Soil science
Kh. Salarinik; M. Nael
Abstract
IntroductionLarge amounts of agricultural waste such as straw, leaves and pulps, with high nutritional value are produced every year. Grape pomace (GP) is rich in macro- and micro-nutrients and can be used as a soil amendment. However, due to its slow decomposition rate and the spread of diseases and ...
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IntroductionLarge amounts of agricultural waste such as straw, leaves and pulps, with high nutritional value are produced every year. Grape pomace (GP) is rich in macro- and micro-nutrients and can be used as a soil amendment. However, due to its slow decomposition rate and the spread of diseases and pests, it should not be applied directly to the soil. Therefore, GP is composted in combination with other wastes. There is not enough information about the composting of GP and the effect of the produced composts on soil fertility in Iran. Hence, the aims of this study were twofold: to explore the impact of various GP composts on both soil fertility and spinach yield, relative to two levels of urea fertilizer, through a pot experiment conducted over two consecutive cultivation seasons; to categorize soil treatments based on fertilization regimes and timing (season), thus elucidating any patterns or trends in the observed effects. Materials and MethodsTo investigate the effects of GP composts on soil fertility and spinach (Persius hybrid) yield, was conducted as a randomized complete block design with eight compost treatments, two levels of urea fertilizer (46%), and a control treatment (C0), in three replications and two continuous cropping seasons (spring and fall). Compost treatments included: high grape pomace (HG) (60-63%) with chickpea straw and alfalfa (HG-Ch-A), high GP with chickpea straw and sugar beet pulp (HG-Ch-B), high GP with alfalfa and sugar beet pulp (HG-A-B), high GP combined with chickpea straw, alfalfa, and sugar beet pulp (HG-All); four other compost treatments included low level of grape pomace (LG) (37-42%) combined with other residues/wastes similar to the first four treatments (LG-Ch-A, LG-Ch-B, LG-A-B, and LG-All). Urea treatments included: 150 kg per hectare (C150) (two-step top dressing) and 500 kg per hectare (C500) (three-step top dressing). A sandy loam soil was used for this experiment. The composts were separately mixed into the soil at a rate of 2% (by weight(. The first crop was grown for 50 days in May 2018 and the second crop was grown for 45 days in September 2018. In both seasons, the fresh and oven-dried weigh of spinach shoot and root were determined. Also, total concentration of K, Na, Ca, Mg, P, Fe, Zn, Cu, and NO3- were measured in spinach to determine the amount of soil elements taken up by the crop. In both seasons, soil pH and EC, and contents of soil organic carbon (OC), active carbon (AC), total nitrogen (TN), NO3-, NH4+, and exchangeable K, Ca, Mg, and Na, as well as available forms of P, Fe, Cu, and Zn were determined. One-way ANOVAs were applied separately to spring and fall data, and mean comparisons were made using Duncan's test at 0.05% level. To determine the similarities and dissimilarities of the different treatments based on their effect on soil characteristics, cluster analysis was performed on all soil characteristics that showed significant differences between treatments. Results and DiscussionIn both cultivation periods, TN levels exhibited no significant variance across treatments. Notably, the highest potassium (K) levels were consistently observed in the HG-All and LG-All treatments, while the lowest K levels were consistently recorded in the C0, C150, and C500 treatments. In the initial cultivation period, no notable differences were observed between the C0, C150, and C500 treatments, except for potassium (K) and ammonium (NH4+), with significantly higher levels detected in the C0 treatment. Conversely, during the second cultivation period, significant disparities were observed among the C0, C150, and C500 treatments solely in terms of nitrate (NO3-) content, with notably higher nitrate levels detected in the C150 and C500 treatments. Through cluster analysis, all treatments from both cultivation periods were categorized into five distinct groups. Specifically, the C0, C150, and C500 treatments for each season were consistently grouped together, respectively, into groups one and two. All compost treatments of each season, except the HG-All treatment in the spring cultivation, were grouped into one class. In the second cultivation, the HG-Ch-A showed significantly higher EC than all treatments, except the HG-Ch-B. The LG-A-B treatment showed the highest amount of OC and C/N (in both cultivations), and NH4+ and Cu (in the second cultivation). The HG-Ch-A and HG-Ch-B treatments increased TN, P, K, Mg, OC, and AC in the second cultivation compared to the first. The amounts of all macronutrients and micronutrients, except Fe and Ca, increased in the compost treatments