مجله تحقیقات آب و خاک ایران
سال پنجاه و چهارم شماره 1 (پیاپی 85، فروردین 1402)

In order to investigate the effect of growth-promoting bacteria inoculation on soil characteristics, nutrients uptake and growth of bell pepper, a randomized complete block design with five species of growth-promoting bacteria (Bacillus subtilis, Azospirillum lipoferum, Azotobacter chroococcum, Enterobacter cloacae and Pseudomonas putida) with three repetitions was carried out in Isfahan Wheat Field greenhouse in 2021. The chemical and biological properties of the soil, NPK uptake, and the growth and yield characteristics were investigated. The results showed that the addition of growth-promoting bacteria effects on some soil characteristics and bell pepper growth. The treatments showed a significant difference in terms of total nitrogen, phosphorus and potassium available in soil, respiration and rhizospheric microbial population, NK uptake, yield and fruit number (p≤0.01). The best soil nitrogen content (0.44%), nitrogen uptake (28.8 g.m-2) and shoot dry weight (0.565 g.m-2) were observed in Azotobacter chroococcum treatment. The highest rhizospheric microbial population (7.6×106 cfu.g-1) and R/S ratio was 47.9 in Enterobacter cloacae treatment. Fresh weight and dry weight of plant shoot were higher in Azospirillum lipoferum treatment, which was not significantly different from Azotobacter chroococcum and Enterobacter cloacae treatments. In the treatment of Enterobacter cloacae, the yield (18.8 kg.m-2) and the fruits number (65.8/m2) were higher. The application of Enterobacter cloacae, Azotobacter chroococcum and Azospirillum lipoferum bacteria was higher effect on the growth indicators of pepper, which can be recommended for the use of these bacteria as biofertilizers in bell pepper cultivation.

Reference evapotranspiration as an important indicator of demand for air evaporation is an important factor for climatic and hydrological studies. Due to the occurrence of climate change and the occurrence of large fluctuations in precipitation and the occurrence of mild to severe droughts, it is important to study the evapotranspiration changes. In this study, to investigate the temporal-spatial changes of trend and change point in the reference evapotranspiration time series for different seasons in Mazandaran province, 40 years data (1981-2020) from satellite networks (with a resolution of about 5 km) were used. Non-parametric Mann-Kendall, Sen's slope, Pettitt's test (Non-Parametric Rank Test) and quantile regression were used to investigate the changes in the trend and to present the range of fracture point changes in the evapotranspiration. The correlation coefficient between network evaporation-transpiration data and ground station data was estimated to be more than 0.9 in most of the stations and the average value of BIAS was 0.24. The results of Pettitt's test showed the time of sudden changes in reference evapotranspiration in spring, autumn and winter seasons in 2013, 2007-2010 and 1999, respectively, in most cases. Very high values of evapotranspiration increased in spring in the eastern half, in summer in the northern half and in winter in the southern and western strips (with a seasonal slope percentage of 45, 75 and 120 percent, respectively), but they decreased in autumn in the north of the province (with a slope of -45 percent). In general, significantly increasing slope rates for high values of evapotranspiration were higher than average. A significant increase in high amounts of evapotranspiration, especially in the dry season, will reduce water resources and disrupt the agricultural sector. Therefore, scientific and practical methods for managing reference evapotranspiration in the province should be considered.

Soil compaction and formation of plow pan in Iranian agricultural soils became a serious problem, which threatens regional productivity. The formation of plow pan due to the long-term use of tillage tools at a constant depth, is a common consequence of conventional tillage, which limits crop growth. In order to prove the existence of plow pan and its effect on physical and chemical soil characteristics, 32 soil profiles (eight soil profiles in each region) were analyzed in Qazvin, Golestan, Markazi and Khuzestan provinces. In all four regions and in 70% of the soils, plow pan with an average thickness of 24 cm was observed at 16 to 64 cm below the surface. Total porosity and the amount of bulk density showed respectively about 7-19% decrease and 5-14% increase in the plow pan compared to other horizons. The depth of the formation of this layer and its vertical expansion as well as the intensity of compaction in the soils of the studied areas have been different. The presence of the plow pan (except for Abyek region of Qazvin) had caused the accumulation of 14 to 40% of dissolved salts and the creation of a relatively saline layer under the surface horizon (Ap). The most important reason for the high compaction of the plow pan in the Gonbad agricultural area compared to the other three areas, was the high average percentage of silt (about 60%) in this area. In addition to the effect of soil texture, the predominance of submerged irrigation, despite the aridity of the climate, intensifies the compaction and resistance to root penetration especially in the agricultural areas of Golestan, Khuzestan and Markazi provinces, because annual plowing at constant depths along with heavy irrigation with a large volume of water leads to the eluviation of clay and silt particles from the surface and illuviation in depth.

