Showing 30 results for Loss
S Jamali, E Pourjam, N Safaee, A Alizadeh,
Volume 13, Issue 47 (4-2009)
Abstract
In order to estimate the loss of rice caused by white tip nematode, (Aphelenchoides besseyi), to Alikazemi cv., two series of experiments were conducted in greenhouse and microplot conditions at Rice Research Institute, Rasht (Guilan province) during 2005-2006. The microplots sizes were 0.5×2 meter. Rice seedlings were inoculated by plastic tube method with 0, 100, 300, 500, 700 and 900 nematodes per plant. The experiments were arranged in greenhouse and microplot conditions as a completely randomized design and completely randomized block design with four replications, respectively. The factors under investigation consisted of symptoms (number of plants and Leaves infected), yield and population density of nematodes. The variance analysis of data showed significant differences among treatments in all parameters. The minimum infestation level leading to symptoms and yield loss in microplot condition (500 nematodes) was greater than greenhouse (300 nematodes). Regression analysis of data revealed that the yield reduction was mainly explained by population of nematodes in greenhouse and microplot (R2= 92.56, R2 = 91.55). Also, there was a positive correlation at 5% level of probability between disease incidence and nematode population (R2= 84.42, R2 = 75.27). The resulting equations from regression can be used to estimate crop loss from population of nematodes.
O Hashemi Beni, M.h Salehi, H Beigi Harchegani,
Volume 13, Issue 50 (1-2010)
Abstract
Although soil organic matter (SOM) constitutes a small portion of soil bulk weight, it has a tremendous effect on physico-chemical and biological properties of soils. It is also one of the most important indicators of soil quality and its production. Soil organic matter determination is required for soil fertility management and soil pollution purposes. Wet oxidation procedure of Walkley-Black is a routine, relatively accurate and popular method for the determination of soil organic matter, but it involves the use of chromate and high cost of analysis. Therefore, loss-on-ignition (LOI) procedure as a simple and cheap method of SOM estimation which also avoids chromic acid waste has got more attention. The aims of this study were (i) to establish the relationships between LOI method and SOM as determined by Walkley-Black method for four major plains of Chaharmahal-va-Bakhtiari province and (ii) to determine the optimal temperature of the LOI. To do this, 205 soil surface samples were randomly collected from 0-25 cm depth of Shahrekord, Farsan, Kohrang and Lordegan plains to determine soil organic matter by Walkley-Black method and LOI procedure at 300, 360, 400, 500 and 550 oC for two hours. To determine the optimum temperature for ignition, 40 soil samples were selected to compare the SOM and CCE before and after ignition for each temperature. Results showed a positive, linear significant relationship existed between LOI and wet oxidation in each plain. Coefficient of determination (R2) of the equations was higher for individual plain than the overall equation. Coefficient of determination and line slope decreased and error (RMSE) increased with increasing ignition temperature. At higher contents of calcium carbonate, the rate of line slope decrease with increasing ignition temperature was more noticeable. This may be due to the destruction of carbonates at higher temperature. A temperature of around 360 oC was identified as optimum as it burned most organic carbon, destroyed less inorganic carbon, caused less clay structural water loss and used less electrical energy.