compared to the control and chemical treatments. In addition, an increase in EC was observed in the compost treatments compared to the control and chemical treatments, and an increase in pH compared to the C500 treatment. In the first cultivation, the LG-Ch-A and C500 treatments had significantly higher yields than the control. In the second cultivation, the LG-All, HG-All, HG-Ch-A, and LG-A-B treatments were the best compost treatments, while the LG-Ch-B and HG-Ch-B treatments were the weakest treatments in terms of soil fertility and plant yield. In both seasons, the absorption of elements by spinach depended on multiple factors, including the element type, its available content in the soil, its initial content in the composts (or fertilizer), soil pH, and yield. ConclusionThe application of GP composts over two consecutive growing seasons increased the levels of nitrogen, phosphorus, potassium, magnesium, zinc, copper, active carbon and organic carbon in the soils. These results are very important as magnesium, copper and zinc are rarely applied by farmers. In contrast, depletion of all elements, except organic carbon, occurred in the control and chemical fertilizer treatments due to plant uptake of elements. The combination of chickpea straw with sugar beet pulp is not recommended for the production of GP compost, especially at low GP levels, due to its minimal effect on soil fertility and plant yield. Despite the positive effect of the GP composts in increasing soil fertility, the continuous application of large amounts of these composts is not recommended in the arid regions due to the increase in soil EC and pH. The difference between the compost treatments after two applications of GP composts was less than after one application; these results were confirmed by cluster analysis, in the sense that all compost treatments in the second season were placed in one cluster.
E. Hashempour; M.B. Farhangi; N. Ghorbanzadeh; M. Fazeli Sangani
Abstract
Introduction: Due to the increasing development of edible oil processing industries, large amounts of wastewater and solid wastes (SW) are inevitable in these industries. Organic wastes can be used as soil conditioners in agriculture due to the high content of organic matter and nutrient loads. Phosphorus ...
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Introduction: Due to the increasing development of edible oil processing industries, large amounts of wastewater and solid wastes (SW) are inevitable in these industries. Organic wastes can be used as soil conditioners in agriculture due to the high content of organic matter and nutrient loads. Phosphorus solubilizing bacteria including Bacillus spp., Pseudomonads and Rhizobium spp. can release phosphorus from insoluble organic and mineral sources in soil. Most soils in the semi-arid regions, including southern parts of Guilan province, have low organic matter content and do not support plant cultivation due to the low fertility and instability of soils. Hence, industrial wastes can be applied as a suitable and low-cost source of organic materials and nutrients in these soils. As phosphorus is one of the most important essential nutrients in plant nutrition which is also present in oil refinery soild wastes and P solubilizing bacteria can release phosphorus from the organic phase of the wastes and make it available in the soil solution, this study aimed to investigate the available phosphorus (Pava) content of soil after simultaneous addition of olive refinery-solid wastes and P solubilizing Bacillus spp.
Materials and Methods: the solid waste obtained from Ganje Rudbar oil refinery plant (located in Rudbar, Guilan province) and a soil sample was collected from a surface layer (0-30 cm) of a pasture, located in Lowshan area (Guilan province). A native strain of Bacillus sp. was isolated from the sampled soil based on its P-solubilizing ability in Sperber medium. An indicator strain, Bacillus persicus was also included in the experiments. P-solubilizing ability of the indicator strain was also evaluated in Sperber medium. The experiment was conducted in a completely randomized design based on factorial arrangement and three replications. Factors included three levels of solid waste (0, 2 and 4%), three levels of inoculated bacteria (no bacteria, native Bacillus sp. and Bacillus persicus) and eleven sampling times (0, 2, 7, 14, 28, 42, 56, 86, 116, 146, and 176 days). Different levels of solid waste were added to the soil, inoculated with bacteria (106 cell/g), and incubated at laboratory condition (~25 ºC) for six months. The moisture content of the soil mixtures fixed around 0.7 FC and kept constant during the incubation period. Sampling was done at desired times. The pH, organic carbon (OC), soil Basal Respiration (BR), available phosphorus concentration (Pava), and phosphatase enzyme activity were measured in soil samples. Data analysis and means comparison were done by Duncans’ test using SAS software package.
