Sh. Haghighi; Z. Sharifi
Abstract
Introduction: Calcareous soils are described as soils containing quantities of calcium carbonate which have an enormously effect on the soil properties (physical, consisting of soil water relations and soil crusting, or chemical consisting of the availability of plant nutrients) and plant growth. Calcareous ...
Read More
Introduction: Calcareous soils are described as soils containing quantities of calcium carbonate which have an enormously effect on the soil properties (physical, consisting of soil water relations and soil crusting, or chemical consisting of the availability of plant nutrients) and plant growth. Calcareous soils arise clearly in arid and semi-arid areas due to rare precipitation and little leaching. It has been evaluated that these soils contain over one-third of the world's surface zone and their CaCO3 content ranged from a few to 95%. Calcareous soils faced many challenges such as shortage of organic matter, low structure stability, low water holding capacity, low CEC, high pH, surface crusting and cracking and great infiltration rate which cause loss of essential plant nutrients via leaching or deep percolation. Another problem in calcareous soils is low availability of plant nutrients particularly phosphorous and micronutrients specially zinc, iron and manganese, and a nutritional imbalance between elements such as potassium, magnesium and calcium. Although a calcareous soil is dominated by free lime, it could also incorporate large quantities of iron, aluminum, and manganese. These metals provide more strong sorption sites for phosphorus and are mostly more significant in controlling phosphorus solubility in calcareous soils than calcium carbonate itself. Under such severe conditions, desired yield levels are difficult to attain. Calcareous soils lack the organic matter required for optimal crop yield. Therefore, numerous studies have made efforts to increase the availability of nutrients in the soils through different treatments. Common methods for dealing with these deficiencies, is the use of chemical fertilizers that have the risk of environmental pollution in addition to the high cost and low efficiency. Oxidation of sulfur leads to sulfuric acid formation which can decrease the soil pH and increase dissolution of insoluble soil minerals and release of essential plant nutrients. Furthermore, the addition of organic amendments improves the soil chemical and physical properties, initiates nutrient cycling, and provides a functioning environment for vegetation. Materials and Methods: The objective of this research was to increase solubility of nutrient elements in a calcareous soil considering nine treatments (i.e., control (Blank), Soil + Humic Acid (HA), Soil + Sulfuric Acid (H2SO4 ), Soil + Thiobacillus (T), Soil + Sulphur (Sº), Soil + Sulphur + Thiobacillus (Sº +T), Soil + Vermicompost (VC), Soil + Vermicompost + Thiobacillus (VC+T) and Soil + Sulphur + Vermicompost + Thiobacillus (Sº +VC+T)). The experimental design was factorial arrangement in randomized complete block, with all the treatments replicated three times. All the treatments were incubated under the laboratory condition for 90 days in 25 ± 2 °C and 70% of water holding capacity by distilled water. During the incubation period, the moisture of the samples was kept at 70% FC by daily addition of deionized water based on weight loss. At the end of incubation period the pH value, electrical conductivity (EC), available form of macro elements (K, P and N) and micro elements (Zn, Mn, Fe and Cu) were determined in all treatments by standard methods. Results and Discussion: The results showed that, the soil pH value significantly decreased in Sº+T and Sº+VC+T treatments, in com\pared to the blank. While, the EC of these treatments significantly increased with respect to the blank. The results also showed that most of the treatments have been able to increase the solubility of the nutrients. However, the effect of Sº +VC+T treatment on increasing the availability of studied soil nutrients and decreasing pH value was more significant than the other treatments. Conclusion: Analysis of the results obtained from this study using classical statistic methods showed that applying a single treatment cannot remove all obstacles to increase nutrient availability in calcareous soils. This may be attributed to high buffering capacity of calcareous soils and complexity of factors which control mineral solubility and nutrient availability. While, treatments that simultaneously provide soil organic matter and lower pH (such as Sº+VC+T) can significantly remove barriers to increase nutrient uptake in these soils. As a result, the simultaneous application of organic fertilizers, elemental sulfur and Thiobacillus bacteria can be a promising approach to increase the solubility of nutrients in calcareous soils and to increase the quantitative and qualitative growth of plants in these soils.
