نشریه مهندسی زراعی
سال چهل و پنجم شماره 1 (بهار 1401)

Salinity is one of the growth-limiting factors for pistachio (Pistacia vera L.) crop production in semiarid and arid soils of Iran. Salinity poses two major threats to plant growth: osmotic stress and ionic stress. In addition, it also manifested an oxidative stress. The deleterious effects of salinity affect different physiological and metabolic processes of plants. The uptake of high amounts of salt by the plant leads to the increase of the osmotic pressure in the cytosol. Under this condition compatible osmoprotectant, such as proline and soluble sugars, is produced to protect the cells against the adverse effects from salt stress. High accumulation of proline is associated with tolerance to stress. Na+ and K+ homeostasis plays a vital role in the growth and development of higher plants under salt conditions owing to potassium–sodium (K+–Na+) interaction and is often associated with K+ deficiency. Application of potassium fertilizer affect plants growth and tolerance under salinity stress. The potassium is indispensable for several physiological processes, including the maintenance of membrane potential and turgor, enzyme activation, stomatal movement, regulation of osmotic pressure. Therefore the objective of this study was to evaluate the effect of potassium sulfate fertilizer application on growth, photosynthetic pigments, proline, soluble sugar and Na and K Uptake by Badami-riz Zarand P. vera L. (the main pistachio rootstock in Iran’s pistachio plantation area) seedlings under salinity stress.

This study carried out in greenhouse condition as a factorial experiment based on a completely randomized design and in three replications. Experimental factors was salinity of irrigation water (in three levels including 0.65, 5 and 10 dS m-1) and potassium sulfate fertilizer application )in three levels including without application or control, 150 and 250 mg kg-1 soil). Pistachio (Pistacia vera L. cv. Badami-riz Zarand) seeds were surface sterilized with solution of sodium hypochlorite in distilled water. Seedlings were transplanted in plastic potscontaining 10 kg of soil. The pots were maintained in the greenhouse under 25 ± 4 ◦C temperature and under natural light. The mean relative humidity was 40 %. At the end of growth period (six mounth), the plants were harvested and leaf area, root dry weight, shoot dry weight, chlorophyll a and b, total chlorophyll, carotenoids, proline, spluble sugar, root and shoot K and Na concentration were measured. In addition, the K and Na uptake in shoot and root, as well as K/Na ratio were calculated. Analysis of variance (ANOVA) was performed using SAS program version 9.4 (SAS Institute, Cary, NC). Significant differences of the mean values (P <0 .05 for F-test) were determined by Duncans’s Multiple Range Test.

Results indicated that with increasing salinity stress, leaf area, root, and shoot dry weight, chlorophyll content and shoot and root K uptake decreased, while carotenoids and shoot and root Na concentration increased. The highest and lowest value of leaf area, root, and shoot dry weight, chlorophyll content and shoot and root K uptake were observed in control and high salinity levels (10 dS m-1) treatments respectively. Application of potassium sulfate fertilizer at both levels (150 and 250 mg kg-1) led to a significant increase in leaf area (8.1 and 8.7 % respectively), root dry weight (21.2 and 20.0 %), shoot dry weight (21.3 and 19.9 %), total chlorophyll (10 and 7.8 %), carotenoids (32.2 % and 35.7), proline (21.1 and 14.4 %), root K concentration (44.1 and 56.2 %), shoot K concentration (11.0 and 26.9 %) and K uptake in root and shoot. in high salinity treatment seedlings showed higher Na+/K+ ratio in the roots than that of the shoots. In addition, application of potassium sulfate fertilizer decreased Na uptake in shoot and root. Moreover, the addition of potassium fertilizer increased K/Na ratio in the shoot and root. The results also indicated there were no significant difference between potassium sulfate fertilizer levels (150 and 250 mg kg-1) effects on investigated traits.

It could be concluded that application of potassium sulfate fertilizer results in reduce the negative effects of salinity stress and subsequently enhance tolerance to salinity stress and improved P. vera L. seedlings growth. Therefore, nutrient management of potassium can be considered for decline of negative effects of salinity in P. vera L. v. Badami-riz Zarand seedlings.