Results and Discussion: The studied soil was loam in texture, and had slightly alkaline pH, moderate Pava, and low OC content. The studied solid waste contained considerable OC and total P load. The effect of solid waste (SW), bacteria, sampling time and their interactions were significant on most of the measured characteristics (p < 0.05). SW application decreased soil pH and mixtures inoculated with native Bacillus sp. had lower pH values compared to those inoculated with Bacillus persicus, probably due to the greater effect of Bacillus spp. on SW decomposition compared with B. persicus. The highest average BR was attained in mixtures contained 4% SW which was 1.24 and 1.73 times greater than that in mixtures contained 2 and 0% SW, respectively. While the effect of SW on soil BR was obvious, bacteria inoculation had different impact on soil organic material decomposition and the lowest BR was measured in soil (0% SW) inoculated with Bacillus persicus. OC content of mixtures increased with SW application. The highest OC level (3.21 g 100g-1) was obtained in uninoculated mixture contained 4% SW, which was significantly greater than OC levels in mixtures inoculated with bacteria (p < 0.05). The lowest OC level (3.21 g 100g-1) was observed in uninoculated soil (0% SW). SW application significantly increased Pava. The greatest Pava concentration (142.77 mg Kg-1) was attained in uninoculated mixture contained 4% SW which was not significantly different from Pava concentration in 4% SW-mixture inoculated with native Bacillus sp. (P > 0.05). In control treatments (0% SW), Bacillus persicus was efficient in P release from soil native organic carbon and/or phosphate minerals. However, among the soils contained 2% SW, those inoculated with native Bacillus sp. had the highest Pava concentration. The average Pava concentration in the 4% SW-mixtures was 136.33 mg Kg-1 which was 3.5 times greater than that in control treatment (0% SW). Although soil Pava was related to phosphatase enzyme, this enzyme activity was not affected by treatments. In the P-releasing trend, it was found that 4% SW-mixtures had the highest Pava concentration after 6 months of incubation, and bacteria inoculation made the P-release trend to be flatter compared to control.
Conclusion: The application of oil refinery plant-solid waste improved the basal respiration of the studied soil and increased available phosphorus concentration. The comparison of applied solid waste levels showed that the inoculation of soil with Bacillus bacteria had a positive effect on available phosphorus concentration only at 2% solid waste level.
Ladan Heydari; Javad Hamzei; Tahmeineh Ghytasi Ranjbar; Somayeh Bahramian Ragheb; Fatemeh Madineh Khorrami
Abstract
Introduction: Stability of soil aggregates is a result of complex physical, chemical and biological processes in the soil. In many studies, organic matter has been studied as a major factor in formation of aggregates and the effects of symbiosis between mycorrhizal fungi and bacteria largely ignored, ...
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Introduction: Stability of soil aggregates is a result of complex physical, chemical and biological processes in the soil. In many studies, organic matter has been studied as a major factor in formation of aggregates and the effects of symbiosis between mycorrhizal fungi and bacteria largely ignored, however these microorganisms have a great effect in the formation of the aggregates. Plant roots provide a suitable habitat for the activity of many soil microorganisms. In this regard, the symbiosis of plant roots with fungi is one of the most common and long-lived symbiotic relationships that are found in most ecosystems. On the other hand, biological fertilizers can improve soil aggregation through influence the growth of root and plant. Despite the significant effect of fungi and bacteria on the stability of the soil structure, the effect of arbuscular mycorrhizal fungi species Glomus mosseae and Rhizobium species Mesorhizobiumon caesar on the soil structure has been rarely investigated. Therefore, the aim of this study was to evaluate the effect of chickpea inoculation with Rhizobium (Mesorhizobium caesar) and mycorrhizae (Glomus mosseae) on soil structural stability and aggregates size distribution under both greenhouse and field conditions.
