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 ...
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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.
mehdi nourzadeh haddad; Akbar hasani; mehdi karami mighadam
Abstract
Introduction: Water shortage in arid and semiarid regions is the most serious factor in limiting agricultural activities as it leads to the rapid reduction of yields from both a quantitative and qualitative perspective. Under conditions of water scarcity, leaf temperature rises, which causes plant wilting ...
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Introduction: Water shortage in arid and semiarid regions is the most serious factor in limiting agricultural activities as it leads to the rapid reduction of yields from both a quantitative and qualitative perspective. Under conditions of water scarcity, leaf temperature rises, which causes plant wilting and premature senescence of leaves and, eventually, severes reduction of dry matter production. Use of high-efficient irrigation practices, improvement of soil's physical properties, and use of soil amendments such as superabsorbent polymers are some ways of compensating for water shortage, especially during the growing season. Some materials such as plant residues, manure, various types of compost, and superabsorbent polymeric hydrogels can store various amounts of water and thus increase water retention and storage capacity of soils. Superabsorbent hydrogels, which are also called superabsorbent polymers (SAPs) or hydrophilic polymeric gels, are hydrogels that can absorb substantial quantities of water. Hydrogels are a class of polymeric materials having network structures (with physical or chemical crosslinks) that are very capable of swelling and absorbing large amounts of water. These materials are formed from water-solublepolymers by crosslinking them either using radiation or a crosslinker. Superabsorbents are widely used in many products such as disposable diapers, feminine napkins, soils for agricultural and horticultural purposes, gel actuators, water blocking tapes, medicine for the drug delivery systems and absorbent pads where water absorbency or water retention is important. Water is a major constraint for crop growth in arid and semi-arid regions, as the precipitation is low and uncertain in these areas. Efficient utilization of meager soil and water resources necessitates the adaptation of appropriate water management techniques. Suitable soil moisture increases the biological activities as result of physical and chemical condition of soil improving the crop production finally.
Material and Methods: This experiment was conducted under greenhouse conditions in Shushtar city at northern Khuzestan Province using the randomized complete block design using 13 treatments and with 3 replications. Soil samples were taken from a field in the study area, air dried, and passed through a 2 mm sieve. Seven concentration (0, 0.25, 0.5, 0.75, 1.0, 1.25, and 1.5 percentage) of superabsorbent polymers (Aquasorb and Accepta) were used in greenhouse condition. Superabsorbent and 10 Kg soil thoroughly mixed in each pot. All treatments were irrigated when the plants at control showed sign of wilting. There were three replications of each treatment. NPK fertilizers were applied as urea, diammonium phosphate (DAP) and potassium sulphate (K2SO4) based the soil test. Soil samples were again collected which were analyzed for nitrate-N, total organic carbon (TOC), phosphorus and potassium, bulk density, particle density and saturation percentage.NPK of plant samples were also determined. Data were statistically analysed by Duncan test using SPSS.
Results and Discussion: Results had shown that the highest bulk density (1.515 gr/cm3) seen in control treatment and with increasing the polymer, bulk density decreased significantly to 0.91 gr/cm3 in treatment No.2. Also the treatments No. 4 and 11 shown decreasing EC significantly from 0.9 in control treatment to 0.68 in No.4. Adding superabsorbent had significant effect on Potassium amount of soil. Using superabsorbent had no significant effect on real density, pH, N amount, Phosphorous, soil organic carbon after yield harvesting in soil and amount of Phosphorous in plant. Significant increasing in number of leaves, branches, fresh weight of plant, and fruit weight with using superabsorbent polymers and the highest used polymer level (treatments No. 7 and 13) had the highest effect on fresh weight of plant which reported 47.2 g for No.7 and 90.47 g for No.13. Also using 1 percentage of Accepta superabsorbent (No.12) caused the significant increasing of fruit weight (502.9 g) instead of control (73.5 g). Based on the presented results No. 2 and 9 had the most effects on N of plants, which the N amount in control was 1.31 percentage and in No.2 and 9 were 2.88 and 2.82 measured respectively. Treatments No. 7, 8, 9, and 11 had the most measured plant potassium. Final results had shown the number of bacteria and fungi increased significantly using superabsorbent and the number of bacteria increased to 215 × 104 in No.13 and the number of fungi to 176500 in each gram of soil.
Conclusion: The overall results of this research had shown the promotion of physical, biological, and finally increase the yield as results of using superabsorbent especially Accepta type. Using these superabsorbent polymers in farms need more studies because of more effective climate parameters.