Streptomyces is the most important and dominant genus of actinomycetales with more than 664 species which some of its species may stimulate plant growth through nutritional and physiological mechanisms that include: dissolution of phosphates, production of siderophores and phytohormones, biological Nitrogen fixation and production of antifungal metabolites. Silicon has significant positive effects on improving the growth and physiological characteristics of the plant by improving the root system, biosynthesis of phytohormones, resistance to biological and non-biological stresses and nutrient uptake. Improvement of the silicon concentration in the plant depends on its availability in soil. Soil application of resources with appropriate amount of silicon is of great importance in increasing the availability and uptake of silicon. It is also documented that the co-application of plant growth promoting bacteria and silicon is a useful and efficient method to increase plant growth and yield under normal and stress conditions. Due to beneficial effects of plant growth promoting bacteria and silicon in improving crop growth and also the importance of soil application of different silicon sources, the aim of this study was to Investigate the effect of Streptomyces isolate, silicon application using calcium-magnesium silicate source and the combined application of Streptomyces + silicon on growth parameters, chlorophyll content and accumulation of some nutrients in soybean (Glycine max L.).

A pot experiment was designed as factorial in a complete randomized design with 3 replications under natural light and temperature conditions. Experimental treatments included soil application of calcium-magnesium silicate source (37.9% silicon dioxide) at four levels 0 (M1), 200 (M2), 400 (M3) and 600 (M4) kg Si ha-1 and two levels of inoculation with Streptomyces isolates (no inoculation (B0) and inoculation with Streptomyces (B1). Surface-sterilized seeds were inoculated with a suspension of (107 CFU mL-1) Streptomyces isolate. The effect of experimental treatments on plant development stage (late vegetative growth period) was investigated. The soybean plants were harvested after 10 weeks of growth period from soil surface. Plant growth parameters including shoot and root biomass, root volume and plant height were determined. Also, chlorophyll content (a, b, Total) and concentration of nitrogen, silicon, phosphorus and potassium in the shoot were measured.

The results of the present study showed a positive and significant effect of the co- application of silicon and Streptomyces inoculation on improvement of the growth characteristics and chlorophyll content compared to their separate application. The highest amounts of shoot biomass (19.3 g per pot), root biomass (7.6 g per pot), root volume (38.07 cm3), plant height (98 cm) and chlorophyll a (18.07 mg / g), chlorophyll b (14.4 mg / g) and total chlorophyll (32.4 mg / g) were measured in the co-application of 600 kgha-1 Si (M4) and Streptomyces inoculation (M4B). .Our results showed the improvement of soybean growth parameters could be due to the positive effect of Streptomyces isolate on plant growth promotion and utilization of calcium-magnesium silicate in soil. Combined application of silicon and Streptomyces inoculation increased the concentration of silicon, nitrogen, phosphorus and potassium in the M4B treatment compared with the lonely application of highest level of silicon source (M4) by 16.25, 7.45, 45.6, 51.7%, respectively.

Based on the results of the present study soil application of calcium-magnesium silicate increased plant growth and physiological factors. Streptomyces inoculation improved the effects of calcium-magnesium silicate levels to enhance growth parameters, chlorophyll content and nutrient concentration (silicon, nitrogen, phosphorus and potassium) in soybeans. This study was carried out in pot experiment at the vegetative growth stage of soybean. Therefore, supplementary studies are necessary in field and harvest stage.Keywords: Streptomyces, inoculation, silicon, soybean, plant growth