Materials and Methods: The present study was conducted as a randomized complete-block design with three replications in both greenhouse and field conditions. The treatments under field condition were mycorrhizal fungus (Glomus mosseae), Rhizobium (Mesorhizobium caesar), mycorrhizae – rhizobium combined treatment and a control (no inoculation). In the greenhouse condition, sterilized mycorrhiza background material and without plant (without inoculation) treatments were also added. Chickpea was planted at both conditions. Soil sampling was carried out after harvesting. The stability of aggregates using wet sieving method and soil organic carbon content were investigated.
Results and Discussion: Greenhouse study results showed that mycorrhizae treatment significantly increased the mean weight diameter of the aggregates by 51.6% and 189.1%, in comparison with the control (without inoculation) and control- without plant (without inoculation), respectively. This treatment increased macro aggregates and decreased the fine aggregates. In the greenhouse condition, soil organic carbon content had a high correlation with the mean weight diameter of the aggregates (R2 = 0.53) and mycorrhizal treatment increased organic carbon content from 0.73% in the control (without plant) to 1.02%. However, the mycorrhizae – rhizobium combined treatment had less effect on the stability of the aggregates than their single effects. The mass of aggregates of 1–2 mm are more sensitive to short-term management. In the greenhouse condition all the three biofertilizer treatments significantly increased the mass of the aggregates of 1-2 mm in comparison with the control treatment without plant (without inoculation). On the other hand, the mean comparison results showed that there was no significant difference between the sterilized mycorrhizal background and the control without plant (without inoculation). This may be due to the lower organic matter content in these two treatments compared to others. In the greenhouse condition, increasing the mass of coarse aggregates of 4-8 mm in diameter indicates the suitability of soil structure. On the other hand, aggregates coarser than 0.25 mm are considered as coarse and stable aggregates. It can be concluded that the application of mycorrhiza and rhizobium increased soil structural stability through the increase of the mass of these classes of the aggregates (2-4 and 4-8 mm), probably by affecting the length and volume of the root and plant yield. Under the field condition, the treatments had no impact on the mass of the aggregates in different size classes.
Conclusion: Bacteria and fungi can be effective factors in improving soil structure through increasing organic carbon in soil. The results of the present study indicated that aggregate stability was affected by biological fertilizer treatments under greenhouse condition so that the treatments containing biofertilizers increased soil aggregate stability and improved the soil structure that was probably due to increasing plant yield and root. Also, the less effect of biofertilizers on the stability of the aggregates and the increase of coarse aggregates under the field condition can be due to the uncontrolled climatic conditions compared to the greenhouse and the short duration of the study. In recent decades, the physical and chemical properties of soils have changed due to the use of chemical inputs in agricultural lands.The use of biological and organic fertilizers is an appropriate solution to these problems. It is recommended further study on the efficacy of other species of mycorrhizal fungi and rhizobium bacteria in improving soil physical and chemical quality, especially at the field scale. Also, considering the implementation of this project in the field condition, it is suggested to study the physical, mechanical and chemical properties of soil in the long term.
N. Moradi; M.H. Rasouli-Sadaghiani; E. Sepehr
Abstract
Introduction: Biochar is a material produced from organic matters under high temperature and low oxygen conditions. In recent years, scientific attention has been focused on its effects on soil amendment and ecological restoration.Due to its properties related to surface area and porosity, bulk density, ...
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Introduction: Biochar is a material produced from organic matters under high temperature and low oxygen conditions. In recent years, scientific attention has been focused on its effects on soil amendment and ecological restoration.Due to its properties related to surface area and porosity, bulk density, nutrient content, stability, cation exchange capacity (CEC), pH value, and carbon content, biochar has the potential to improve physical and chemical soil properties and thus improve crop productivity and contribute to carbon sequestration. Biochars can have very different properties depending on the feedstock they are produced from and the pyrolysis conditions used to generate them.Biochar retains nutrients for plant uptake and soil fertility. The infiltration of harmful quantities of nutrients and pesticides into ground water and the runoff that erodes the soil and enters into the surface waters can be limited with the use ofbiochar. The actual effects of biochar on soil properties depend on the soil type and the plant species grown on the area of application, as well as biochar type and application rate.The aim of this study was to evaluate the effect of the biochar types and rates on some soil properties and nutrient availability in a calcareous soil.