The presence of salts in irrigation water and high evapotranspiration rate in Sistan and Baluchestan cause the accumulation of salt in the soil and as a result increases the osmotic force in soil. One method for crop irrigation planning is the use of Idso crop water stress index (CWSI) and Moran water deficit index (WDI). In order to investigate the effect of irrigation water salinity on CWSI and WDI and also wheat irrigation planning, an experiment was performed with three different irrigation water quality in Iranshahr, through the 1398-99 crop year. The experiment was performed as a randomized complete block design with 4 replications and 3 treatments including (1) irrigation water with salinity of 0.7, (2) irrigation water with salinity of 2.5 and (3) irrigation water with salinity of 5.2 dSm-1. The results showed that irrigation water with salinity of 0.7 and 2.5 dSm-1 have no significant difference in terms of yield and water use efficiency. However, the use of irrigation water with a salinity of 5.2 dSm-1 caused a significant reduction in yield and water use efficiency at a 1% level. Moreover, the salinity of irrigation water increased the upper baseline in the Idso diagram and the upper side of the proposed trapezoid of Moran, but it had no effect on the baseline (plant transpiration limit under standard conditions). As a result, according to the definition of CWSI and WDI indices, these two indices decreased by 19% and 22%, respectively compared to the control treatment. The average optimal CWSI and WDI in the first (non-saline) treatment were 0.39 and 0.38, respectively, and they were 0.33 and 0.32 in the very saline treatment, respectively. This showed a decreasing trend of irrigation frequency with increasing salinity of irrigation water.

Side weirs are types of hydraulic structures, which are used for different purposes in water transmission systems. In most of the construction operations of irrigation channels and water transfer, based on the topographic conditions of the land, the bottom of the channels is sloped. The purpose of this research is to numerically investigate the changes in the slope of the bottom bed and evaluate the performance of the side weirs in flood conditions and supercritical and subcritical flow regimes. To simulate the flow, CFD method and FLOW-3D® software and RNG turbulence model were used. By examining the surface profile of the flow passing through the weirs at different bed slopes, it was observed that in a fixed slope, in the subcritical flow regime, the surface profile trend is increasing from the beginning to the end of the weir, and decreasing in the supercritical flow regime. As the slope of the main channel bed increases, the level of flow passing over the weir decreases. On average, by changing the regime from subcritical to supercritical, the weir efficiency decreased by 11.21%. Increasing the bed slope decreased the weir efficiency and discharge coefficient in the subcritical flow regime up to 14.54% and in the supercritical flow regime up to 9.26%. The increase in discharge coefficient with the increase of the weir height varied between 4.6 and 7.8 percent. With the increase of the slope of the channel bed, the velocity along the weir in the subcritical and supercritical flow regimes increased by 10.88 and 6.17%, respectively, and the transverse velocity decreased by 22.23 and 4.8 percent, respectively for the subcritical and supercritical flow regimes.

The present research performed to investigate soil evolution in soils developed on sedimentary and igneous parent materials, northern Kerman. Four representative pedons were selected. Physicochemical properties and Micromorphological features investigated in soil samples. The principal oxides content measured using ICP-OES. Color, clay accumulation, Fe content, and geochemical indices were used to assess soil development in the studied pedons. Studied profiles classified in Aridisols order and Calcite, Gypsic and Argillic horizons were dominant. Mean of pedogenic, free, crystalline, and active Fe contents were determined as 9.4, 0.5, 8.8 g/kg and 0.06, respectively. The values of clay and Fe accumulation indices were obtained 17 (in pedon 3) to 76.5 (in pedon 2) and 24344 (in pedon 2) to 2788 (in pedon 3), respectively. The results showed the correlation between Fe contents and color indices at the 99% level. The mean weight of principal oxides noticeably increased in pedons 1 and 3 compared to other studied pedons. All of geochemical indices, except WIP, showed higher weathering in pedons 1 and 3.The results of color, Fe oxides and clay accumulation and CIW, CIA, PWI, V, PIA, STI and R geochemistry indices demonstrated higher evolution of pedon 3 compared to other studied soils. No significant difference in development rate reated to parent materials change was found. Likely, various evolution of studied pedons was due to intractions among geochemical indices and soil-forming factors and processes.