In the modern era, population growth has led to an increase in many related issues. One of these is the causes related to agriculture. In recent years, the use of planting techniques that can properly prepare the seedbed and sow the seeds at an almost uniform depth, has become more necessary than ever. SolidWorks software was used to design this car. Statistical data were analyzed using IBM SPSS software. Cultivation on raised bed is one of the most modern cultivation methods in the world. In this type of cultivation, without any tillage operations and directly, all cultivation stages are done in one stage. The device was built in six rows. In order to investigate six types of planters for growing chickpeas (representative of coarse-grained) and rapeseed (representative of fine-grained), an experiment was conducted using strip plots in a completely randomized block design with four replications in the 2021-2022 crop year. Soil moisture content, soil texture and soil temperature were extracted before planting. The parameters measured in this plan were: fracture percentage, planting depth, uniform distribution and seed fall and seed germination percentage. The machine was built with a working width of 1.5 meters, a length of 1.5 meters and a height of 2.3 meters. The construction of this car was done in the industrial complex of Barzegar Machine in Hamedan city. Type of planter in six levels b1: V-shaped, b2: U-shaped, b3: T- inverse, b4: Two-plate V-shaped, b5: cross-shaped and b6: Tulip-shaped were tested. The main purpose of this study is to build a device with a suitable planting arrangement for direct sowing machines in Iran (modeled on growers from other countries), to develop technical knowledge of the application of some planting methods, to eliminate the traditional methods of the past, Instantaneous monitoring of planting machine performance as well as increasing farmers' confidence in using planting machines to grow fine-grained crops. SolidWorks2021 software was used to design this machine. Statistical data were analyzed using IBM SPSS 25 software. The device was built in six rows. In order to evaluate six types of planters for growing chickpeas and rapeseed, an experiment was conducted using strip plots in a completely randomized block design with four replications in the crop year 1399-1400. The parameters measured in this plan were: fracture percentage, planting depth, uniform distribution and seed fall and seed germination percentage. The construction of this car was done in the industrial. Complex of Barzegar Machine in Hamadan. The type of planter was tested in six levels: b1: v-shaped, b2: u-shaped, b3: inverted t, b4: two-plate v-shaped, b5: cross-shaped and b6: tulip-shaped. The general purpose of this study is to build a device with suitable planting arrangement for direct sowing machines in Iran. The results showed that the crusader has a significant advantage over the other operators in the studied four parameters at the level of 5%.The general review of the research results showed that the crusader has a significant advantage over the other operators in the studied four parameters at the level of 5%. Compared to the other five types of crushers and in relation to the highest numbers obtained from the treatments, cross-planting increased the uniformity coefficient of planting depth by 7%, uniformity of seed longitudinal distances by 23% and germination percentage by 2.3% compared to other Has been planted. The percentage of seed breakage decreased by changing the distribution from cast iron to plastic oblique by 1.25%. These results show the superior design and distribution mechanism, planters and different settings of the machine in the cultivation of coarse and fine grain crops. Increasing the growth rate did not have a significant effect on the parameters of fracture percentage, uniformity coefficient of planting depth and coefficient of uniformity of seed longitudinal distances. However, it has significantly reduced the green percentage. The overall results showed that a cross-planter with a diagonal plastic distribution and a telescopic fall tube is more suitable for sowing coarse seeds. The mentioned planters are not suitable for small seeds. In general, with the results and relationships obtained from the research, it was possible to monitor planting operations and receive feedback on the improper operation of the machine in agricultural fields. The results and coefficients of explanation of the field test were weaker than the laboratory results. Compared to the other five types of crushers and in relation to the highest numbers obtained from the treatments, cross-sowing increases the uniformity coefficient of planting depth by 7%, uniformity of seed longitudinal distances by 23% and germination percentage by 2.3% compared to other planters.

Soil is one of the important parts of ecosystem. Land use change and developed agriculture can lead to soil loss and land degradation because they have damaging effects on soil properties including soil organic carbon, aggregate stability and soil erodibility factor. Soil erodibility factor can be measured by different methods including experimental plots. It shows that the problem should be dealt directly and it demands high amount of cost and time. The factor can be calculated by soil properties such as soil organic matter and particle size distribution. They play a crucial role for sustainable ecosystem and decreased soil erosion. Since a few decades ago, deforestation has caused increased soil degradation and it has had devastative effects on soil surface and subsurface properties. This study investigated soil erodibility factor by different methods in three land uses including forest, grassland, and cropland at two depths in Sidasht of Guilan province. Soil quality index was calculated for evaluation of effects of land use on soil quality degradation.

The study area is located in Tootkabon in Guilan province (latitude 36º 50' 10" N, longitude 49º 39' 15" E). Parent material is limestone and geomorphologic units that are comprised of hill land and plateau. The soil moisture and temperature regimes are xeric and thermic, respectively. In order to reach the goals of the study, samples were collected from three land uses of forest, grassland, and cropland at two depths of 0 to 10 and 10 to 20 cm in regards to parent material, slope class, and equal slope aspect. Soil samples were prepared in two categories: the disturbed soil and the undisturbed ones. After becoming air drying, the disturbed samples were sieved by a 2 mm sieve. Soil properties such as soil texture, bulk density, soil organic carbon, CaCO3, and soil stability were measured. Soil erodibility factor is calculated by nomograph, Vaezi and Ostovari methods. Also sensitivity index and stratification ratio were taken into account. Soil quality index was determined using linear and nonlinear scoring methods based on minimum data set. All soil parameters were tested using one-way analysis of variance and the differences among means were analyzed using Duncan's significant difference test at the probability level of 0.05.