Akbar Hassani; Maryam Etemadian; mehdi nourzadeh haddad; Mehrdad Hanifeie
Abstract
Introduction: In calcareous soils of Iran, using fertilizers that reduce soil pH over long periods are prioritized. Reducing pH in calcareous soils increases the concentration of essential nutrients such as phosphorus, iron, zinc, copper and manganese in the soil solution. The use of organic and inorganic ...
Read More
Introduction: In calcareous soils of Iran, using fertilizers that reduce soil pH over long periods are prioritized. Reducing pH in calcareous soils increases the concentration of essential nutrients such as phosphorus, iron, zinc, copper and manganese in the soil solution. The use of organic and inorganic acids in calcareous soils may also have other advantages in addition to gradually decreasing the soil solution pH. The effect of organic and minerals acids on plant growth and uptake of essential nutrients has not been studied. The aim of this study was to evaluate the effect of organic acids like acetic, citric and oxalic acid and mineral acids like sulfuric on the growth of forage corn.
Materials and Methods: The experiment was based on randomized complete block design and carried out in pots in a greenhouse. A calcareous soil with electrical conductivity of 0.86 dS m-1 and organic matter of 4.3 g kg-1 was collected from research farm of University of Zanjan. Treatments were T1 & T2: citric acid with concentration of 5 and 10 mM (C5 & C10), T3 & T4: acetic acid at a concentration of 5 and 10 mM (A5 & A10), T5 & T6: oxalic acid at a concentration of 5 and 10 mM (O5 & O10), T7: mixture of citric, acetic and oxalic acid each at a concentration of 3.33 mM (mix):, T8: sulfuric acid at a concentration of 5 mM (S), and T9: control. Treatments were applied in three stages: immediately after sowing, four-leaf and eight-leaf stages. Irrigation of pots was done with water with EC value of 400 μS /cm. Considering the possible effect of acids on increasing the availability of phosphorus, potassium, iron, zinc, copper and manganese, fertilization was done only based on nitrogen demand and 0.55 g urea was added to each pot (equivalent to 200 kg ha-1) with irrigation water in three steps. The shoots of plant samples were harvested after 50 days and the roots were carefully removed from the soil. Some growth related characteristics such as stem height, fresh weight, dry weight, and moisture content of vegetable tissue were also measured. Concentration of nitrogen, potassium, phosphorous, iron, zinc, manganese and copper in roots and shoots was measured. Translocation factor (TF) indicating the transfer rate of the elements from root to shoot was obtained by dividing the concentration of the element in the shoot by that in the root.
Results and Discussion: The results showed the significant effects of the treatments on the growth factor (fresh weight, dry weight and plant height). The percentage of moisture content was the same in all treatments. Citric acid treatment (T2) significantly increased fresh weight of shoot (18.3 percent) and dry weight (20.9 percent) of the plant. Organic acids also increased the concentration of nitrogen in shoots and roots. The concentration of nitrogen in the shoots was roughly twice as compared with that in the plant root. As for the potassium treatments, except for A10 treatment (T4) (the lowest concentration), other treatments did not show a significant difference with control. The highest concentration of potassium in roots was observed in sulfuric acid treatment (T8). The highest translocation factor of potassium (3.34) was observed in O10 treatment (T6). The results indicated a positive effect of 5 mM citric acid, acetic acid, mix treatment and sulfuric acid on shoot phosphorus and the positive effect of acetic acid and mix treatment on the phosphorus root. Citric acid treatments (T1 and T2) were the most effective treatments in increasing the concentration of iron (289 mg kg-1) in shoots. For roots, C10 treatment (T2) and Mix treatment (T7) showed the highest iron concentration. The highest TF for iron was observed in A10 treatment (T4). Acetic acid treatments (both concentrations), and sulfuric acid were more effective than other treatments and significantly increased the manganese concentration of the shoots. Sulfuric acid also caused a significant increase in the manganese concentration of the root. Acetic acid treatment (T5) showed the highest amount of TF for manganese. The amount of zinc element in shoots and roots was significantly affected by the mix treatment (T7). There was no significant difference between all Cu treatments.