S. H. Sadeghi, M. Gheysari, M. Kavyani,
Volume 16, Issue 59 (4-2012)
Abstract
To maintain a high system-uniformity and also acceptable water use efficiency in a solid-set sprinkler irrigation system, the total committed pressure variation to subunits should not exceed 20% of the pressure head of the sprinkler which operates with the average pressure. Although some references often recommend giving the major part of this pressure variation to laterals, a scientific and precise criterion that allows designers to minimize the costs has not yet been developed. In this study, regarding the usual design criteria of this system in Iran and also respecting hydraulic rules, an economical analysis was conducted in order to optimize the system based on the appropriated permitted pressure head loss to each subunit. Then, the system irrigates the possible largest area by using minimum weight of pipe. The methodology consisted of 13 slope treatments for each subunit (0, ±0.1, ±0.5, ±1, ±2.5, ±5 and ±10%) and also the ratio of appropriated allowable head loss to the manifold (2.5, 5, 7.5, 10, 12.5, 15 and 17.5%). A simple software was developed to determine the size and the length of the manifold and laterals for each combination as well as their total weight and total irrigated area. Several criteria such as maximum and minimum velocity of water in the pipe, maximum head loss which occurs in 100 m of the manifold, maximum permitted head loss for each subunit and also maximum length of the laterals were considered here in order to derive practical design combinations. Because a constant inlet pressure for each subunit leads to a constant cost of energy, then the ratio of total weight of pipelines to the total irrigated area (Wtot /A0) was chosen as the standard, which helps to distinguish the best appropriation of allowable head loss to the manifold or laterals. Graphical diagrams were presented to help designers to know how to distribute the total permitted head loss between manifold and laterals. In general, results showed that total pressure head variation of each subunit greatly affects the system costs and also the total optimized appropriated pressure head loss to each subunit is greatly dependent on its own slope.
S. H. Sadeghi, S. F. Mousavi, M. Heidarpour,
Volume 16, Issue 60 (7-2012)
Abstract
Precise calculation of inlet pressure into sprinkler laterals is an important problem for proper distribution of uniformity. The adjusted average friction correction factor, FaAVG , provides the possibility of calculating the inlet pressure to mutli-outlet pressurized irrigation pipelines when the first outlet spacing from the pipe entrance is arbitrary. To investigate the effect of allowable head-loss in the lateral pipeline on inlet pressure, a new equation was developed for calculating this factor. A progression coefficient was assumed for variable discharge of the outlets. The results showed that though the inlet pressure of the lateral depends on the head loss between the outlets, it is negligible when more than 15 outlets are used. It was also concluded that when N is less than 15 and the ratio of distance between inlet and first outlet to outlet spacing is less than 1, the conventional approaches overestimate the inlet pressure. In this research, a new equation was also developed for Christiansen friction factor in which the first outlet is located at a fraction of outlet spacing. This new factor is dependent on the head loss between the first and last outlets, in addition to the number of outlets and the power of velocity equation. The results of applying this new factor showed good correlation with other researchers’ numerical results when a large number of outlets are coalesced.
N. Pourabdollah, T. Honar, R. Fatahi,
Volume 18, Issue 67 (6-2014)
Abstract
Most of researches related to hydraulic jump have been done on horizontal and rough beds, and little attempt has been made on rough beds with adverse slopes. The aim of this study was to investigate the influence of rough beds with adverse slope on hydraulic jump characteristics. The variations of energy loss in stilling basins with three adverse slopes and three different roughnesses were studied. Results showed that increase of roughness caused that relative depth of jump in stilling basins with rough bed and adverse slope decreased as compared to horizontal smooth beds. The experiments were performed on rough beds in different conditions where Froude number ranging between 4.9 and 7.8. Result showed that reduction of relative depth was about 31.15%. Results also showed that in such cases the relative energy losses are more than that for classic conditions.
A. Ahmadi, T. Honar,
Volume 18, Issue 70 (3-2015)
Abstract
One of the most important problems in the design of a stilling basin is determination of the exact location of the hydraulic jump or stabilization of the hydraulic jump. In the present study, the effects of different forms of end sills on hydraulic jump characteristics were studied. The experiments were carried out for three different forms of end sills, rectangular, square and stepped, with three heights in two distances and for Froude numbers in the range of 4.7-8.23. The results showed that the end sill with larger cross section (square and stepped) will have a greater effect on reducing sequent depths of hydraulic jump and increasing energy loss than narrow end sills. However, in this type of end sills, water fall and the risk of erosion at downstream is greater.