Materials and Methods: An incubation experiment was conducted in a completely randomized design with three replications. The treatments were three type of biochar (apple pruning wastes, grape pruning wastes and wheat straw), and five biochar rates (0, 1, 2, 4 and 8% w/w). Biochars used in the experiment wereproduced at the final temperature of approximately 350°C for almost 3 hours. The biochars were ground and sieved over 1 mm sieve for the incubation experiment.100 g of soil sample was weighed into polyethylene pots and then thoroughly mixed with 1, 2, 4 and 8 g of the biochar samples. Soil controls were run without any amendment. Distilled water was added to the soil–biochar mixtures (soil samples) in order to keeptheir moisture content to 60% of their water-holding capacity. The incubation was carried out in a controlled incubation chamber at 25oC for incubation in aerobically controlled non-leached conditions during 8 weeks.After 60 days, the samples were dried andsoil pH and electrical conductivity (EC) were determined in 1:5 soil to water extracts. Also, to determine mineral N, the soil samples with biochar were extracted with 2 M KCl. Organic matter was determined by dichromate oxidation. Soil extractable P and K were extracted with 0.5 M NaHCO3 (ratio 1:10) (Olsen-P) and 1 N NH4Ac (1:20) (NH4Ac-EK), respectively. DTPA-extractable Fe, Mn, Cu, and Zn were analyzed by atomic absorption spectrometry method (Shimadzu AA-6300).
Results and Discussion: The results indicated that adding biochar changed some soil properties such as soil organic carbon, pH, electrical conductivity and the availability of some macro and micro nutrients. These changes were also more evident with increasingin the rate of biochar. Soil organic carbon (SOC) contentsin the amount of 8% apple pruning wastes, grape pruning wastes and wheat straw biochar were 3.78, 3.80 and 5.24 times more than control, respectively. Available potassium and phosphorus increased further in derived biochar from wheat straw in the amount of 8% compared with apple pruning and grape pruning wastes. Soil available potassium in wheat straw biochar was 2.19 and 1.88 times higher than apple pruning and grape pruning wastesbiochars, respectively. Wheat straw biochar greatly increased soil EC compared to control, and a higher biochar addition finally resulted in a higher value of soil EC. Also, the mineral – N, comprising of ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N), concentrationshowed significant reduction when different rates of biochar were added to the soil. Increase in the rate of applicationmarkedly reduced the concentration of both NH4-N and NO3-N. Wheat straw biochar significantly reduced available iron. Also, soil available copper significantly decreased by increasing the rate of biochar. But, soil available manganesesignificantly increased by increasing the rate of biochar. The type and rate of studied biochars had no significant effect on available Zn.
Conclusions: Generally, the soil organic carbon (SOC) markedly increased with an increase in rate of application ofbiochar during the 60 days of incubation. This suggests that the biochar has great potential for carbon sequestration in soil.In conclusion, it became clear that in order to allow for accurate prediction of the effects ofbiochar on soil characteristics and nutrient availability, a deeper understanding of interactions between soil type, biochar production method, biochar feedstock, application rate and field crops is essential. Further research is needed to determine long term impacts of biochar on these soils.
A. Baghdadi; M. Balazadeh; A. Kashani; F. Golzardi
Abstract
Introduction In recent years, continuous operation and disrespect to crop rotation has caused the destruction of soil organic matter so that organic matter in arid and semiarid areas of the country is at least possible and According to the hazards and contamination of chemical fertilizers usage, need ...
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Introduction In recent years, continuous operation and disrespect to crop rotation has caused the destruction of soil organic matter so that organic matter in arid and semiarid areas of the country is at least possible and According to the hazards and contamination of chemical fertilizers usage, need to reduce consumption of these inputs and find ecological methods to provide Nutritive requirements for crops, to maintain and increase soil fertility has felt. One of the these ways is using of the appropriate pre-sowing plants, by backing pre-sowing plants (green manure) in soil causes to increase the carbon and organic matter, total nitrogen and soil fertility that this phenomenon occurred as a result of microbiological processes and it causes to releasing the nutrients for the plants. Therefore, this study aimed to investigate of integrated crop management on characteristics of soil nutrients and nitrogen mineralization during the period after adding the green plants remains was conducted in Karaj.
