مجله پژوهش آب در کشاورزی
سال سی و ششم شماره 1 (بهار 1401)

In this study, salinity tolerance of five sorghum varieties (Speedfeed, Kimia, Payam, Sepideh, and Pegah) was studied using five irrigation water salinity levels (non-saline water, 4, 8, 12 and 16 dS/m) in the greenhouse. The statistical design was a factorial randomized complete block design with 25 treatments and four replications. The studied traits included plant height, leaf area, dry weight of roots and shoots, ratio of dry weight of roots to shoots, leaf chlorophyll index, concentration of sodium, chlorine and potassium in leaves and roots. The effect of variety and the effect of salinity stress on the mean of all measured traits were significant (P <0.01). At salinities of 4, 8, 12, and 16 dS/m, shoot dry weight was lower than the control (5.72 g/plant) by16.2%, 35.1%, 55.7%, and 69.4%, weight of dried roots lost 26.6%, 53%, 72% and 82%, compared to the control (5 g/plant), and the leaf area of the plants decreased by 29.4%, 58.3%, 75.5%, and 86.3% compared to the control, respectively. There was a negative correlation between chlorine and leaf sodium concentrations with shoot dry weight. Fisher stress sensitivity coefficient was used to evaluate the salinity sensitivity of cultivars based on shoot dry weight. Based on this coefficient, Speedfeed variety had the lowest salinity sensitivity coefficient (0.73) and Pegah cultivar had the highest (1.21). Regression was determined between different salinity levels with shoot dry weight for each cultivar. Accordingly, Speedfed, Kimia, Payam, Sepideh, and Pegah cultivars suffered a 50% reduction in shoot dry weight in salinities of 13.89, 12.95, 9.73, 9.62 and 9.50 dS/m. Based on the results, Speedfeed variety had a higher salinity tolerance than other cultivars and is recommended for cultivation in saline soil and water conditions.

The aim of this study was to estimate the actual evapotranspiration of wheat using Surface Energy Balance Algorithm for Land (SEBAL) and compare with data measured by lysimeters in two study sites in Tabriz and Karaj during three growing seasons (1396-1399). Values of actual evapotranspiration of wheat during the growing seasons were calculated by two methods a) using Landsat 8 satellite data through SEBAL, and b) using drained lysimeter data. Considering that evapotranspiration in SEBAL is in actual conditions and lysimeters provide evapotranspiration in potential conditions (standard situation without any limitation), to reduce errors, remote sensing data were used for pixels that had moisture conditions similar to standard lysimeters conditions. Comparison of actual evapotranspiration obtained from SEBAL and lysimeter in both sites showed relatively good correlation. The coefficients of determination (R2) were 0.73 and 0.65 in, respectively, Karaj and Tabriz sites. In addition, using statistical parameters such as NRMSE, RMSE, MAE, and MBE showed that SEBAL actual evapotranspiration data and lysimeteric data were, relatively, in agreement in the two study sites. However, in most cases, evapotranspiration values by SEBAL were greater than values measured by the lysimeter. In general, considering the advantages of the SEBAL, it is suggested this technology be used to estimate the actual evapotranspiration of wheat in large-scale areas.

Despite Gilan Province being a rainy region in Iran, inappropriate distribution of rainfall during the growing season has a negative impact on the growth of crops, including borage. This study was conducted to determine the proper irrigation regime for borage at different stages of growth. For this purpose, fifteen field experiments, based on 15 combinations obtained from the Central Composite Design, were conducted using high and low levels of treatments including water requirement (without irrigation (I1) and full water supply (I2)), two growth stages (stem elongation (D1), stem elongation and flowering (D2)), and two years with different rainfall (drought (Y1) and wet season (Y2)). The experiments were performed in Giulan Agricultural and Natural Resources Research and Education Center located in Rasht. Irrigation and stage of growth had the most and the least effects on borage yield and growth parameters, respectively. Dry season increased the grain yield, oil yield and oil percentage, while other parameters reached their maximum value in wet year. The value of 1000-seed weight for D2 was equal to 18.9 g, and the values of dried flower yield, fresh flower yield, seed yield, and economic yield are equal to 468, 858, 486 and 983 kg.ha-1, respectively. Oil yield and oil percentage for D2 were equal to 160 kg.ha-1 and 33.5%, respectively. Considering the optimal levels for all parameters based on the interpolation of factor values in the central composite design, if the percentage and yield of oil is less important than the other parameters, it is necessary to provide 88% of irrigation water for the stem and flowering stages in the wet season. In order to achieve maximum yield and oil content, full supply of irrigation needs in dry season and in the stem stage should be considered.

Salinity is one of the most important abiotic stresses that has many negative effects on plant growth. To investigate the effect of salinity water irrigation stress on morphological and physiological characteristics of sorghum, an experiment was conducted in a randomized complete block design with 3 replications in soil columns located in the Agricultural and Natural Resources Research Center of Mazandaran Province. The number of experimental columns was 15 and the duration of the experiment was 56 days. Salinity treatments included well water (control) (S1=0.995 dSm-1), Mix seawater and well water in proportions 1/4 (S2=4.680 dSm-1), 2/4 (S3=8.130 dSm-1), 3/4 (S4=13.710 dSm-1) and seawater (S5=15.910 dSm-1). In this study, dry and wet weight of shoots, seeds and roots, diameter and height of main stem, leaf area index, leaf area, harvest index, biological yield and resistance indices of sorghum were measured. The results of analysis of variance showed that the effect of salinity on all measured traits was significant. Increasing the salinity level of irrigation water from control (S1) to treatment (S5) caused a significant decrease at the rate of 1 to 70% in all measured traits except harvest index and root to stem ratio. Also the results of this study showed that the best salinity level to achieve maximum yield in sorghum (Equivalent to 13/218 g) is salinity level (S1). Regarding resistance indices, S1 treatment had higher k/Na and Ca/Na ratios than other treatments, which were 6.67 and 1.4, respectively. Also, the results of comparing the mean of traits between different treatments showed that there were no significant differences between S3 and S4 treatments in traits such as grain yield, straw yield, plant height, leaf area, harvest index, dry weight of root and resistance indices that Up to 3: 1 ratio, seawater to well water can be used to grow sorghum. Also, the relative yield of sorghum to salinity did not decrease by about 3.65 dS /m, which was considered as the tolerance threshold of this plant. But after increasing the salinity of soil saturated extract, plant yield decreased and at salinity of about 15 dS /m was halved. The slope of the sorghum yield reduction line at this stage was calculated to be 3% dS / m.