Conclusions: In general, application of citric acid in both concentrations is useful to increase the biological yield and product quantity in maize farms. These treatments increased fresh and dry weight of shoots and roots. Acetic acid seems to improve translocation of elements in plants. The use of other acids is likely to enhance concentration of nutritional elements in roots and shoots.
Sareh Nezami; Mohammad Jafar Malakouti
Abstract
Introduction: Phosphorus (P) and zinc (Zn) fixation by soil minerals and their precipitation is one of the major constraints for crop production in calcareous soils. Recent Studies show that root exudates are effective for the extraction of the large amounts of nutrients in calcareous soils. A part of ...
Read More
Introduction: Phosphorus (P) and zinc (Zn) fixation by soil minerals and their precipitation is one of the major constraints for crop production in calcareous soils. Recent Studies show that root exudates are effective for the extraction of the large amounts of nutrients in calcareous soils. A part of the root exudations are Low Molecular Weight Organic Acids (LMWOAs). LMWOAs are involved in the nutrients availability and uptake by plants, nutrients detoxification, minerals weathering and microbial proliferation in the soil. At nutrients deficiency conditions citric and oxalic acids are released by plants root in large quantities and increase nutrient solubility like P, Zn, Fe, Mn and Cu in the rhizosphere. These components are the large portion of the carbon source in the soil after exudations are mineralized by microorganisms, quickly. In addition, soil surface sorption can affect their half-life and other behaviors in the soil. In order to study the effect of oxalic and citric organic acids on the extraction of phosphorus and zinc from a calcareous soil, an experiment was conducted.
Materials and Methods: Studied soil was calcareous and had P and Zn deficiency. Soil sample was collected from A horizon (0-30 cm) of Damavand region. 3 g of dried soil sample was extracted with 30 ml of oxalic and citric acids extraction solutions at different concentrations (0.1, 1 and 10 mM) and different time periods (10, 60, 180 and 360 minutes) on an orbital shaker at 200 rev min-1.The soil extracts then centrifuged for 10 minutes (16000g). After filtering, the pH of the extractions was recorded and then phosphorus, calcium and zinc amounts were determined. Soil extraction with distilled water was used as control. Each treatment was performed in 3 replications. Statistical analysis was performed with ANOVA test followed by the Bonferroni method significant level adjustments due to multiple comparisons.
Results and Discussion: The results of variance analysis showed that the effect of different concentrations of organic acids at various times on the pH of extractions was significant at 1% level. Low concentrations of organic acids at various times had no effect on the pH of soil extractions compared to control, but organic acids at 10 mM concentration increased the pH of extractions. This high pH amount was related to the organic acid mineralization and consumption of H+ by microorganisms in the soil. The results of variance analysis also showed that the effect of different concentrations of organic acids at various times in the extraction of Ca from the soil was significant at 1% level .Citric acid extracted higher Ca from the soil compared to oxalic acid. The maximum extracted Ca was observed at 10 mM concentration of citric acid at 10 minutes of shaking time. Extracted Ca at 0.1 and 1 mM concentrations of both organic acids was almost the same at all the times. The higher extraction of Ca with citric acid was due to the Ca precipitation as oxalate. The analysis of variance for P showed that the effect of different concentrations of organic acids at various times was significant at the 1% level. Extracted P by oxalic acid was more than citric acid .The highest amount of P was obtained by 10 mM concentration of oxalic acid at 360 minutes. The amounts of extracted P by both organic acids at 0.1 and 1 mM concentrations were similar to control. Citric acid at 10 mM concentration also released lower P compared to other concentrations and control. More P extraction of oxalate than citrate was due to the Ca-oxalate formation and P release from calcium phosphate in calcareous soil. Different concentrations of organic acids at different time periods had no effect on Zn extraction from the soil and the amount of extracted Zn by organic acids was lower than control.
