Pattern of iron distribution in the soil‐plant system and its possible relation to iron‐chlorosis

Abstract

The frequent concentration‐ranges of various nutrient elements in soils and in plants are compared. Iron is different from almost all other nutrient elements in the fact that its optimal concentration range in plants is much lower than its frequent concentration range in soils. It is suggested that this observation is related to a chemical‐physiological mechanism of control on the uptake of iron by plants which in turn may explain the situations in which iron deficiency conditions in plants arise.     

褐煤腐殖酸对不同土壤上小麦生长的影响

Humic acid(HA),a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems,enhances plant growth by chelating unavailable nutrients and buffering pH.We examined the effect of HA derived from lignite on growth and macronutrient uptake of wheat(Triticum aestivum L.) grown in earthen pots under greenhouse conditions.The soils used in the pot experiment were a calcareous Haplustalf and a non-calcareous Haplustalf collected from Raisalpur and Guliana,respectively,in Punjab Province,Pakistan.The experiment consisted of four treatments with HA levels of 0(control without HA),30,60,and 90 mg kg -1 soil designated as HA 0,HA 1,HA 2,and HA 3,respectively.In the treatment without HA(HA 0),nitrogen(N),phosphorus(P),and potassium(K) were applied at 200,100,and 125 mg kg -1 soil,respectively.Significant differences among HA levels were recorded for wheat growth(plant height and shoot weight) and N uptake.On an average of both soils,the largest increases in plant height and shoot fresh and dry weights were found with HA 2(60 mg kg -1 soil),being 10%,25%,and 18%,respectively,as compared to the control without HA(HA 0).Both soils responded positively towards HA application.The wheat growth and N uptake in the non-calcareous soil were higher than those of the calcareous soil.The HA application significantly improved K concentration of the non-calcareous soil and P and NO 3-N of the calcareous soil.The highest rate of HA(90 mg kg -1 soil) had a negative effect on growth and nutrient uptake of wheat as well as nutrient accumulation in soil,whereas the medium dose of HA(60 mg kg -1 soil) was more efficient in promoting wheat growth.     

Influence of Plant Phosphorus and Iron Concentrations on Growth of Soybean

Growth responses to phosphorus (P) and iron (Fe) are commonly assessed based on element concentrations to which plants are exposed. Such data offer little insight about responses to the concentration of P and Fe actually accumulated in plants. In this study, soybean (Glycine max Merr., cv. ‘Biloxi’) was grown on nutrient solutions to induce varying P and Fe concentrations in plant tissues. Leaf P and Fe concentrations were correlated at lower concentrations. However, under high P treatments there was an apparent excess of accumulated P based on plant response. These results were interpreted to indicate that these plants could accumulate P in excess of the amount required for normal physiological activity. There appeared to be no excess accumulation of Fe so that correlations between leaf Fe concentration and leaf area and plant mass were significant for all data. Root mass did not correlate significantly with either leaf P or Fe concentration.     

Effect of commercial amino acids on iron nutrition of tomato plants grown under lime‐induced iron deficiency

The objective of this work was to study the effect of root and foliar application of two commercial products containing amino acids from plant and animal origin on iron (Fe) nutrition of tomato seedlings cultivated in two nutrient media: lime and normal nutrient solutions. In the foliar‐application experiment, each product was sprayed with 0.5 and 0.7 mL L^–1 2, 7, 12, and 17 d after transplanting. In the root application experiment, 0.1 and 0.2 mL L^–1 of amino acids products were added to the nutrient solutions. In both experiments, untreated control plants were included as well. Foliar and root application of the product containing amino acids from animal origin caused severe plant‐growth depression and nonpositive effects on Fe nutrition were found. In contrast, the application of the product from plant origin stimulated plant growth. Furthermore, significantly enhanced root and leaf Fe^III‐chelate reductase activity, chlorophyll concentration, leaf Fe concentration, and Fe^II : Fe ratio were found in tomato seedlings treated with the product from plant origin, especially when the amino acids were directly applied to the roots. These effects were more evident in plants developed under lime‐induced Fe deficiency. The positive results on Fe uptake may be related to the action of glutamic acid, the most abundant amino acid in the formulation of the product from plant origin.     

Comparative study on the effectiveness of several iron compounds in the iron chlorosis correction in citrus plants

A comparative study was carried out on the effectiveness of several commercial Fe‐compounds applied through the soil as well as via leaf spray, with a view to control the Fe‐chlorosis in Verna lemon trees directly grafted on sour orange rootstock, with a Salustiano orange tree as intermediate. The results obtained during 1985 confirm the conclusions of previous experiments: The most effective treatments were the leaf spray with Fe‐polyflavonoids, though it is interesting that Fe‐chelates applied to soil were also highly effective, as Fe leaf levels were higher than 100 ppm one month after treatments.     