Hydraulic conductivity is one of the most important physical properties of soil, and knowing it plays a vital role in investigating the transport of solutes and pollutants in porous environments such as soil. This study aims to obtain saturated hydraulic conductivity pedotransfer functions (PTFs) using soil properties and satellite images. In this regard, the hydraulic conductivity of soil saturation was performed using the Inversed augerhole method in a part of the southwestern lands of Khuzestan province at 50 points. Then, at these points, surface samples of the soil were taken and soil properties such as soil texture, electrical conductivity, soil organic carbon, and saturated moisture were determined in the laboratory. In the next step, the indices of Sentinel-2 satellite images were calculated in three categories of soil, vegetation, and moisture indices and 11 PTFs, (PTF1-PTF11) for saturated hydraulic conductivity were obtained in four stages by combining soil properties and these indices. Finally, the spatial distribution of saturated soil hydraulic conductivity was obtained using the random forest model. The results of the modeling of PTFs of saturated hydraulic conductivity showed that among the 11 models with which PTFs of hydraulic conductivity were performed, the combination of three vegetation indices with soil-found early properties was the most effective for estimating the saturated hydraulic conductivity (PTF7). The values of R2, RMSE and MAE for this case were equal to 0.83, 0.40 and 0.166 respectively. Finally, the spatial distribution of saturated hydraulic conductivity using the Random Forest model showed that this model performs the spatial distribution of saturated soil hydraulic conductivity of soil well. Based on the obtained results, it can be found that the combination of soil properties with the indices obtained from the Sentinel-2 satellite images, creates PTFs of saturated hydraulic conductivity of the soil with very high accuracy.

Humic acid is an organic compound that can improve the physical, chemical and biological properties of soil. In addition, it plays an important role in increasing plant growth and yield. This composition can be extracted from various sources that are rich in organic materials such as composts, coal, humus materials and soil. In order to know the spectral and structural characteristics of this compound, humic acid was extracted from different organic sources in 2021. The amounts of carbon, oxygen, hydrogen and nitrogen elements in the extracted humic acids were determined by elemental analyzer, functional groups by FTIR and the spectrophotometric absorption ratios of E3/E5 and E4/E6 were determined by spectrophotometer in Department of Soil Science and Engineering laboratory, Razi University, Kermanshah. The lowest H/C ratio in the extracted humic acids was observed from municipal waste compost (1.05) and vermicompost (1.09), the highest O/C ratio was in humic acid extracted from municipal waste compost (0.70) and vermicompost (0.59), and the lowest C/N ratio was in humic acid of chicken manure (11.84). According to the results of FTIR analysis, the strongest absorption bands were observed at 3400 cm-1, 2900-3000 cm-1, 1600- 1700 cm-1 and 1000-1100 cm-1. The highest ratio of E3/E5 was found in humic acid extracted from chicken manure (12.81) and sheep manure (10.61) and the lowest amount was observed in municipal waste compost (2.00). The highest ratio of E4/E6 was obtained in humic acid extracted from chicken manure (7.31) and the lowest amount of E4/E6 was observed in humic acid obtained from municipal waste compost (4.70).

In order to evaluate the effects of soil and foliar applications of Zargrain organic fertilizer on water-use efficiency, yield and yield components of wheat under drought conditions, two separate factorial experiments (completely randomized design of three replications) were conducted in the greenhouse. Treatments in the first experiment were four levels of foliar application (zero, 2.5, 5 and 7.5 L/1000L) and three moisture levels (field capacity, 75 and 50% of field capacity(FC)) and in the second experiment four levels of soil application (zero, 5, 10 and 20 L/ha) and the mentioned moisture levels. Greenness index, number of claws, number and height of spike, number of seeds per spike, plant height, fresh and dry weights were measured and water-use efficiency was calculated. Both soil and foliar applications methods increased grain yield, plant dry weight, greenness index and water-use efficiency compared to control. Application of 20 L/ha caused a 13% increase in the number of spikes, and the application of 5 to 20 L/ha increased the number of seeds in spike by 22 to 31%, respectively. The number of seeds per spike increased by 7.5 L/1000L foliar application. The highest greenness index (38% increase in 0.75FC treatment) and water-use efficiency (0.55 g/L in 0.5FC condition) was observed with soil application of 20 L/ha fertilizer. Fertilizer application in dry conditions prevented dry-weight loss and soil application was more effective. Application of fertilizer increases the growth/performance of the plant and it can be used to improve the quantity/quality of the yield, especially in arid/semi-arid regions.