Engineer H. Talebikhiavi, Engineer M. Zabihi, Dr. R. Mostafazadeh,
Volume 21, Issue 2 (8-2017)
Abstract
Effective soil conservation requires a framework modelling that can evaluate erosion for different land-use scenarios. The USLE model was used to predict the reaction of appropriate land-cover/land-use scenarios in reducing sediment yield at the upland watershed of Yamchi Dam (474 km2), West Ardabil Province, Iran. Beside existing scenario, seven other land-use management scenarios were determined considering pattern of land-use through study area within a GIS-framework. Then, data inputs were prepared using terrain data, land-use map and direct observations. According to the model results, the generated erosion amount was 3.92 t/ha/yr for the current land-use (baseline scenario). For this purpose, conservation practices in dry farming slopes and implementing the scenario 5 (contour farming and remaining crop residuals) can reduce the sediment to 2.02 t/ha/yr. The lowest and highest decreases in sediment yield are projected to be through implementation of scenario 6 (irrigated farming protection with plant residuals) and 7 (biological soil conservation in dry and irrigated farming). The results indicated that, implementing scenario frameworks and evaluating appropriate land-use management scenarios can lead to the reduction of sediment entering the reservoir, and prioritizing soil conservations in the studied area.
A. R. Vaezi, Y. Mazloom Aliabadi,
Volume 22, Issue 1 (6-2018)
Abstract
Water loss and nutrients loss are one of the important signs of natural resource degradation in the catchments. The amount of loss of these resources is affected by several factors including the characteristics of rainfall. In this study, the data of stream discharge (Q), total dissolve solids (TDS), and total nutrient loss ratio (NR) along with rainfall characteristics were analyzed for the events from1988 to 2002 in the Tahamchai catchment, which is owned by a regional water company. Moreover, soil properties were determined by soil sampling from different points in the catchment surface. Based on the results, there was a significant correlation between Q of the river and rainfall height (r=0.24, p<0.05), while its correlations with the rainfall intensity and duration were not statistically significant. On the one hand, this result was due to the inverse relationship between rainfall intensity and rainfall duration; on the other hand, due to the temporal variations in vthe egetation cover in the area, it controlled Q in the intensive rainfalls. The highest Q was in spring (1.68 m3 sec-1) and March (2.58 m3 sec-1). In this period, rainfall height was high and the rainfalls interval was short. Moreover, vegetation cover was weak, so it could not control surface runoff and reduce Q in the catchment. TDS and NR also significantly varied during the months and their highest values were observed in December (282.55 mg l-1) and (61.77 mg l-1), respectively. Mg2+ had the highest amount of water loss in the catchment area. A negative correlation was found between Q and TDS (r=0.41, p<0.001) and NR (r=0.31, p<0.001). This study revealed that spring and autumn were the sensitive period for water loss and nutrient loss in the catchment, respectively. Therefore, promoting the vegetation cover in early spring and reducing improper agricultural practices (tillage and fertilization) could be substantial strategies contributing to conserving the catchment’s resources.
M. Raeisi Asadabadi, M. R. Nour, R. Fattahi,
Volume 22, Issue 2 (9-2018)
Abstract
In order to optimize the irrigation system performance, it is essential to get information about water balance components in the farm. So, the objective of this study was evaluating the performance of the WFD device in determining water penetrated fate in the soil at each irrigation occurrence as one of the important components in evaluating the irrigation water efficiency. By having the water amount infiltrated in the root zone and the deep percolation amount collected and determined by WFD device, contribution of surface losses related to every irrigation occurrence can be determined by the employing water balance equation. This research was carried out in the form of completely randomized design blocks in three replications and under the treatments of 60, 80, 100 and 120% of the irrigation requirement supply of a potato plant in the research farm of Shahr-e Kord University in 2014. To gather the growing season data, before the planting operation, various WFD devices were installed at different depths and locations along furrow. In addition to WFD data, input discharge (using counter), output discharge (measured by flume type 1) and values of soil moisture (theta-probe device) were collected during the harvesting season. The results showed that the mean Nash–Satcliffe coefficient of comparison between the values of calculated and measured surface losses corresponding to it, and also comparison of the values of the calculated and measured residual moisture before each irrigation occurrence were obtained to be 0.87 and 0.98, respectively. Quantity of this indicator in the two conducted comparisons represented the correct and exact performance of the WFD device in the farm operation evaluation. During the farm evaluation process under the experimental furrow, distribution uniformity averages in the experimental treatments were acquired to be 75.56, 83.78, 88.06, and 90.34%, respectively. Likewise, water amount average percolation of root zone (depth losses) in experimental treatments at each irrigation occurrence was measured to be 0.02, 0.07, 0.27 and 0.47m3 for each furrow.