Materials and Methods This research is performed during growing season 2013-14 at the Agricultural Research Station of Islamic Azad University of Karaj, Iran. The experiment was conducted as a split plot based on a randomized complete block design with four replications. Main factors include pre-sowing treatments in 4 levels (Perko PVH, Buko, Cattle manure and Fallow) and sub factors also included nitrogen levels (120 and 240 and 360 kg ha-1, utilized urea source). Perko PVH and Buko belong to Brassicaceae family that if they back to the soil they can increase the oraganic matter. Pre-sowing of Perko PVH and Buko were planted in middle of March. Pre-sowing plants before that they going to flowerer stem coincide with the end of the vegetative stage, two weeks before the corn planting they was picked from the soil surface and the remains mixed with soil by rotavator machine. In order to apply cattle manure application in intended plots the amount of 7 ton ha-1 was given to the soil before the corn planting. On 6 July 2014 corn planting was done by pneumatic machine. Nitrogen fertilizer in 3 times was separated and as a topdressing form in the amount of 10, 70 and 20 percentage in the five-leaf stage, Stem elongation and tasselling emergence stage Were applied. After harvesting corn silage, Samples randomly from zero to 30 and 30 to 60 cm depths in each plot were taken and mixed together. Soil samples separately were dehumidified by air and were passed from 2 mm sieve. Organic carbon of soil samples by oxidation in the presence of potassium dichromate and concentrated sulfuric acid (Hesse, 1971) and total nitrogen were determined by Kjel (Hesse, 1971 ) and for measuring of soil mineral nitrogen, of samples tested by the 2 mol KCl solution the extraction and ammonium nitrate samples were measured by means of distillation and titration with HCl .Data analyses are done by using SAS (Version 9.1.3) statistic software mean comparison was done using the LSD test at probability level of 5%.
Results and Discussion Analysis of variance illustrated that the effect of pre-sowing on organic carbon, total nitrogen, nitrate nitrogen and soil ammonium nitrogen in 5% probability level was significant, so that in all traits, Perko PVH and Buko were the best treatments than the fallow and animal manure treatments. The effect of nitrogen levels on all traits were significant in 1% probability level, so that by increasing the nitrogen usage, the rate of these traits increased. Interaction between pre-sowing treatments and nitrogen levels on soil organic carbon, total nitrogen, nitrate nitrogen and ammonium nitrogen in the soil were highly significant in 1% probability level; so that Perko PVH pre-sowing treatment and consumption of 360 kg ha-1 nitrogen of urea source, the highest values of these traits created. The highest percentage of soil organic carbon affected by Perko PVH pre-sowing treatment and rate of 360 kg ha-1 nitrogen in a rate of 1.08% and the lowest percentage of soil organic carbon was related to cattle manure treatment and rate of 120 kg ha-1 nitrogen in a rate of 0.58. The highest percentage of total soil nitrogen affected by Perko PVH pre-sowing treatment and rate of 360 kg ha-1 nitrogen in a rate of 0.102% and the lowest percentage of total soil nitrogen was related to cattle manure treatment and rate of 120 and 240 kg ha-1 nitrogen in rates of 0.052 and 0.047.
Conclusions By the results of this study, the effect of integrated crop management with integrated application of organic fertilizers with nitrogen fertilizer, the cause of the soil Chemical properties and soil fertility is increased. Hence the use of organic fertilizers, meanwhile the significant reduction in the use of nitrogen fertilizer can reduce their environmental impacts. The result of study indicated that pre-sowings of Perko PVH and Buko had a positive and significant effect on soil chemical parameters and soil chemical characteristics reaction on pre-sowing yield is different. In general can say that planting the pre-sowing plants and return the remains to soil causing the protection and increasing soil fertility and consequently causing the Increase the quantity and quality of the crop and can be considered as a one way to achieve sustainable agriculture.
