f. soroush

In this study, the possibility of growing greenhouse tomato cv. Dafnis with saving water consumption through grafting on different rootstocks was investigated by studying photosynthesis and plant growth. The experiment was carried out in the form of split plots based on completely randomized design in which the main-plot was irrigation levels (irrigation intervals of 3, 6 and 9 days) and the sub-plot consisted of 9 different grafting combinations. After grafting and establishment of tomato plants in greenhouse, the plants were exposed to the irrigation levels for 4 months and all were irrigated up to field capacity. Photosynthesis parameters were measured in four stages and shoot and root dry weights were determined at the end of the experiment. Based on the results, photosynthetic parameters were reduced by the intensity and duration of drought stress. The experimental results showed that the rate of photosynthesis was the same in all grafting combinations 36 days after the start of irrigation levels. However, after 72 days, the rate of photosynthesis in the “Emperador” rootstock was higher than in the control. The chlorophyll fluorescence indices were not sensitive to show the effects of drought stress and the role of rootstocks. Cherry tomato rootstock, in addition to having an extensive root system than the other rootstocks, resulted in more shoot growth at all levels of irrigation, although the least reduction in root weight was observed in the local eggplant rootstock of Yazd. In general, it can be concluded that the photosynthesis in this experiment was more affected by the interaction of environmental factors and grafting and the rootstocks used did not play a significant role in this regard. Furthermore, root and shoot growth traits were more affected by genetic potential of rootstock, and photosynthetic activities of the plant had a minor influence on them.

In the present study, the spatial and temporal changes of climate variables such as pan evaporation (Ep), temperature (T), relative humidity (RH), sunshine duration (SD), wind speed (W) and precipitation (P), as well as their relationship with altitude, were investigated. For this purpose, 68 meteorological stations with 30 years of data (1987-2016) throughout Iran on both seasonal and annual time scales were selected. Trend analysis of climate variables showed that over the past 30 years, most areas of Iran have become warmer and drier although all trends have not been significant. Investigation of the relationship between the trend slope of climate variables and altitude illustrated that there was no significant relationship between them during the study period on the annual time scale (p>0.1). However, in winter, the rate of increase in T (minimum, maximum and mean temperatures) and SD (p<0.1), as well as the rate of decrease in P (p<0.01), was significantly enhanced by increasing the altitude. The increase in mean and maximum T (p<0.1) and SD rates (p<0.001) in summer were significantly lower in the highlands than in the lowlands. In autumn, the trend slopes of minimum and mean T (p<0.05) were negatively correlated with altitude; in addition, the rates of increase in P and RH (p<0.05) in the highlands demonstrated a sharper increase. It seems, therefore, that most changes in climate variables have occurred in both autumn and winter. The results also showed that in winter, the highest rates of increase in Ts were related to the altitude of 1500-2000 m; however, the highest decrease in P belonged to the altitude of 2000-2500 m. In autumn, the highest rates of decrease in minimum and mean Ts had occurred in the altitude of 2000-2500 m; as well, he highest rate of increase in P was observed in the altitudes of both 0-500 m and 2000-2500 m.

The objective of this study was to investigate polyacrylamide (PAM) application and alternate furrow irrigation system on soil erosion. The study was conducted in Dastjerd Research Farm، Bu Ali Sina University، Hamadan، Iran. The experiment was designed as factorial، based on completely randomized design with three replications. Treatments were conventional furrow irrigation without PAM application (FS 0)، conventional furrow irrigation with PAM application (FSP1. 5)، alternate furrow irrigation without PAM application (FAP0)، and alternate furrow irrigation with PAM application (FAP1. 5). The results showed that there is significant difference (p-value <0. 01) in soil losses in alternate furrow irrigation treatment and PAM application (FA P1. 5). The FA P1. 5 treatment، in comparison with FSP0، lead to reduction of soil losses by 98، 98 and 99 percent in the first، second and third irrigations، respectively. Also، the shape of cross section of furrows didn’t have too much change in treatments with PAM application rather than without PAM application treatment. In general، PAM application could cause stability in soil and cross sections of furrows.

Furrow irrigation is one of the oldest methods of irrigation in which soil surface is used to convey and infiltrate water. The furrow geometry data are used for design, evaluation and simulation of furrow irrigation. With furrow geometry data, the furrow infiltration, irrigation efficiency and furrow erosion and sedimentation can be estimated more precisely. Furrow geometry is expressed with some power functions and the coefficients of these functions are used as input for surface irrigation models. In this article, a computer program with Matlab version 7 was written to calculate the furrow cross section functions. The functions are power functions and second order polynomial. To evaluate the model, two cross section data of a furrow irrigation field were used. The model predictions were compared with the two-point method of Elliott and Walker and the results showed that the coefficients of furrow cross section equations obtained by the Elliott and Walker are different with the model output. The results showed that the model is capable to predict the field cross-sectional data with high accuracy. The comparison of coefficient of determinations of the fitted power function and second order polynomial function to the field data showed that both functions can predict the field data closely.

There is a gradual decline in the availability of fresh water to be used for irrigation in Iran. As a consequence, the use of treated wastewater and other unconventional sources of water for landscape irrigation are on the rise in arid and semi arid areas. Irrigation with wastewater changes the soil properties. Hence, a case study was performed to assess the effects of treated wastewater irrigation on nutrient and heavy metal absorption of a turf cover (DALZJ1 variety). In this research, the advanced treated wastewater (TW) of Shahinshahr Wastewater Treatment Plant was used and the effects of different percentages of water and TW (100% water, 50% water and 50% TW, and 100% TW) on three soil textures (sandy loam, loam and clay loam) for a period of 10 months was studied. Statistical design was based on a completely randomized design with factorial arrangement, with three replications. The results indicated that using TW for irrigating turf grass increased plant uptake of N and Cd. The maximum amount of K, Ni, Co and Pb was absorbed by turf grass from soils irrigated with 50% TW. Also, the absorption of P, Fe and Zn was not affected by TW in the irrigation water. Analysis of variance showed that there was no significant difference between soil textures on plant uptake of N, P, K, Cd, Co, Ni, Fe and Zn. The comparison of means showed that there was significant difference in grass Pb content among soil textures. The interaction effects of soil texture and percent TW showed that variation of uptake with increasing TW percentage in irrigation water was not linear and soil texture had no effect on the uptake of elements by this Zoysia variety.