جستجوی مقالات مرتبط با کلیدواژه "mineral acids" در نشریات گروه "آب و خاک"

Phosphorus is one of the most important elements required by plants and it has many different roles, including energy production and transfer, increasing rooting, grain production and improving the quantity and quality of agricultural products. Unfortunately, more than 70% of the phosphorus entering the soil through phosphate fertilizers is stabilized and removed from the accessibility of plants. Therefore, phosphorus stabilization has caused the use of more chemical fertilizers and the amount of total phosphorus in the soil has increased and sometimes the entry of elements along with phosphate fertilizer may cause soil pollution. In order to increase the solubility of insoluble phosphates in the soil or to prevent phosphorus stabilization, environmentally friendly phosphate-solubilizing microorganisms (PSM) such as bacteria, fungi, actinomycetes and algae can be employed. These microorganisms are able to convert insoluble inorganic and organic compounds of phosphorus into soluble compounds by various methods such as production of mineral and organic acids, proton production, and secretion of siderophore, chelation and production of phosphatase enzyme. In mineral soils containing large amounts of calcium, magnesium, iron and aluminum phosphates, the production of mineral and organic acids and in organic soils the phosphatase enzymes are mostly effective. Genes encoding phosphate solubility have been isolated mainly from Erwiniaherbicola, Esherichia coli and Morgonellamorgani. Some of these genes include ushA, agp, cpdB and napA. Despite the existing problems, fortunately, good progress has been made in the field of genetic engineering of phosphate-solubilizing microorganisms so that phosphate-solubilizing genes can be transferred to other bacteria. Due to the fact that soils contain both inorganic and organic compounds, it is recommended to use a microorganism with the ability to dissolve both organic and mineral compounds and a mixture of some microorganisms.

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.

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.

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.

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.