P. Mohajeri; P. Alamdari; A. Golchin
Abstract
Introduction: Topography is one of the most important factors of soil formation and evolution. Soil properties vary spatially and are influenced by some environmental factors such as landscape features, including topography, slope aspect and position, elevation, climate, parent material and vegetation. ...
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Introduction: Topography is one of the most important factors of soil formation and evolution. Soil properties vary spatially and are influenced by some environmental factors such as landscape features, including topography, slope aspect and position, elevation, climate, parent material and vegetation. Variations in landscape features can influence many phenomena and ecological processes including soil nutrients and water interactions. This factor affects soil properties by changing the altitude, steepness and slope direction of lands. In spite of the importance of understanding the variability of soils for better management, few studies have been done to assess the quality of soils located on a toposequence and most of these studies include just pedological properties. The aim of this study was to investigate physical and chemical properties of soils located on different slope positions and different depths of a toposequence in Deilaman area of Gilan province, that located in north of Iran.
Materials and Methods: The lands on toposequence that were same in climate, parent material, vegetation and time factors but topographical factor was different, were divided into five sections including steep peak, shoulder slope, back slope, foot slope and toe slope. In order to topsoil sampling, transverse sections of this toposequence were divided into three parts lengthways, each forming one replicate or block. 10*10 square was selected and after removing a layer of undecomposed organic residues such as leaf litter, three depths of 0 to 20, 20 to 40 and 40 to60 cm soil samples were collected. physical and chemical characteristics such as soil texture, bulk density, aggregate stability, percent of organic matter, cation exchange capacity, available phosphorous and total nitrogen were measured.
Results and Discussion: The results showed that, because of high organic matter content and fine textured soils on the lower slope positions including foot slope and toe slope, aggregate stability, cation exchange capacity, available phosphorous and total nitrogen were maximum in these positions, whereas, bulk density had a reverse trend and was higher in the upper slope positions than the lower slope positions. The high content of organic carbon, phosphorus and total nitrogen in the soil of foot and toe slope positions, can be attributed to soil erosion and transferred from top of the slope and their accumulation in these situations. The results also revealed that, with increasing depth, aggregate stability, organic carbon content, cation exchange capacity, available phosphorous and total nitrogen content of soils decreased, whereas, clay content and bulk density had a reverse trend and increased with increasing the depth. Reducing the amount of organic carbon with increasing depth was because of the remains of plants and roots in the surface horizons and the presence of more organic carbon. Since phosphorus and nitrogen in the soils are highly dependent on organic matter, Thus, changes in these indicators are mainly obeys from this materials.
Conclusion: In general, it became appears from this study, that the topography factor had important effect on studied soil properties. The changes observed in the quality of soils located on different slope positions can be attributed to the differences of the soil in erosion rate and moisture content and different sediment receptions in different positions of toposequence as affected by the amount and distribution of rainfall. Considering the effect of the position of the landscape on the physical and chemical properties of soil, recommended analysis of the landscape is better to be done in the sustainable land management and also for soil and water conservation programs. Because of the different management practices in different parts of landscape is difficult and perhaps impossible, in order to maintain soil, conservation management must be done based on soil quality in areas with maximum damage and minimum quality.
Ahmad Gholamalizadeh Ahangar; F. Sarani; M. Hashemi; A. Shabani
Abstract
Knowledge of organic carbon spatial variations in different land uses will help to interpret and simulate the behavior of terrestrial ecosystems facing environmental and climate changes. The purpose of this study is comparing regression, geostatistics and artificial neural network (ANN) methods for predicting ...
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Knowledge of organic carbon spatial variations in different land uses will help to interpret and simulate the behavior of terrestrial ecosystems facing environmental and climate changes. The purpose of this study is comparing regression, geostatistics and artificial neural network (ANN) methods for predicting organic carbon content in 192 samples of surface soil (0 to 30 cm) of Sistan plain (Miankangi region). In this study, Only 25% of organic carbon variations were explained by variables used in linear regression model in the study area (R2= 0.25). Moreover, simple co-kriging (with clay as co-variable) which was the best geostatistical method in the current study, predicted organic carbon content weakly (R2= 0.23 and RMSE= 0.127). However, using latitude and longitude parameters, ANN performed much better than linear regression and geostatistical methods for predicting organic carbon content (R2= 0.79 and RMSE= 0.044).
