Search

Iron (Fe) is an essential micronutrient for plants and its deficiency occurs in calcareous soils. However, a suitable extractant for the estimation of plant-available Fe and its critical level in calcareous soils depends on the type of soil and plant. The objective of the present study was to evaluate several chemical extractants to estimate available Fe and its critical level for corn growing in calcareous soils from Chaharmahal-Va-Bakhtiari Province. The amount of available Fe was measured by DTPA-TEA, AB-DTPA, 0.01 M calcium chloride, Mehlich IІ, and Mehlich ІІI extractants. At the end of the experiment, corn was harvested, and dry weight, Fe concentration in the plant, and the amount of Fe uptake by corn were determined. Extracted Fe had a significant correlation with all extractants used with maize indices. . The highest correlation coefficients were determined between the DTPA-TEA (0.32-0.94) and AB-DTPA (0.43–0.96) methods and the plant indices. The results of this research showed that the DTPA-TEA and AB-DTPA methods were the most suitable extractants for predicting available Fe content in these soils and the critical level of Fe extracted by these extractants was 2.81 and 3.67 mg kg-1.

With the development of industrial and agricultural production, the cadmium (Cd) pollution in farmland soil is increasing which threatens the quality and safety of agricultural products in China. The purpose of this research is to explore the potential of chelated iron amendments for reducing the bioavailability of Cd to maize plants. The experiment of maize cultivation was carried out in pots. Maize was cultivated in brown soil collected from a northeast region in China and then artificially contaminated with Cd with an average concentration of 10 mg/kg. The potential of ethylenediamine tetra acetic acid ferric-sodium (EDTANa2Fe) and ethylenediamine-N, N'-bis(2-hydroxyphenylacetic acid) ferric-sodium (EDDHAFe) as amendments for Cd immobilization in soils were tested. Effects of different concentrations (0.013, 0.026, 0.053, and 0.08 g/kg) of EDTANa2Fe and EDDHAFe (calculated by iron) on the growth of maize and the Cd and Fe uptake in maize were evaluated. Principle component analysis (PCA) was performed to further analyze the overall effects of iron amendments on Cd accumulation in plants. The results showed that EDTANa2Fe and EDDHAFe at dose of 53 mg/kg reduced available Cd in soil to the value of 5.19 and 4.59 mg/kg, respectively. EDTANa2Fe of 80 mg/kg and EDDHAFe of 26, 53, and 80 mg/kg increased Fe concentration in grains by 34.86%, 36.88%, 41.46%, and 44.05%, respectively, while reduced the Cd content in grains by 39.82%, 42.67%, 48.41%, and 35.08%, respectively. Fe concentration in grains showed a significant negative correlation with the concentration of Cd (P < 0.05). EDTANa2Fe of 53 mg/kg treatment increased the maize yield by 30.45% which was higher than in all other treatments. EDDHAFe treatments of 26 and 53 mg/kg increased the total root length by 39.72% and 48.68%, respectively, and increased the total root surface area by 19.95% and 22.98%, respectively. In general, the application of EDTANa2Fe and EDDHAFe at dose of 53 mg/kg can effectively immobilize Cd in soil and reduce Cd accumulation in maize and improve Fe uptake in grains. [ABSTRACT FROM AUTHOR]

Iron (Fe) is an essential micronutrient for plants and its deficiency occurs in calcareous soils. However, a suitable extractant for the estimation of plant-available Fe and its critical level in calcareous soils depends on the type of soil and plant. The objective of the present study was to evaluate several chemical extractants to estimate available Fe and its critical level for corn growing in calcareous soils from Chaharmahal-Va-Bakhtiari Province. The amount of available Fe was measured by DTPA-TEA, AB-DTPA, 0.01 M calcium chloride, Mehlich IІ, and Mehlich ІІI extractants. At the end of the experiment, corn was harvested, and dry weight, Fe concentration in the plant, and the amount of Fe uptake by corn were determined. Extracted Fe had a significant correlation with all extractants used with maize indices. . The highest correlation coefficients were determined between the DTPA-TEA (0.32-0.94) and AB-DTPA (0.43–0.96) methods and the plant indices. The results of this research showed that the DTPA-TEA and AB-DTPA methods were the most suitable extractants for predicting available Fe content in these soils and the critical level of Fe extracted by these extractants was 2.81 and 3.67 mg kg-1. [ABSTRACT FROM AUTHOR]