Conclusion: Organic acids at 10 mM concentration were effective in Ca and P extraction from the soil but had no significant effect on the Zn extraction. It seems that organic acid more than 10 mM concentrations is required for Zn extractionfrom from the calcareous soils. The type and concentration of Organic acids, soil type, shaking time and experimental conditions are important factors that affect the obtained results.
T. Raiesi; A. Hosseinpur; F. Raiesi
Abstract
Introduction: The biological and chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plant roots or by the activity of rhizosphere microflora (16). Municipal sewage ...
Read More
Introduction: The biological and chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plant roots or by the activity of rhizosphere microflora (16). Municipal sewage sludge (MSS) applied to agricultural soils is a well known reusable source of phosphorus (P), nitrogen (N) and other macro- and micro-nutrients (33). Sludge provides a short-term input of plant-available nutrients and stimulation of microbial activity, and it contributes to long term maintenance of nutrient and organic matter pools (33). Availability of P following application of MSS can be influenced by microbial and chemical properties of the soil, MSS composition, and rhizosphere processes. The specific interrelationships between these components have proven to be complex and, despite continued study, a thorough understanding of the interactions among plant roots, manure P, and P solubility has yet to be achieved (42). Little quantitative information is available about the chemical and biological properties in the rhizosphere of bean plant growing in soils un-amended and amended with MSS. Therefore, the objectives of this research were to evaluate the rhizospheric effects of bean on chemical and biological properties in 10 calcareous soils as amended with municipal sewage sludge (MSS) or unamended (control) under rhizobox conditions.
Materials and Methods: Ten surface soil samples (0–30 cm) were collected from Chaharmahal-Va-Bakhtiari province, in the central Iran. Municipal sewage sludge was used from the refinery of Shahrekord city, central Iran. Air dried and sieved (
H. R. Boostani; abdolmajid ronaghi
Abstract
Sewage sludge (SS) as a source of required plant nutrients has been utilized in many countries for crops production. for investigation of SS application affect in compared to chemical fertilizer treatment (F), on dry matter yield (DMY) and concentration of some macro and micro nutrient in corn, a greenhouse ...
Read More
Sewage sludge (SS) as a source of required plant nutrients has been utilized in many countries for crops production. for investigation of SS application affect in compared to chemical fertilizer treatment (F), on dry matter yield (DMY) and concentration of some macro and micro nutrient in corn, a greenhouse experiment (5 × 3 factorial) arranged in a completely randomized design with three replicates was conducted. The first factor included SS levels (0, 10, 20, 40 and 80 gr kg-1 soil) and the second factor was soil textural classes (clay loam, sandy loam and sandy). A chemical fertilizer treatment was also used to compare its affect with that of SS application levels on growth and chemical composition of corn. For comparison of applied SS levels (one factor) with chemical fertilizer treatment in each soil textural classes was used from a completely randomized design with six treatment and three replicates. The results indicated that addition of SS significantly increased DMY of corn in all textures. Application of SS significantly increased N, P, Fe, Zn, Cu and Mn concentration in corn aerial parts and nutrients deficiencies symptoms disappeared. Nutrients concentrations in corn plants did not reach to toxic levels even at high rates of SS application and concentration of Cd and Pb were negligible and not detectable in shoot corn. Based on nutrient deficiency in calcareous soils especially Zn and Fe, application of SS for contrasting with shortage of these elements can be effective way to eliminate these nutrients shortage. In general, application of SS was superior to chemical fertilizer treatment in increasing concentration of nutrients and DMY of corn. Prior to any SS recommendations the results of this experiment needs to be verified under field conditions.