Safflower (Carthamus tinctorius L.) is a multipurpose crop that is widely grown in arid and semi-arid regions of the world, mainly to produce high-quality edible oil rich in unsaturated fatty acids. The objective of this study is to investigate the effects of regulated deficit irrigation (RDI) and partial root zone drying (PRD) methods on yield, yield components and water productivity efficiency of safflower. This study was conducted in the Experimental Research Station located in Agricultural and Natural Resources Sciences University of Khuzestan during the 2020 to 2021 and 2021 to 2022 growing seasons. The experiment was designed as a completely randomized block with one control treatment (Conventional irrigation) and 4 deficit irrigation treatments and in four replications. The results showed that the different irrigation methods had a significant and decreasing effect on plant height, number of seeds per plant, thousand seed weight, seed yield, biological yield and oil yield traits. Comparing RDI80 and PRD80 treatments, the highest seed yield (3.4 tons/ha) and oil yield (845.7 kg/ha) and the highest value of water productivity index was obtained from RDI80 treatment. Also, comparing RDI60 and PRD60 treatments, the highest seed yield (2.2 tons/ha) and oil yield (584 kg/ha) was obtained from PRD60 treatment. Therefore, according to the obtained results, it is recommended to use the RDI80 regulated deficit irrigation method to reduce 20% and the PRD60 partial root zone drying method to save 40% of water requirement for safflower cultivation in hot and dry areas with limited water resources.

Wetland habitats are one of the most important natural ecosystems in the world. Evaluating and managing these valuable ecosystems require accurate and up-to-date data that remote sensing makes it possible. In this study, the changes of Anzali International Wetland in Gilan province, Iran, were investigated using Landsat satellite images and the Modified Nomalized Diffrence water index (MNDWI) in Google Earth Engine (GEE) platform during the years 1986 to 2020. To monitor waterbodies changes, two classes of water and non-water area were classifeied by Support Vector Machine (SVM) algorythm and MNDWI index was used to distinct the water surface areas. On the other hand, climate data including TRMM satellite data and PDSI index from TerraClimate data and Caspian Sea water level data were used to determine their effects on water level fluctuation of the wetland. The maps of SVM classification had overall accuracy more than 87% and Kappa coefficient was more than 88%. The wetland water body loss has decreased by 20% in its area according to MNDWI index maps, it has reached from 5926 hectares to 954 hectares, so that initially (until 2000) there was an upward trend and then a downward trend in the wetland water level. Also, the water level of Anzali wetland have been affected more by the sea level than the climatic factors. The results show that water indices and Google Earth Engine are efficient tools to identify the trends of water level changes of wetlands, and could provide more detailed scientific guidance to protect and manage natural resources in the studied areas.

This research was carried out with the aim of achieving the most suitable planting distance and the amount of nitrogen fertilizer per unit area on four promising rice lines 10, 11, 15, and 16 at Kohgiluyeh and Boyerahmad province, Choram city station in 2016 and 2017. The factor of planting distance in three levels of 15x15, 20x20, and 25x25 cm, and the amount of nitrogen in three levels of 50, 100, and 150 kg of N per hectare were factorially considered in the form of a randomized complete block design with three replications. Traits were containing plant height, days to flowering, days to maturity, harvest index, grain yield, and yield components. The result of the analysis showed there is a significant differences between genotypes at a 1% probability level. ANOVA revealed significant differences for different transplant spacing and different rates of nitrogen fertilizer on comparison of grain yield and thousands grain yield. Effects of transplant spacing, and rate of N level so interaction between N level and on grain yield showed significance at 5% probability level. The effect of genotype and transplant spacing were non-significant on days to flowering, days to maturity, while the effect rate of N level significant on other traits at the 5% probability level. The number of seeds per square meter and the number of fertile tillers were the effective components on the difference in grain yield. In whole genotypes had significant difference at most case second transplant spacing with other transplant spacinges. The maximum grain yield was related to genotype No 3 in G3 ×D2× N2 with average of 9.503 Ton ha-1. Therefore, this treatment can be used taking into account economic and environmental considerations.