Micronutrient availability in soils of Northwest Bosnia and Herzegovina in relation to silage maize production

Maize (Zea mays L.) is the most widely grown crop in Bosnia and Herzegovina especially in Northwest part of the country. Considering that, the maize is extremely sensitive to micronutrient deficiency the main aim of this study was to asses: (1) micronutrient availability in soil, (2) micronutrient status in silage maize; and (3) the relationship between micronutrient soil availability and maize plant concentration. Soil samples for micronutrient availability (n?=?112) were collected from 28 farms in 7 municipalities. Plant available micro- and macro- nutrients in soil were extracted using Mehlich-3, except plant available Se was extracted using 0.1M KH₂PO₄. Result showed that on average there was no significant difference between different soil types regarding their potential in plant available nutrients. P deficiency was present both, in soil and plants in whole region. Soil extractable P was ranging from 0.003–0.13?g?kg^?1 and total plant P was ranging from 0.79–4.95?g?kg^?1. Zinc deficiency was observed in two locations both in soil (0.71?mg?kg^?1; 0.79?mg?kg^?1) and plant (11.5?mg?kg^?1; 15.8?mg?kg^?1). Potential Se soil deficiency was observed on some locations, while Se plant status is not high enough to meet daily requirements of farm animals. Extractable soil nutrients could be used as relatively good predictor of potential soil and plant deficiencies, but soil nutrient interactions and climate conditions are highly effecting the plant uptake potential.     

Interaction of Different Iron Chelates with an Alkaline and Calcareous Soil: A Complementary Methodology to Evaluate the Performance of Iron Compounds in the Correction of Iron Chlorosis

Abstract

A great number of studies have shown that the stability of iron chelates as a function of pH is not the unique parameter that must be considered in order to evaluate the potential effectiveness of Fe‐chelates to correct iron chlorosis in plants cultivated in alkaline and calcareous soils. In fact, other factors, such as soil sorption on soil components or the competition among Fe and other metallic cations for the chelating agent in soil solution, have a considerable influence on the capacity of iron chelates to maintain iron in soil solution available to plants. In this context, the aim of this work is to study the variation in concentration of the main iron chelates employed by farmers under field conditions—Fe‐EDDHA (HA), Fe‐EDDHMA (MA), Fe‐EDDHSA (SA), Fe‐EDDCHA (CA), Fe‐EDTA (EDTA), and Fe‐DTPA (DTPA)—in the soil solution of a calcareous soil over time. To this end, soil incubations were carried out using a soil:Fe solution ratio corresponding to soil field capacity, at a temperature of 23°C. The soil used in the experiments was a calcareous soil with a very low organic matter content. The variation in concentration of Fe and Fe‐chelates in soil solution over time were obtained by measuring the evolution in soil solution of both the concentration of total Fe (measured by AAS), and the concentration of the ortho‐ortho isomers for Fe‐EDDHA and analogs or chelated Fe for Fe‐EDTA and Fe‐DTPA (measured by HPLC). The following chelate samples were used: a HA standard prepared in the laboratory and samples of HA, MA, SA, CA, Fe‐EDTA, and Fe‐DTPA obtained from commercial formulations present in the market. The percentage of iron chelated as ortho‐ortho isomers for HAs was: HA standard (100%); HA (51.78%); MA (60.06%); SA (22.50%); and CA (27.28%). In the case of Fe‐EDTA and Fe‐DTPA the percentages of chelated iron were 96.09 and 99.12, respectively. Results show that it is possible to classify the potential effectiveness of the different types of iron chelates used in our experiments as a function of two practical approaches: (i) considering the variation of total iron in soil solution over time, MA is the best performing product, followed by HA, CA, SA, DTPA, EDTA, and ferrous sulfate in the order listed and (ii) considering the capacity of the different iron chelates to maintain the fraction of chelated iron (ortho‐ortho isomers for HA, MA, SA, and CA and total chelated iron for EDTA and DTPA) in soil solution, the order is: SA > CA > HA > MA > EDTA ≈ DTPA. This result, that is related to the nature of the chelate and does not depend on the degree of chelated Fe in the products, indicates that SA and CA might be very efficient products to correct iron chlorosis. Finally, our results also indicate the suitability of this soil incubation methodology to evaluate the potential efficiency of iron compounds to correct iron chlorosis.     

