, the length of growing season under RCP8.5 scenario would decrease significantly in all stations. Future trend of evapotranspiration changes were non-significant and less than 5%

Water repellency increases soil infiltration opportunity time. Also soil hydraulic properties affects by soil water repellency. The main objective of this study was to compare the hydraulic properties of soils under different water repellency levels. Therefore, Three levels of water repellency (zero, weak and strong) were artificially created in a silty clay loam soil by adding urban sewage sludge (S0=0:100; S50=50:50 and S80=80:20 sludge weight: soil ratio). Soil water retention curve and water repellency were determined using sand box and pressure plate apparatus and water drop penetration time (WDPT) method, respectively. Van Genuchtens parameters (n, α, m, θs, θr) were determined using RETC software. The results showed that an addition of urban sewage sludge to soils led to an increased WDPT (61 and 25 times) in the water repellency Soils (S80 and S50) .water content corresponds to matric potentials has changed with increasing soil water repellency, also soil water retention curve has changed to biomodal curve in the repellent soils. It shows that the Van Genuchtens parameters affected by water repellency. Also, adding of urban sewage sludge on the soil hydraulic conductivity was significant (P ≤0.0001) and resulted in a decreased 33.80-46.20% in in soil hydrophobicity.

In the present study, the effect of different levels of salinity on germination and growth indices Quinoa (Chenopodium quinoa Willd.) in two types of cultivars Sajama and Titicaca under 5 salinity levels (0, 15, 30, 45 and 60 percent of the mixing sea water and tap water). This experiment laboratory was conducted as a factorial experiment in the basis of randomize complete design with 3 replications with two factors at department of irrigation, Gorgan University of Agricultural Sciences and Natural Resources in 2016. Measured characteristics were germination velocity, vigor index, radicle and plumule length, seedling growth fresh and dry weight and mean germination time. According to the results, different levels of salt stress had significant effects on germination velocity, radicle length (p ≤ 0.01) and plumule length, seedling growth fresh weight (p ≤ 0.05) while the effect of cultivar type was significant on vigor index, radicle length, seedling growth fresh weight and mean germination time (p ≤ 0.01). The interaction between salinity and cultivar type had significant effect on germination velocity, mean germination time, plumule length, seedling growth dry weight (p ≤ 0.05) and vigor index, radicle length (p ≤ 0.01). The results showed that with increase in salinity level, all measured characteristics were significantly decreased. According to the results, the germination stage of Quinoa has a good tolerance to elevated levels of salinity and it seems that a good stand establishment in saline soils and water conditions could be insured, if proper management is exerted in farms.

Soil erosion has been known as a serious environmental problem. Drainage density is one of the most important geomorphological parameter that is used as an index for stream situation, rainfall, runoff, infiltration capacity, topography evolution and erosion. With knowledge about the relationship between characteristic basin with drainage density, we can predict the other properties of basin. The aim of this study was survey of relationship between soil and geology characteristics with drainage density. First, basic information was collected and watersheds boundary was found on topography map. Land component and geology map was prepared and in each land component was determined locations for profile. After field checking at determined location dug profiles and determine physicochemical parameters of soils. Drainage density was calculated using ARC GIS software. Finally using Excel 2013 through charting, the relation between soil characteristics with drainage density was determined and correlation of these factors were analyzed using SPSS software. Results showed that the relationship between soil properties and drainage density in formation and land component is significant at 95 percent level. Also results indicated that drainage density is affected by lithology of formation, slope, and some properties of soil such as TNV, silt, organic carbon and coefficient of erosibility. The maximum of drainage density belonged to quaternary formation without proper plant cover and NGM formation ad minimum of drainage density belonged to TUF and lime formation. Therefore, to some extent, with using of drainage density we can predict soil and geology properties.

Sediment transport has always affected the river and civil structures and the lack of knowledge about its exact amount causes high damages. Therefore, it is very important to properly estimate the sediment load in rivers in terms of sediment, erosion and flood control. This study used two new data mining methods including M5 model tree and support vector regression comparing with the classic method of sediment rating curve to estimate the suspended sediment load in Aharchay River. To assess the performance of the used methods, three criteria including the correlation coefficient, root mean square error and mean absolute error were used. Analyzing the sensitivity of models to the input variables, it was found that the variable of flow discharge in the current month had the greatest effect on the amount of suspended sediment load. The results showed the high accuracy of new data mining methods in comparison with the sediment rating curve. Although, both considered data mining methods had more accuracy and less error compared to the conventional sediment rating curve, given the simple understandable linear relationships provided by the M5 model tree, this method is recommended for similar cases.

The analysis uncertainty of hydrological models and identify the statistical properties them basis of existing relationships between of the model parameters and inputs is numerous of the most important hydrological modeling. In this context one of the known methods for modeling the water balance at the catchements scale is Dynamic water balance model (DWB) that By Zhang et al. (2008) developed. In this study, the model calibration and uncertainty assessment in the Andrab and Farvbrman catchments from the Kalshvr River branches (Nishapur catchment) respectively at the zarandand and Eyshabad hydrometery stations, located in semi-arid regions by using Generalized likelihood uncertainty estimation (GLUE) method was studied. The results indicated that in terms of the ability to identify, Between four parameters of the model, Retention efficacy parameter (ω_1) and basin water storage capacity (s_max [mm]) in the calibration process was less of the ability to identify (The specific domain ptimum for their can not be found) and uncertainty in the runoff simulated by the model, have a greater role. In this direction, the efficacy parameter evapotranspiration (ω_2) and the gradual flow (d), resistant behavior of the errors in the runoff observation and are so-called conservative. Evaluation of uncertainty runoff simulated showed that in general, GLUE method is well managed that it calibrate amount of runoff from case study, so that more of the runoff data recorded (over 55%) in the range of 95 percent.