A. Kavian , A. Alipour, K. Soleimani, L. Gholami,
Volume 23, Issue 1 (6-2019)
Abstract
Nowadays, acid rain serves as one of the most serious environmental problems has affected many regions in the world. This phenomenon is characterized by many environmental impacts, such as soil contamination and degradation. Acid rain immediately affects soil, causing soil particles to breakdown and be dispersed; this is the first step to initiate the soil erosion. Therefore, in this study, the effect of different pH levels of acid rain (at different levels) on the soil splash was investigated under laboratory conditions using a rain simulator and a cup splash. In the experiments, acid rains, with the pH values of 3.75, 4.25, 5.25 and normal rains at three intensities of 40, 60 and 80 mmh-1, were studied; finally, a number of 36 samples were taken for statistical analyses. SPSS 23 and EXCEL 2013 software and one way and two-way ANOVA were used for the statistical analysis at a confidence level of 95%. The results showed that at the intensities of 40 and 60 mmh-1, the splash rate was significantly different in all pH treatments, and the acid rain with pH of 3.75 showed the highest splash rate. However, no significant difference was found at the rain intensity of 80 mmh-1, despite the higher splash rate at the pH of 4.25 and 5.25 treatments. Also, the results of the comparison of the means showed that the soil splash rate was also increased with enhancing rain intensity. Finally, the two-way ANOVA test showed that the simultaneous interaction effects of the two factors of pH and rain intensity on soil splash was not significant.
S. Barkhordari, M. Hashemy Shahdany, A. Bagherzadeh Khalkhali,
Volume 23, Issue 3 (12-2019)
Abstract
Seepage losses and poor operational activities are the two main source of water losses throughout the agricultural water conveyance and distribution systems in irrigation districts. This study aims to investigate the performances of two strategies of “canal lining” and employing the “Canal Automation” in order to reduce the losses mentioned above. The investigation was carried out on a couple of main canal reaches of Moghan Irrigation Districts. Two numerical models were simulated by Seep/w software to compare the seepage rate between the canal with and without concrete lining. The results reveal that the ability of concrete lining to reduce seepage losses along the canal is about 10%. Performance assessment of the “Canal Automation” strategy to minimize operational losses within the main canal was carried out employing Model Predictive Control (MPC). The results of the latter strategy indicate that employing the MPC not only reduces the operational losses along the canal by 15% but also improves the operation of the main canal so that the minimum efficiency and adequacy performance indicator was obtained 100% and 83% respectively. Therefore; due to Executive considerations and financial constraints in the same cases, the potential of each of the two strategies can be considered to reduce the conveyance and distribution losses and ultimately choose the most suitable option.
T. Yousefi Babadi, M. Lotfalianand, H. Akbari,
Volume 23, Issue 4 (12-2019)
Abstract
Soil erosion and its consequences are important factors in forest road network management. Cutslopes are the most important source of making sediment among different parts of the forest roads structure. For this research, a new and bare road in district No. 2, series No. 5 of NekaChoob forest, was selected; then the study data was measured. The study design was a completely randomized design in 10 plots with the size of 2 m2 along 500 meters of road with the 8 natural rainfall events. The results of the Pearson correlation showed that among soil properties, the contents of the liquid limit at the 5% confidence level and the plastic limit at the 1% confidence level had positive correlations with runoff and soil loss. Also, organic matter at the 1% confidence level and the contents of the sand at the 5% confidence level had negative correlations with runoff and soil loss. With increasing the soil moisture and bulk density, runoff and soil loss were enhanced. The results of the multivariate model showed that soil loss could be estimated using the Plastic Limit and sand percentage variables with a the correlation coefficient of 0.948.