In this research available iron was measured in 21 calcareous surface soil samples (0-30 cm) by five methods including DTPA, AB-DTPA, AC-EDTA, hydroxylamine, reference ammonium oxalate and rapid ammonium oxalate. Fe fractions were also determined by the modified sequential extraction procedures introduced by Singh et al. According to results, rapid ammonium oxalate and AC-EDTA methods extracted the maximum (856.03 mg.kg-1) and minimum (4.46 mg.kg-1) amounts of Fe, respectively. Rapid ammonium oxalate extraction method, in addition to Fe-Afeox, extracted other fractions of iron such as Fe-Ex, Fe-Om, Fe-CFeox and Fe-Res. Hydroxylamine method compared to other methods, ectracted Fe mostly from the amorphous oxides source. Regression analysis indicates that Fe-Ex, Fe-AFeox and Fe-Res fractions have major and Fe-Car and Fe-Mnox have minor role in releasing available Fe (with AB-DTPA and DTPA) in the studied soil. According to the statistical relationships, carbonates associated Fe, does not seem a potential source of available Fe in calcareous soils. Organic carbon content and cation exchange capacity of the soils appear the two most influential soil properties that predict available Fe in the studied soils.

Because of low content of available iron (Fe) in soils and its poor mobility in plants, iron fertilization is necessary. Different forms of iron (mineral salts, chelates, nanomaterials) and fertilization strategies (soil and foliar application of solid or liquid fertilizers) are used. The effect of solid mineral fertilizers (A: a mixture of ammonium nitrate and dolomite; B: a mixture of ammonium nitrate and sulfate) enriched with iron sulfate was assessed during a three-year pot experiment. Iron addition did not change the yield of spring rape (first year) or maize (second and third year) significantly, and the effect on iron content in the plants was ambiguous. Fertilizer B with iron had the greatest yield-forming effect, increasing the yield of aboveground parts by 355–874%, and of roots by 211–692% in particular years. All fertilizers (especially containing sulfur) acidified the soil. After the experiment, pH of the soil fertilized with sulfur was 4.1, and of the unfertilized soil – 5.2. Iron addition increased the content of mobile and exchangeable iron in the soil by 12–110% and 2–58%, respectively, but not the content of the fraction bound to MnOx. Combination of sulfur and iron fertilization has a potential to improve soil abundance and plant yield. [ABSTRACT FROM AUTHOR]

• Soil nutrients were evaluated for contribution to grain Zn in different regions. • Soil Fe inhibited Zn accumulation in wheat grain in single wheat region. • High P and low Zn in soil inhibited Zn increase in wheat grain of wheat-maize region. • Soil Amon-N was a dominant factor for grain Zn in rice-wheat region. • Integrated soil nutrient management is needed for grain Zn improvement regionally. It is useful to understand soil nutrients responsible for grain zinc (Zn) variation of winter wheat (Triticum aestivum L.) in different cropping regions, in order to adopt appropriate soil management measures to improve grain Zn nutrition and alleviate human Zn malnutrition. A total of 599 wheat plant and corresponding soil samples were collected from farmers' fields in three typical wheat cropping regions of China in 2015 and 2016, to determine the dominant soil nutrients related to high grain Zn concentration. Obtained results showed that a large variation in grain Zn existed within different regions, with 8%, 9% and 16% of grain samples reaching the recommended level of 40 mg kg−1 in the single wheat, wheat-maize and rice-wheat regions, respectively. In the single wheat region, grain Zn was positively correlated with soil available potassium (K) and Zn, and negatively correlated with available iron (Fe) (P < 0.001), with the available K being 164 and 117 mg kg−1, Zn 0.64 and 0.46 mg kg−1, and Fe 3.3 and 5.2 mg kg−1 for the high and low Zn groups, respectively. In the wheat-maize region, grain Zn was positively correlated with soil available Zn, while negatively correlated with available phosphorus (P) (P < 0.001), with the available Zn being 1.7 and 1.3 mg kg−1, and P 24 and 25 mg kg−1 for the high and low Zn groups, respectively. In the rice-wheat region, grain Zn was positively correlated with soil ammonium nitrogen (Amon-N) and available Zn (P < 0.001), with Amon-N being 7.2 and 4.6 mg kg−1, and available Zn 1.9 and 1.2 mg kg−1 for the high and low Zn groups, respectively. Therefore, it is possible to produce wheat with grain Zn higher than 40 mg kg−1 in farmers' fields, and apart from available Zn, soil available K and Fe in the single wheat region, available P in the wheat-maize region, and Amon-N in the rice-wheat region should also be considered for the purpose of grain Zn improvement. [ABSTRACT FROM AUTHOR]