Results showed that the effects of land use and soil depth on bulk density, soil texture and soil erodibility factor using nomograph method were non-significant (p ≤ 0.05). The amount of organic matter, soil structure stability index and soil erodibility factor of Vaezi method were significantly decreased by increasing the depth. MWD and GMD at forest were higher than cropland, and CaCO3 and soil erodibility factor of Ostovari method at forest were lower than cropland. In comparison with other methods, soil erodibility factor of Ostovari method demonstrated that the effect of land use was significant (p ≤ 0.05). Soil properties including bulk density, MWD, organic matter, and soil erodibility factor of Ostovari method were selected as the minimum data set. Results of nonlinear scoring method were better than linear scoring method because the linear scoring method just showed the effects of soil depth on soil quality index (p ≤ 0.05). The soil quality index using linear scoring method was decreased by increasing the depth. However, soil quality index using nonlinear scoring method in forest was higher than cropland, and it was decreased by increasing the soil depth. It was found that non linear scoring methods are superior to linear and soil quality index using the nonlinear scoring method showed better the soil quality among different land uses.

Sensitivity index and stratification ratio values showed that land use change and soil depth effect on soil properties including CaCO3, organic matter, structure stability index and MWD. The stratification ratio values more than 1.5 for organic matter and soil structure stability index can be stated that these properties can show the degradation of soil quality due to land use change. Soil quality evaluation showed that in relation to the effect of land use on soil quality index, nonlinear scoring method is superior to linear scoring, so that forest and agricultural land use had the highest and lowest soil quality index by nonlinear scoring method, respectively. Therefore, due to the high sensitivity of soil quality to land use change, preventing land use change is one of the necessary measures for sustainable soil management in the study area.

Climate is one of the most effective factors on soil formation, evolution and degradation. It is include different parameters which mainly based on precipitation and temperature. In the recent years the effects of global warming and climate change has extremely enhanced. Climate change as an important phenomenon is effective on precipitation parameters including volume, intensity and concentration which categorized in the temporal and spatial variations. Quantifying the effects of climate change is important for identifying critical regions prone to soil erosion under a changing environment. Land-based ecosystems are influenced by patterns of air temperature and precipitation, which include daily and seasonal changes along with humidity and wind, and the nature of the land surface. Global climate change already has observable effects on the environment. Regarding the importance and effectiveness of climate factor and climate changes during the time, it is essential to focus on climate changes on water behavior at different scales. Indeed, precipitation parameters interacting the soil parameters are influencing on runoff potential in the fields and watersheds. In this regard Rainfall-runoff erosivity (R) is one key climate factor that controls water erosion. Universal soil loss equation (USLE) is the main common equation to predict soil loss, this equation consisting 5 factors which R-Factor (Rainfall erosivity factor) is one of the effective factors in this equation.

Regarding the effect of climate on soil erosion processes therefore, monitoring of climate is really important. In this study in order to evaluate the climate changes based on time series, four climatological stations including, Ardal, Saman, Izeh, and Dehdez were selected. Using the statistical data of precipitation, calculation of eroding index was performed until 2017. The ACF (Auto Correlation Function) and PACF (Partial Auto Correlation Function) for precipitation data were prepared, afterwards the ADF test was performed at confidence level of 1, 5 and 10 percentage. Then the suitable parameters for p, r and q were selected and the SARIMA (Seasonal auto-regressive integrated moving average) model was provided. The statistical analyses were performed with Stata SE, Minitab 18 and SPSS 19. Moreover, the graphical trends of rainfall as an index of precipitation and the rainfall erosivity factor (R-Factor) were presented. Also, the spatial distribution of R-Factor (in the form of GIS-Maps) were provided including three separated maps based on real data, 5 year predicted and 10 year predicted data. So there was a possibility to monitor and compare the spatial distribution of R-Factor at different time periods. Then based on the area, the percentage of rainfall erosivity index was calculated for the study area based on the real data, 5 year predicted and 10 year predicted data. In addition, the statistical parameters including R-square, RMSE, P-value and so on were calculated for the best model (SAR12) regarding all climatological stations.

Our results depicted that to present the trend of precipitation variations as erosive factor the ARIMA (0,0,1)×(1,1,1)12 was the best model. Also, the seasonal autoregressive moving average showed the variation of precipitation in the study area which located in the southwest of Iran. The results of modeling stated that reduction of precipitation for 5 and 10 year periods after 2017. According to amount of monthly simulated of precipitation, the amount of erodibility index was obtained in the area which illustrated the declining trend until 10 year. According to ADF test for all evaluated climatological stations the probability for Ardal was 0.34, for Dehdez was 0.425, for Saman was 0.345 and for Izeh was 0.177, therefore there was difference between climatological stations. Furthermore, the statistical analyses for SAR12 model revealed that the R-square for Ardal station was 0.492, for Dehdez was 0.716, for Saman was 0651 and for Izeh was 0.576. Moreover, approximately 37 % of area has very low rate of erodibility index without previous occurrence.