L. Piri Moghadam, A. Vaezi,
Volume 23, Issue 4 (2-2020)
Abstract
Sloping farmlands are the major sources of soil, water and nutrient losses in arid and semi-arid regions. Information about the impacts of different tillage practices on soil erosion, nutrient loss and crop nutrient uptake on the sloping farmland of semi- arid soil is, however, limited. This study was carried out to investigate the effects of tillage direction on soil, water, nitrogen and phosphorous losses and their uptake by plant in a rainfed wheat land. Field experiments were conducted in two tillage directions: downslope tillage and contour line tillage with four fertilization treatments: control, urea, triple superphosphate, and urea + triple superphosphate at the field plots with 1.75 m ´ 8 m in dimensions by using the randomized completely block design at three replications in Zanjan Township during 2014-2015. According to the results, Significant differences were found between the two tillage practices in soil loss (P < 0.001), water loss (P < 0.001), nitrogen loss soil loss (P < 0.001), and nitrogen uptake by wheat grain (P < 0.001), while phosphorous loss and its uptake did not show any statistically significant difference. Soil and water loss in the downslope tilled plots was 1.65 and 2.50 times higher than the contour line tillage, respectively. Nitrogen loss in the downslope tilled plots was 1.29 times more than that in the contour line tilled plots. Nitrogen loss in the plots was attributed to soil and water loss, so significant relationships were observed between nitrogen loss and soil loss (R2 = 0.59)
and water loss (R2 = 0.55). This study, therefore, revealed that the tillage direction is an important factor controlling runoff, soil loss, and nitrogen loss and its uptake by wheat in the rainfed lands of semi-arid regions. Application of the contour tillage is, therefore, the first step to conserve soil and water and to improve soil productivity in these regions.
A. R. Vaezi, Kh. Sahandi, N. Sadeghian,
Volume 24, Issue 2 (7-2020)
Abstract
In semi-arid regions, soils are weakly aggregated and subjected to water erosion processes especially rill and interrill erosion. There is no information on the rate of these water erosion types in semi-arid soils located in the hillslopes. Therefore, this study was conducted to determine the soils susceptibility to these erosion types in semi-arid region. A laboratory experiment was done in eight soil textures using in a 0.6 m × 1 m flume a simulated rainfall with 50 mm.h-1 in intensity for 60 min. Rill and interrill erosion rate was measured using soil loss amount per flume area and rainfall duration. Based on the results, both rill and interrill erosion rate were significantly varied among the soils textures (P<0.001). Silt loam was the most susceptible soil to rill erosion (0.22 g m-2 sec-1) and interrill erosion (0.15 g m-2 sec-1), whereas sand didn’t appear any soil loss by these water erosion types. The compression of soil loss resulted by rill and interrill erosion among the soil tectures showed that rill erosion rate for sandy clay loam, silt loam, loam and sandy loam was 3.2, 1.4, 1.1 and 2.8 times higher than interrill erosion rate, respectively. These differences were statistically significant. Silt content was the major factor controlling soil loss difference in these soils. This study revealed that the study semi-arid soils having higher silt content appears also higher rill erosion rate than interrill erosion rate.