M. Mahmoodabadi; O.L. Rashidi; M. Fekri
Abstract
This study focused on the effect of organic manures as well as potassium fertilizer on some soil properties and onion yield at the field condition. The experiments were carried out as factorial in a randomized complete block design with three replications. The treatments were poultry manure (10 t ha-1), ...
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This study focused on the effect of organic manures as well as potassium fertilizer on some soil properties and onion yield at the field condition. The experiments were carried out as factorial in a randomized complete block design with three replications. The treatments were poultry manure (10 t ha-1), alfalfa residue (10 t ha-1) and control each together with two levels of potassium fertilizer as K2O (0 and 250 kg ha-1). The results showed that application of poultry manure and alfalfa residue resulted in yield increasing about 57.7 and 40.9 % in comparison to the control, respectively. On average, the onion yield for the potassium treatment was 7.8 % higher than for the untreated one. The application of poultry manure and alfalfa residue increased final infiltration rate 73.2 and 56.1 %, respectively. Inversely, potassium fertilizer caused a significant reduction in the final infiltration rate. Moreover, application of organic manures particularly poultry manure, significant increases in saturated moisture, porosity, EC, organic carbon and available phosphorous and decrease in bulk density and pH was observed, while potassium only increased soil EC, significantly. Application of poultry manure and alfalfa residue increased soil organic carbon 129.8 and 80.2 % and available phosphorous 104.8 and 51.9 %, respectively. Among different soil properties, organic carbon showed the highest influence on yield increase.
F. Akbarnejad; A. Astaraei; A. Fotovat; M. Nasiri Mahalati
Abstract
Recently Application of municipal solid waste compost and sewage sludge on the farm land had received considerable attention. These organic wastes provides a valuable source of organic matter and enhances crop yield and soil fertility by improving soil physical, chemical and biological properties. To ...
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Recently Application of municipal solid waste compost and sewage sludge on the farm land had received considerable attention. These organic wastes provides a valuable source of organic matter and enhances crop yield and soil fertility by improving soil physical, chemical and biological properties. To evaluate the influences of municipal solid waste compost (MSWC) and sewage sludge (SS) on chemical properties of soil an experiment was conducted with Municipal solid waste compost at 0, 15, 30 ton/ha (C0, C15 and C30) and sewage sludge at 0, 15, 30 ton/ha (S0, S15 and S30) in a factorial experiment based on completely randomized design with three replications in greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad. Results showed that municipal solid waste compost and sewage sludge and their interaction effects had significant effects on soil chemical properties. With increasing amounts of municipal solid waste compost and sewage sludge, organic carbon and electrical conductivity of soil increased. Portion of Sewage sludge compared to municipal solid waste compost in increasing of organic nitrogen is lower. The most amount of soil organic nitrogen was observed in municipal solid waste treatments. Also use of these wastes together decreased soil acidity.
H. Dehghan Manshadi; M.A. Bahmanyar; A. Lakzian; S. Salek Gilani
Abstract
Sewage sludge with having the organic matter is considered as a source of micro and macro elements. In order to investigate the effect of different levels and period of application of sewage sludge (SS) on organic matter, respiration, and acid and alkaline phosphatase activity, factorial design were ...
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Sewage sludge with having the organic matter is considered as a source of micro and macro elements. In order to investigate the effect of different levels and period of application of sewage sludge (SS) on organic matter, respiration, and acid and alkaline phosphatase activity, factorial design were studied, in 3 replications. Sewage sludge at five levels, (20 and 40 tons of sewage sludge, 20 and 40 tons of sewage sludge + 50 percent of chemical fertilizers (CF) per hectare, without taking sewage sludge) and period of application three levels (two, three and four years) was considered. The results showed that application of SS at all levels, increased soil organic carbon (O.C) and soil microbial respiration and enzyme activity were compared with the controls (p