Our results clearly confirmed the importance of climate factors and climate change during the time. As results illustrated regarding the variations of precipitation the R-Factor changed. Moreover, climate change is effective on spatial variations of crop cover in the watersheds. Climate change is capable to alter the crop cover patterns in the watersheds and the changes in crop cover distribution and runoff could change the soil erosion potential. Generally, based on results has to focus on water resources conservation in the study area to preserve soil and water against erosive forces and try to improve the vegetation cover because of decreasing of precipitation. In order to manage the soil resources, we need to monitor the climate changes in the watersheds and try to enhance the vegetation covers in the critical parts on the fields.

Introduction:

 The highest amount of water consumption is allocated to the agricultural sector, which has led to a water crisis due to increasing demand for food production and non-conservative agriculture and climate change in some countries. Sugarcane needs a lot of water during the growing season and is sensitive to drought. In drought conditions and water stress, the intensity of reverse flow of water to the soil surface increases and can cause salinization of the soil around the roots of sugarcane, which is a relatively sensitive plant related to salinity. Due to the high-water consumption in sugarcane fields and also the shortage and decline of water quality in dry years, this study aimed to investigate the effect of conventional and deficit irrigation by variable and fixed alternate furrow irrigation on soil salinity and some nutrient concentration consist of phosphorous and potassium in sugarcane field.

Materials and Methods:

 To investigate the effect of irrigation methods on salinity distribution and concentration of phosphorous and potassium in soil, this experiment was conducted with independent variables of irrigation method treatment including conventional (complete) irrigation, variable alternate furrow irrigation and fixed alternate furrow irrigation, irrigation round treatment including before irrigation, after one and two times irrigation, sampling location treatment including bottom, middle and top of raised bed and sampling position treatment consist of start, middle and end of furrow. The experiment was performed factorially in a completely randomized design with three replications in sugarcane fields of MianAb in Susa. Statistical analysis was performed using SPSS software and mean comparisons were performed by Duncan's multiple range test. Charts were drawn using Excel software.

Results and Discussion:

 The results showed that irrigation method is mainly affects salinity distribution and concentration of phosphorus in soil. The fixed alternate furrow irrigation method had the greatest effect on soil salinity changes and reduced the salinity as compared to the conventional method and the variable alternate furrow irrigation. In general, in the conventional irrigation method (complete irrigation of all furrows) and variable alternate furrow irrigation, there is no constantly dry furrow as compared to the fixed alternate furrow irrigation method, and this intensifies the accumulation of salts on the sides and the top of raise beds. Increasing the frequency of irrigation (irrigation round) reduces the soil salinity so that in soil samples before irrigation, soil salinity was 2.30 dS/m and with one round irrigation, this amount decreased by 7.8% to 2.12 dS/m and with two rounds of irrigation reached to 2.09 dS/m. In terms of locative variation of salinity related to the fixed alternate furrow irrigation method, the lowest amount of salinity was observed in the bottom of the raised bed. With increasing distance from the beginning of furrow, an upward trend in soil salinity was reported. Regarding the change in the amount of available phosphorus in the soil under the influence of irrigation method, any of the deficit irrigation methods can be used as an alternative to conventional irrigation. The highest amount of soil phosphorus was reported in the middle of the raise bed. Soil potassium changes were not directly affected by irrigation method and the highest amount was assessed in the bottom of the raise bed. In terms of salinity, the lowest value was at the bottom of the furrows and the highest value was at the top of the raise bed. Unlike salinity changes, soil phosphorus had the highest accumulation in the middle of the raise bed and reached a minimum at the top of the raise bed. A relatively uniform trend was observed in changes in soil phosphorus from the beginning to the end of the furrow. Contrary to salinity changes, the highest amount of available potassium in soil was observed in the bottom of raise bed and a decreasing trend in soil potassium was reported from the beginning to the end of furrow. In general, based on the results, the average level of soil salinity and potassium and the highest amount of phosphorus were reported in the middle of the raise bed.

For optimal water use and soil salinity management, application of deficit irrigation methods especially fixed alternate furrow irrigation instead of conventional irrigation method, is recommended. In case of salinity and concentration of mentioned nutrients, the top of the raise bed in all three irrigation methods, would not be a suitable place for plant cultivation.