A. Motamedi, M. Galoie,
Volume 25, Issue 2 (9-2021)
Abstract
The annual soil erosion in different regions of the world has been estimated using various empirical and numerical methods whose accuracy is very dependent on their utilized parameters. One of the most common methods in the evaluation of the mean annual soil erosion especially in sheet and furrow regions is the USLE method. In this relationship, almost all factors that normally affect the soil loss process such as land cover, slope, precipitation, soil type, and support practice parameter of soil have been employed but, in this research, it was shown that the accuracy of this method in mountainous areas covered by rock and snow is somewhat low. To do this, a part of the Tibet plateau in China, where observation soil loss data were available, was selected for investigation. To implement the numerical and analytical analysis, many maps including DEM, NDVI, orientation, soil type, mean monthly and annual precipitation for 30 years were collected. For increasing the accuracy of the model, the cover management parameter was extracted from high accuracy NDVI maps and all USLE parameters were calculated in ArcGIS. The final results were shown that the amount of annual soil loss which was estimated by the USLE method is more than the observed data which were collected by Chinese researchers. This is because the large areas of the study area are covered by lichen and snow where soil loss due to the erosion process is very low but these regions cannot be recognized from NDVI maps. Also, the analysis of the NDVI maps was shown that the relationships of Fu, Patil, and Sharma were not suitable for soil loss estimation in elevated mountainous areas. If the other relationships such as Lin, Zhu, and Durigon are used for the regions with a height of more than 5500 m, a new correction coefficient needs to be used for the C factor which was calculated as 0.2 for the study area.
M.m. Matinzadeh, J. Abedi Koupai, M. Shayannejad, A. Sadeghi-Lari , H. Nozari,
Volume 25, Issue 4 (3-2022)
Abstract
Using water and fertilizer management at the farm level can be increased water use efficiency and reduce the volume of drainage water, fertilizer losses, and other pollutants in farmland with deep underground drains such as Khuzestan agro-industrial Companies. In the present study, a comprehensive simulation model for the water cycle and the nitrogen dynamics modeling was used for water and fertilizer management modeling on farmland of sugarcane in Imam Agro-Industrial Company using a system dynamics approach. To reduce irrigation water consumption and nitrogen fertilizer losses, five different scenarios were considered including four scenarios of water management consist of 5, 10, 15, and 20 percent reduction in the amount of irrigation water (I1, I2, I3, and I4) compared to the current situation of irrigation in Imam agro-industrial Company (I0), and one scenario of integrated water and fertilizer management (20% reduction in the amount of irrigation water and urea fertilizer 210 Kg/ha, I4F). The results of modeling showed that the scenario of I4F caused to reduce 31, 70, 71, 70, and 85 percent of the cumulative volume of drainage water, cumulative nitrate and ammonium losses, total losses of cumulative nitrate, and ammonium by tile-drain and cumulative losses of denitrification process, respectively. Thus, the implementation of this scenario, not only saves water and fertilizer consumption but also reduces environmental pollution effectively. So the scenario of I4F (amount of irrigation water for six months 2656 mm and urea fertilizer 210 Kg/ha) is recommended for sugarcane in the Imam agro-industrial Company.
N. Pourabdollah, J. Abedi Koupai, M. Heidarpour, M. Akbari,
Volume 25, Issue 4 (3-2022)
Abstract
In this study accuracy of the ANFIS and ANFIS-PSO models to estimate hydraulic jump characteristics including sequence depth ratio, the jump length, the roller length ratio, and relative energy loss was evaluated in stilling basin versus laboratory results. The mentioned characteristics were measured in the stilling basin with a rectangular cross-section with four different adverse slopes, four diameters of bed roughness, four heights of positive step, three Froude numbers, and four discharges. The average statistical parameters of NRMSE, CRM, and R2 for estimating hydraulic jump characteristics with the ANFIS model were 0.059, -0.001, and 0.989, respectively. While, the mean values of these parameters for the ANFIS-PSO model were 0.185, 0.002, and 0.957, respectively. The results indicated that these models were capable of estimating hydraulic jump parameters with high accuracy. However, the ANFIS model was moderately more accurate than the ANFIS-PSO model to estimate the sequence depth ratio, the jump length, the roller length ratio, and relative energy loss.