In this research, the effect of salinity stress on the amount of evapotranspiration components of maize were investigated in mini-lysimeters (in the initial, development, mid, and late growth stages). Salinity treatments were applied by water with EC of 0.5(S0), 2.1(S1), 3.5(S2), and 5.7(S3) dS.m-1. The experiment was performed as factorial and in a completely randomized design. For the whole growth period and for S0 to S3 treatments, the values of evapotranspiration, transpiration, and evaporation were measured in the range of 420-320, 285-124, and 135-196 mm, respectively. The share of crop transpiration (T/ETc) decreased by 29% while the share of evaporation (E/ETc) increased by the same value. From S0 to S3 treatment, the values of evapotranspiration, transpiration and evaporation were measured in the range of 420-320, 1 / 285-3 / 124 and 134-7 / 195.9 mm (in the whole growth period), respectively.From S0 to S3 treatments, the values of evapotranspiration, transpiration and evaporation were measured in the range of 79-72, 19-10 and 61-62 mm (initial stage), 202-150, 150-71, and 51-79 mm (development stage), 124-84, 110-39, and 14-45 mm (mid stage), and 15-14, 6-4, and 9-10 mm (the late stage). The shares of crop transpiration decreased in the order of the developmental, mid, initial, and the late stages, while the decreasing order for the shares of evaporation was related to the initial, developmental, mid, and late stages, respectively. The dry biomass yield decreased by salinity stress, and its amount in treatments S0, S1, S2, and S3 was as 12942, 12168, 10872, and 8928 kg.ha-1, respectively. Stress coefficients of evapotranspiration (KS), transpiration (KS-T), and evaporation (KS-E) were calculated in the range of 1-0.76, 1-0.43, and 1-1.45, respectively. The results showed that for 1 dS.m-1 increase in water salinity, the amounts of relative evapotranspiration and relative transpiration decreased by 4.7% and 11.1%, respectively, and the amount of relative evaporation increased by 9%. The results showed that the transpiration component decreased with a greater slope, relative to the evapotranspiration.

Surface irrigation systems have been widely used in in arid and semi-arid regions of the world, but inappropriate design and management has led to high water losses and reduced water productivity. The objective of this research was to investigate the effect of plastic mulch placements in furrow irrigation on soil water distribution and water productivity under fodder corn production. Field experiments were carried out in Karaj in 2018. Four different treatments were considered in terms of plastic mulch placements including mulch on the ridge (R), mulch on the furrow bed (F), mulch on the ridges and the furrow bed (FR), and a treatment without mulch or control treatment (C). In order to measure water content, soil samples were taken one day before and three days after each specific irrigation event with 5 days intervals from four points (at 0-25 cm and 25-50 cm under the ridges and furrows) for all treatments. The mean values of volumetric water content during the growing season for the FR, F, R and C treatments were 24.8, 23.8, 18.0 and 17.1 percent, respectively. The results indicated that plastic mulch had substantial impact on retaining the soil moisture by reducing evaporation from the soil surface and the treatments with plastic mulch on the bed of the furrow (FR, F) had the highest soil moisture in comparison to the other treatments. Water productivity for dry matter of the FR, F, R and C treatments was 4.5, 4.4, 3.6, and 3.0 kg/m3, and for fresh matter of the FR, F, R and C treatments was 7.6, 7.4, 5.7, and 4.7 kg/m3, respectively. Based on the results, using plastic mulch on the furrow bed is recommended in order to reduce water loss and increase water productivity in furrow irrigation. Considering the effect of plastic mulch in maintaining soil water content, it is also recommended to utilize this method with the deficit irrigation method. Economic aspects should be taken into consideration in the future research on this topic.

Water and land were two important factors of production in Iran and irrigation water depended on type of ownership. According to the differences of geographical location and social status of Iranian Plateau, the situation of water and land ownership changed in different areas. Climate, social status, and strategic situation of Mazandaran Province affected the model of land and water ownership and gave them characteristics. We intended to answer these questions in this study: What institution built Mazandaran water facilities? How was the situation of their ownership? What effect did the production system and land ownership have on the water ownership and Mazandaran irrigation situation? The findings of this study showed that the water ownership right was directly affected by landholding system and the relationship between landowner and farmer. This right was under the supervision of religion and traditions of Iran in Qajar era. The ownership of Mazandaran important rivers was in a form of Khaliseh (governmental) and water delivery and distribution was done by the villagers (Mirabi) from the Khaliseh villages. Climate and soil fertility were important factors in growing types of crops and in making water facilities such as Ab-bandan (water storage ponds) and Qanat, which were made by the people. Government mostly monitored water resources during the water distribution and building dam on them. Also, government benefited from Khalise right. This issue was examined historically and the data are provided from library documentation and archives. An explanatory method of describing and analyzing the subject has been used in this study.