This paper presents a study of the profile distribution of available micronutrients Fe, Mn, Cu and Zn and radionuclide 137Cs in cultivated soil at the experimental field "Radmilovac" (property of Agricultural Faculty, Belgrade University) in the vicinity of Vinĉa Institute of Nuclear Sciences. The soil belongs to the anthrosol class of anthropogenic soils according to FAO (2006). At first, the deep plowing was performed while preparing soil for planting peach trees followed by cultivation of soil for 12 years. All agricultural treatments at the experimental field ceased for three years. After that period, soil sampling was carried out. Contents of DTPA-extracted Fe, Mn, Cu and Zn were in the range of (mg kg-1): 5.8-41.6; 9.2-34.2; 1-7.6 and 0.2-1.3, respectively. Detected activity concentration (Bq kg-1) for 137Cs ranged from 1.8 to 35. It was noticed that distribution patterns of 137Cs radionuclide and available Cu and Zn along soil depth were very similar and they were analyzed by simple linear regression; mutual affinity for the soil organic matter might affect their distribution in soil. Contents of available Fe and Mn exhibited different, more constant distribution within a soil horizon.

Copyright of Mediterranean Agricultural Sciences is the property of Akdeniz Universitesi Ziraat Fakultesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this research available iron was measured in 21 calcareous surface soil samples (0-30 cm) by five methods including DTPA, AB-DTPA, AC-EDTA, hydroxylamine, reference ammonium oxalate and rapid ammonium oxalate. Fe fractions were also determined by the modified sequential extraction procedures introduced by Singh et al. According to results, rapid ammonium oxalate and AC-EDTA methods extracted the maximum (856.03 mg.kg-1 ) and minimum (4.46 mg.kg-1 ) amounts of Fe, respectively. Rapid ammonium oxalate extraction method, in addition to Fe-Afeox, extracted other fractions of iron such as Fe-Ex, Fe-Om, Fe-CFeox and Fe-Res. Hydroxylamine method compared to other methods, ectracted Fe mostly from the amorphous oxides source. Regression analysis indicates that Fe-Ex, Fe-AFeox and Fe-Res fractions have major and Fe-Car and Fe-Mnox have minor role in releasing available Fe (with AB-DTPA and DTPA) in the studied soil. According to the statistical relationships, carbonates associated Fe, does not seem a potential source of available Fe in calcareous soils. Organic carbon content and cation exchange capacity of the soils appear the two most influential soil properties that predict available Fe in the studied soils. [ABSTRACT FROM AUTHOR]

This study examined the effects of exogenous nitric oxide (NO) on physiological characteristics of peanut (Arachis hypogaea L.) growing on calcareous soil. Sodium nitroprusside (SNP), a NO donor, was root application (directly; slow-release bag; slow-release capsule; slow-release particle) and foliar application. The results showed that SNP application alleviated iron (Fe) deficiency-induced chlorosis, increased the yield of peanut and increased the Fe concentration in peanut grain. SNP, especially supplied by slow-release particle improved the available Fe in soil by reducing pH of soil and increasing available Fe of soil. Furthermore, SNP application significantly increased the H+-ATPase and Fe3+ reductase activities and increased the total Fe concentration in the leaves. Meanwhile, SNP application, especially foliar application enhanced the availability of Fe in the plant by significantly increasing the active Fe content and chlorophyll content in the leaves. In addition, SNP also increased the antioxidant activities, but decreased the superoxide anion (O2•−) generation rate and malondialdehyde content, which protected peanut against the Fe deficiency-induced oxidative stress. Therefore, these results support a physiological action of SNP on the availability, uptake and transport of Fe in the plant and foliar application SNP had the best effects in leaves and SNP supplied by slow-release particle had the best effects in roots. In addition, on the whole, the effects of SNP supplied by slow-release ways were better than directly supplied into the soil. [ABSTRACT FROM AUTHOR]