This research was conducted to study the effect of salicylic acid (SA) and methanol (M) spraying on yield and components yield of rapeseed, Hayola 401 cultivar, under deficit-irrigation stress conditions in Khuzestan province, Shams Abad, Dezful region in 2016 and 2017 crop years. In this research, the irrigation cycle was conducted in three levels (70, 140, and 210 mm evaporation) as the main plot, SA in three levels (0, 100, and 200 µmol), and M in 3 levels (0, 10, and 20 v %) as the secondary plots with three replications. According to the simple effect of deficit-irrigation treatment, SA and M spraying treatments showed a significant difference in 1% p-value at the most evaluated traits except the plant height and the number of pods. The two-way effect of deficit-irrigation stress and SA and M was significant only in the traits of pod length at a 1% significant level. The results showed that the maximum yield of grain was obtained under deficit-irrigation stress with 70 mm evaporation, 100 µmol SA solution spraying and 20 v% M spraying (3272 kg/ha). In addition, the minimum yield of grain was obtained under the deficit-irrigation stress condition with 210 mm evaporation, zero-spraying SA, and 10 v% M spraying (315 kg/ha). The maximum oil percentage was observed in stress with 70 mm evaporation, 200 µmol SA spraying, and 20 v% of M (50.3%). In addition, the minimum oil percentage was observed in 210 mm evaporation and zero-spraying SA and M (31.7%). Based on the results, the best deficit-irrigation treatment was 70 mm evaporation, and yield decreased by increasing the deficit-irrigation stress. Moreover, the gain yield and oil percentage increased by M and SA solutions spraying.

Potato (Solanum tuberosum L) is one of the tuberous products that plays an important role in the nutrition of the world's people, therefore, in order to investigate the effect of growth-promoting bacteria on the agronomic and qualitative traits of different potato cultivars, an experiment was carried out.  The conducted research in 2018 examined the effect of growth-promoting bacteria on the quantitative and qualitative agricultural traits of various cultivars of Solanum tuberosum under drought stress in greenhouse and garden conditions.  In the garden part, the hybrid of Enterobacter cloacae bacterium × 100% water requirements × Jelly cultivar with means of 48.53 ton/ha and 7.87 kg/m3 had the maximum tuber yield and water productivity, and the hybrid of no bacteria × 60% water requirements × Milva cultivar with means of 23.40 ton/ha and 3.8 kg/ha had the minimum tuber yield and water productivity among the treatments. Actually, using Enterobacter cloacae bacterium in addition to 100% water requirement increased tuber yield and water productivity up to 51.78 and 51.72%, respectively, compared to the no growth-promotion bacterium × 60% water requirements.  The indexes of tolerance (TOL) and sensitivity to water scarcity stress in the garden showed that Jelly cultivar in mild stress condition, Agria cultivar in severe stress condition in control treatment had minimum TOL than the other conditions according to TOL index. In addition, Jelly cultivar, when Enterobacter cloacae is used as a growth-promoting bacterium, was superior to the control treatment and use of Azospirillum bacteria according to YP, MP, and GMP indexes. It showed tolerance against the made stress and had a higher tolerance than the two other treatments in mild stress conditions.  In general, in laboratory, greenhouse and field conditions, water deficit stress caused the reduction of the evaluated traits. The use of Interbacterculase bacteria was effective in improving the proposed traits compared to its non-use bacteria and caused increasing in most of the proposed traits.

Today, water erosion is considered one of the most important forms of nature destruction, and the problems caused by it are inseparable problems of the country's watersheds. Among the numerous environmental factors affecting soil erodibility, lithology, topography and climate factors are the most important factors affecting soil erodibility. The purpose of this research is to investigate soil properties including number of drops impact (NDI), mean weight diameter of soil aggregates (MWD), soil penetration resistance (PR), soil cohesion (COH), saturated conductivity (Ks) and soil erodibility index (K). Therefore, six rock types (granite, limestone, ophiolite, shale, marl and sandstone) were selected in Razavi Khorasan province and sampling was done in three slope classes 0-10, 10-25 and more than 25% in 2021. In order to compare soil erodibility in similar rocks in different climates, limestone was selected in Tabas city (dry climate). The results showed that the average soil erodibility index and other indices have a significant difference (P<0.001). The results of measuring soil erodibility index in different slopes showed no significant erodibility index in three slope classes (sig=0.893, p<0.05). The comparison of the average soil erodibility in different climates in rocks similar to Paleogene limestone with a value of 0.83 in Tabas limestone and 0.96 (ton ha h / ha MJ mm) sarakhs limestone showed that the average soil erodibility in different climate has a significant difference (sig=0.023, p<0.05). The results of measuring CSEI index showed that the highest amount of reduction in erodibility reflected by this index is in granite with a value of 64% and the lowest value in shale with a value of 25%.