A. Motamedi, J. Abedi-Koupai, A.r. Gohari,
Volume 26, Issue 2 (9-2022)
Abstract
Water scarcity and lack of soil fertility are two major problems in the agriculture sector. This study aimed to use Azolla anzali and Lemna minor as a cover for a free surface of the water since not only do they have the potential to reduce evaporation, but they can also produce green fertilizer. Therefore, a completely randomized design experiment with 4 treatments (Azolla anzali, Lemna minor, combination of Azolla anzali+ Lemna minor and control) was performed with three replications. The surface of the reservoirs was covered with the mentioned plants and the changes in water height were measured every other day and the amount of nutrients (nitrogen and phosphorus) of the plant tissue was measured three times at the beginning, middle, and end of the period. Eventually, water loss in tanks containing Lemna, Azolla, and Lemna+ Azolla, was 39, 33.2, and 28.7% less than the control tank. The highest amount of nutrients in plant tissue was observed in Lemna, Azolla+ Lemna, and Azolla treatments, respectively. Although the amount of nutrients in the combined treatment was not higher than that of Lemna more biomass was produced, which means it can provide more fertilizer. Finally, the combined treatment of the two plants is a more suitable option to be used.
A. Balvaieh, L. Gholami, F. Shokrian, A, Kavian,
Volume 26, Issue 4 (3-2023)
Abstract
Changes in nutrient concentrations of soil can specify optimal management of manure and prevent environmental and water resources pollution. The present study was conducted with the objective of changing macronutrients concentrations of Nitrogen, Phosphorus, and Potassium with amendments application of polyvinyl acetate, bean residual, and a combination of polyvinyl acetate + bean residual for time periods of one, two, and four months. The results showed that the application of soil amendments had various effects on changing Nitrogen, Phosphorus, and Potassium. The maximum amount of Nitrogen related to the treatment of bean residual at the time period of four months before simulation (with a rate of 44.62 percent) and minimum amount of nitrogen related to Polyvinyl acetate treatment at the time period of one month (with a rate of -1.92 percent). The minimum rate of Phosphorus was measured at the treatment of bean residual at the time period of one month before simulation (with a rate of 0.95 percent). The maximum amount of Potassium related to the treatment of Polyvinyl acetate at the time period of four months before simulation (with a rate of 189.35 percent) and the minimum amount of Potassium related to the combination of bean residual + Polyvinyl acetate at the time period of one month after simulation (with a rate of 40.66 percent). Therefore, the application of amendments has various effects on changing soil macronutrients at different time periods.
A.r. Vaezi, S. Rezaeipour, M. Babaakbari, F. Azarifam,
Volume 27, Issue 3 (12-2023)
Abstract
Improving soil physical properties and increasing water retention in the soil are management strategies in soil and water conservation and enhancing crop yield in rainfed lands. This study was conducted to investigate the role of tillage direction and wheat stubble mulch level in improving soil physical properties in rainfed land in Zanjan province. A field experiment was done at two tillage directions: up to the downslope and contour line, and five stubble mulch levels: zero, 25, 50, 75, and 100% of land cover equal to 6 tons per hectare. A total of 30 plots (2 m×5 m) were created. The results indicated that water infiltration and water content were considerably affected by tillage direction, whereas its effect on water holding capacity was not significant. This physical property of the soil was influenced by the inherent properties of the soil, including particle size distribution. The change of up to down tillage direction to the contour line increased soil infiltration to 11% and water content to 6%. The physical soil properties were wholly influenced by mulch consumption. Soil water content increased in mulch treatments along with water holding capacity and infiltration rate. The highest volumetric water content was at 100% mulch level (10.62%) which was 11% more than the control treatment. However, there was no significant difference between 100% and 75% mulch treatment. This revealed that the application of 75% stubble mulch in contouring tillage is a substantial strategy for improving soil physical properties and controlling water loss in rainfed lands of semi-arid regions.