Co-situs application of controlled-release fertilizers to alleviate iron chlorosis of paddy rice grown in calcareous soil

Abstract

Co-situs is the placement with one application of a sufficient amount of controlled-release fertilizer for an entire growing season at any site, together with seeds or seedlings, without causing fertilizer salt injury. An experiment was conducted to find an efficient method for ameliorating Fe deficiency in two rice cultivars (cv. Tsukinohikari and cv. Sasanishiki) grown in a calcareous soil (pH 9.2, CaCO₃ 384 g kg^?1), which was poor in organic matter (0.1 g kg^?1) and available Fe (3.0 μg g^?1 soil). The field treatments consisted of co-situs application of the following fertilizers: 1) controlled-release NPK fertilizer (CRF-NPK) containing no micronutrients; 2) controlled-release NPK fertilizer containing micronutrients (CRF-M1); and 3) controlled-release NPK fertilizer containing micronutrients (CRF-M2). The main difference between CRF-M1 and CRF-M2 was that the former had larger granules than the latter. All the fertilizers were placed in contact with the roots of rice seedlings at transplanting time. Plants in the CRF-M1 and CRF-M2 treatments had similar lengths, number of stems, leaf age, and leaf color (SPAR value) during the cultivation period. By contrast, plants from the CRF-NPK treatments grew poorly, showed severe chlorosis symptoms of Fe deficiency, and all died on 30 DAT. Plants of both cultivars accumulated more macroand micronutrients with the CRF-M2 treatment than with the CRF-M1 treatment. The grain yield of cv. Tsukinohikari was 0.0, 1,910, and 2,160 kg ha^?1 for the CRF-NPK, CRF-M1, and CRF-M2 treatments, respectively, and 0.0, 2,490, and 2,860 kg ha^?1 for the same treatments for cv. Nihonbare. Chlorosis due to iron deficiency was successfully ameliorated and world-average grain yields were obtained with the co-sites application of both controlled-release fertilizers.     

Strawberry recovers from iron chlorosis after foliar application of a grass‐clipping extract

Bare‐root transplants of strawberry (Fragaria × ananassa Duch. cv. Selva) were transferred to nutrient solutions with or without iron. After 35 d of growth, plants in the solution without iron became chlorotic and had morphological changes in roots typical of iron‐deficiency chlorosis (IDC). Acidification of the nutrient solution was also observed. We tested a grass‐clipping extract to correct IDC in strawberry plants by foliar application to some chlorotic plants. We also assessed the effects of this product on plant growth, Fe allocation, as well as morphological and physiological parameters related with IDC. After the second spray, leaf chlorophyll increased in the youngest expanded leaves. The total content of iron in plants increased from 1.93 mg to 2.37 mg per plant after three sprays, accounting for 80% of the total iron supplied by the extract. Newly formed roots from sprayed plants had a normal morphology (no subapical swollen zone) but a higher ferric chelate–reductase (FC‐R; EC 1.16.1.17) activity per root apex compared with roots from plants grown with iron or untreated chlorotic plants. Acidification of the nutrient solution continued in sprayed recovered plants. The results suggest an uncoupling of the regulation of morphological and physiological mechanisms related to IDC: FC‐R activity seems to be controlled by roots on their own or together with shoots, while morphological changes in roots are apparently regulated only by the level of iron in shoots.     

树干高压注射铁肥矫正苹果失绿症及其机理

利用N-Fe、邻二氮杂菲铁和.59Fe作为铁源,以3-8年生富士／八棱海棠为试材进行主干强力高压注射试验。结果表明,铁肥树干强力高压注射,主要以二价铁(Fe2+)沿中央木质部的导管运输,大部分向下运输,使铁在根中大量贮存;向上运输较少,运输速度为每小时数百厘米,矫正缺铁失绿症的速度比根系输液慢,但由于根中贮存大量的铁,持效期较长。主干强力高压注射产生肥害的机理是先使吸收根中毒,然后导致叶片枯萎,提高注射部位,提高注射液浓度和减少注射的用药量,可以防止或减轻肥害的产生。     

Predicting the incidence of iron chlorosis in calcareous soils of southern Spain

Abstract

Iron chlorosis is a serious crop production problem in many calcareous soils of Southern Spain. The objective of this study was to determine which indigenous soil properties (i.e., those which are essentially permanent) were related to Fe chlorosis. Experiments, using two chickpea (Cicer ariethinum L.) cultivars and a sunflower (Helianthus annuuus L.) cultivar, were carried out in a growth chamber with 25 calcareous soils representing widespread Xerofluvents, Xerorthents, Xerochrepts, Haploxeralfs, Rodoxeralfs, Chromoxererts, and Pelloxererts of Southern Spain. The average chlorophyll contents for the three cultivars were significantly correlated with several properties of the carbonate and Fe oxide phases, such as calcium carbonate equivalent (r = 0.69***), “active lime”; (r = 0.58**), acid NH₄‐oxalate extractable Fe (r = 0.68***), Tiron‐extractable Fe (r = 0.61**), and DTPA‐extractable Fe (r = 0.55**). The present and other studies indicate that the soil property most consistently related to Fe chlorosis is acid NH₄‐oxalate extractable Fe (Feo). The Feo critical level separating soils with a high probability from those with a low probability of responding to Fe fertilization was 0.63 g/kg soil, a value similar to those found in other studies. This further supports the use of Feo as a key property to predicting the appearance of Fe chlorosis.     

不同铁形态对水稻根表铁膜及铁吸收的影响

通过溶液培养试验研究了FeCl2?4H2O和FeCl3?6H2O对水稻根表铁膜数量及铁吸收的影响。结果表明,FeCl2处理时水稻根表铁膜浓度是FeCl3处理的197%～233%。利用EDTA-BPDS对铁膜形态分析看出,根表铁膜中Fe3+占85%～92%,Fe2+占8%～15%。水稻天优998根表铁膜数量显著高于培杂泰丰,其铁吸收是培杂泰丰的115%～138%。两种铁形态处理明显提高水稻的根系活力,其中,FeCl2处理时水稻根系活力增加24%～69%,FeCl3为16%～54%。FeCl2处理时水稻根系SOD、POD和CAT活性分别增加11%～32%、15%～30%和30%～31%,但FeCl3处理没有明显影响。上述结果表明一定浓度铁处理明显增加水稻根表铁浓度和铁吸收;与FeCl3处理相比,FeCl2处理能提高根系抗氧化酶活性,增加水稻的铁吸收和根表铁膜数量。     

Ryegrass yield and nutrient status after biochar application in two Mediterranean soils

This study was conducted to evaluate whether biochar, produced by pyrolysis at 300°C from rice husk and grape pomace (GP), affects plant growth, P uptake and nutrient status. A 3-month period of ryegrass (Lolium perenne L.) cultivation was studied on two Mediterranean agricultural soils. Treatments comprised control soils amended only with compost or biochar, and combinations of biochar plus compost, with the addition of all nutrients but P (FNoP) or without any fertilization at all (NoF). Application of both types of biochar or/with compost, in the presence of inorganic fertilization except P, significantly increased (P < 0.05) dry matter yield of ryegrass (58.9–77.6%), compared with control, in sandy loam soil, although no statistically significant increase was observed in loam soil. GP biochar and GP biochar plus compost amended loam soil harvests gave higher P uptake than control, in the presence of inorganic fertilization except P, whereas in sandy loam soil, a statistical increase was recorded only in the last harvest. In addition, Mn and Fe uptake increased with the addition of the amendments in both soils, while Ca increased only in the alkaline loam soil. Biochar addition could enhance ryegrass yield and P uptake, although inorganic fertilization along with soil condition should receive special attention.     

铁炉渣施加对稻田水养分动态的影响

为了阐明铁炉渣施加对稻田水养分动态的影响,对福州平原稻田不同铁炉渣施加水平下稻田水养分动态进行测定与分析。结果表明:对照、处理一、处理二、处理三样地稻田表层水中磷酸盐含量分别为657.3,622.2,546.8,474.1μg/L;铵氮含量分别为3.9,3.5,3.1,2.4mg/L;硫酸盐含量分别为82.8,69.1,66.0,69.6mg/L;溶解性有机碳含量分别为13.1,14.4,14.2,13.4mg/L。0-10cm土壤水中磷酸盐含量分别为135.4,141.7,161.1,201.4μg/L;铵氮含量分别为3.0,4.8,5.5,5.1mg/L;硫酸盐含量分别为84.6,59.1,81.6,70.6mg/L;溶解性有机碳含量分别为37.6,46.0,44.5,43.6mg/L。10-20cm土壤水中磷酸盐含量分别为68.6,100.3,113.8,141.6μg/L;铵氮含量分别为4.7,4.9,8.7,5.6mg/L;硫酸盐含量分别为81.9,75.1,62.8,60.0mg/L;溶解性有机碳含量分别为55.5,43.8,58.3,48.8mg/L。20-30cm土壤水中磷酸盐含量分别为138.0,156.1,166.6,188.6μg/L;铵氮含量分别为2.3,2.3,4.2,4.7mg/L;硫酸盐含量分别为78.6,61.5,70.2,73.3mg/L;溶解性有机碳含量分别为49.4,42.8,50.1,45.4mg/L。表层水中磷酸盐、铵氮和硫酸盐含量对照样地高于处理样地,0-30cm土壤水中磷酸盐、铵氮对照样地低于处理样地,硫酸盐含量高于处理样地,溶解性有机碳变化特征不明显。     

Association of soil properties and soil and plant iron to iron deficiency response in rice (Oryza Sativa L.)

Abstract

Problems are invariably encountered when attempts are made to explain the variability in Bray percent yields or plant response in terms of soil or plant iron (Fe). To resolve this inconsistency, the present investigation was initiated to identify a combination of soil extractable Fe, soil properties and form of plant Fe that may be used as a measure of Fe deficiency. The study involved 16 diverse soils, using upland rice (Oryza sativa L.) as the test crop and Fe‐EDDHA [ferric ethylenediamine di (o‐hydroxyl‐phenyl acetic acid)] as source of Fe. The results showed that Bray percent yields were neither related to DTPA (diethylenetriamine pentaacetic acid) or EDTA (ethylenediamine tetraacetic acid) extractable Fe nor with total plant Fe. Even the inclusion of pH, lime, organic carbon and clay data in the regression equations was of no value. However, Bray percent yields were significantly and positively (r = 0.57* ) associated with ferrous Fe (Fe²⁺) in 40‐day‐old rice plants. The explanation concerning variability in Bray percent yields obtained on diverse soils could be increased about one and half 2 times (R²= 0.59*) if the contribution of lime and soil pH was also incorporated in the stepwise regression analysis. The individual contribution to R of lime, pi respectively. Thus, it appears that Fe²⁺ concentration in plants (along with soil pH) may identify Fe deficiency. The critical limit to separate Fe deficient from green rice plants was set at 45 ug Fe²⁺/g in the leaves.     

Mineral composition of peach leaves affected by iron chlorosis

The effect of Fe chlorosis on the mineral composition of field grown peach tree leaves was studied in two different areas. No significant differences in total Fe content were found, whereas 2,2’ bipyridyl extractable Fe, K and the K/Ca ratio were significantly affected in both experiments. Phosphorus and the P/Fe ratio were significantly affected only in one experiment.     

Effect of Thiobacillus,sulfur, and phosphorus on the yield and nutrient uptake of canola and the chemical properties of calcareous soils in Iran

This factorial experiment consists of four levels of sulfur+Thiobacillus and three levels of triple superphosphate arranged in a completely randomized block design in three regions. With an increased sulfur+Thiobacillus and phosphorus (P), grain yield, phosphorus, iron (Fe), and zinc (Zn) uptake of canola increased in Qom and Mazandaran. Combined treatments of S₂₀₀₀T₄₀ and P_100% showed these properties most. In Safiabad, S₁₀₀₀T₂₀ resulted in a significant increase of P, Fe, and Zn uptake of canola, and no significant effect was found on the grain yield. The highest Fe and Zn concentrations in Qom soil was measured in S₂₀₀₀T₄₀. In Safiabad, maximum Fe concentration in soil was registered by S₁₀₀₀T₂₀ and P_65%. The minimum soil pH of Qom and Mazandaran was recorded by S₁₀₀₀T₂₀ and S₂₀₀₀T₄₀, respectively. The effect of sulfur and Thiobacillus on nutrients uptake and canola yield was good and indicates its potential for alleviating the impacts of calcareous soils.     

Field-level comparison of nitrogen rates and application methods on maize yield,grain quality and nitrogen use efficiency in a humid environment

Appropriate nitrogen (N) management practices are of critical importance in improving N use efficiency (NUE), maize (Zea mays) yield and environmental quality. A six-year (2005–2010) on-farm trial was conducted in Ottawa, Canada to assess the effects of N rates and application methods on grain yield and NUE. In four out of the six-year study, grain yield increased by 60–77 kg ha^?1 by sidedress, compared to 49–66 kg ha^?1 for each kg N ha^?1 applied at preplant. Grain yield response to N between the two strategies was similar in the other growing seasons. Sidedress strategy required 15 kg N ha^?1 less of the maximum economic rate of N (MERN) than preplant application. Our results indicate that sidedress application of 90–120 kg N ha^?1 with a starter of 30 kg N ha^?1 resulted in greater yield, grain quality and NUE than preplant N application in this cool, humid and short growing-season region.     

Mineral composition of peach leaves affected by iron chlorosis

Abstract

The effect of Fe chlorosis on the mineral composition of field grown peach tree leaves was studied in two different areas. No significant differences in total Fe content were found, whereas 2,2’ bipyridyl extractable Fe, K and the K/Ca ratio were significantly affected in both experiments. Phosphorus and the P/Fe ratio were significantly affected only in one experiment.