Iron‐manganese interactions among clones of Nilegrass

Tetraploid clones of Nilegrass (Acroceras macrum, Stapf.) develop a chlorosis resembling iron (Fe) deficiency on acid (pH 5.0) soils in the Midlands of KwaZulu, Natal, South Africa. Hexaploid and pentaploid clones appear more resistant to the disorder. Iron deficiency would not be expected in such acid soils, but foliar sprays of Fe sulfate reduce the symptoms within 24 hours. Aluminum (Al) toxiciry has been ruled out as a cause of this chlorosis on the basis of soil tests. Manganese (Mn)‐induced Fe deficiency has been postulated. Six Nilegrass clones, differing in ploidy levels, were grown under low Fe or high Mn levels in nutrient solutions, in Mn‐toxic soil, in calcareous soil and in a standard potting soil at pH 7.0. Differential chlorosis symptoms, similar to those observed in the field, were reproduced in plants grown in low Fe or high Mn solutions, in neutral potting soil and in calcareous soil at pH 7.8. Based on plant symptoms and dry weights, the tetraploids were generally more sensitive to these conditions than hexaploid or pentaploid clones. However, in Mn‐toxic soil, plants had leaf tip necrosis rather than the chlorosis typical of Fe deficiency. When grown in a standard potting soil at pH 7.0, plants showing chlorosis accumulated higher concentrations of phosphorus (P), Al, copper (Cu), Mn, Fe, and zinc (Zn) than non‐chlorotic plants. Differential susceptibility to chlorosis is apparently associated with interference of such elements in Fe metabolism, and not with differential Fe concentrations in plant shoots. Additional studies are needed to determine the chemical states of Fe and Mn in root zones and within plant shoots of these clones. Resolution of the differential chlorosis phenomenon would contribute to fundamental knowledge in mineral nutrition and could be helpful in tailoring plant genotypes to fit problem soils.     

CHLOROSIS IN WILD PLANTS: IS IT A SIGN OF IRON DEFICIENCY?

ABSTRACT

Chlorosis in crops grown on calcareous soil is mainly due to iron (Fe) deficiency and can be alleviated by leaf application of soluble Fe²⁺ or diluted acids. Whether chlorosis in indigenous plants forced to grow on a calcareous soil is also caused by Fe deficiency has, however, not been demonstrated. Veronica officinalis, a widespread calcifuge plant in Central and Northern Europe, was cultivated in two experiments on acid and calcareous soils. As phosphorus (P) deficiency is one of the major causes of the inability of many calcifuges to grow on calcareous soil we added phosphate to half of the soils. Leaves in pots with the unfertilized and the P-fertilized soil, respectively, were either sprayed with FeSO₄ solution or left unsprayed. Total Fe, P, and manganese (Mn) in leaves and roots and N remaining in the soil after the experiment were determined. In a second experiment, no P was added. Leaves were either sprayed with FeSO₄ or with H₂SO₄ of the same pH as the FeSO₄ solution. Degree of chlorosis and Fe content in leaves were determined. Calcareous soil grown plants suffered from chlorosis, which was even more pronounced in the soils supplied with P. Newly produced leaves were green with Fe spray but leaves that were chlorotic before the onset of spraying did not totally recover. H₂SO₄ spray even increased chlorosis. This demonstrated that chlorosis was due to Fe deficiency. As total leaf Fe was similar on acid and calcareous soil, it was a physiological Fe deficiency, caused by leaf tissue immobilization in a form that was not metabolically “active”. Iron in the leaves was also extracted by 1,10-phenanthroline, an Fe chelator. In both experiments, significant differences between leaves from acid and calcareous soil were found in 1,10-phenanthroline extractable Fe but not in total leaf Fe, when calculated on a dry weight basis. Differences in 1,10-phenanthroline extractable Fe were more pronounced when calculated per unit dry weight than calculated per leaf area, whereas the opposite condition was valid for total leaf Fe.     

Depressed growth of non‐chlorotic vine grown in calcareous soil is an iron deficiency symptom prior to leaf chlorosis

The development of iron deficiency symptoms (growth depression and yellowing of the youngest leaves) and the distribution of iron between roots and leaves were investigated in different vine cultivars (Silvaner, Riparia 1G and SO4) grown in calcareous soils. As a control treatment all cultivars were also grown in an acidic soil. Only the cultivars Silvaner and Riparia 1G showed yellowing of the youngest leaves under calcareous soil conditions at the end of the cultivation period. All cultivars including SO4 showed severe shoot growth depression, by 50 % and higher, before yellowing started or without leaf yellowing in the cultivar SO4. Depression of shoot growth occurred independently from that of root growth. In a further treatment the effect of Fe‐EDDHA spraying onto the shoot growth of the cultivar Silvaner after cultivation in calcareous soil was investigated. Prior to Fe application plants were non‐chlorotic, but showed pronounced shoot growth depression. Spraying led to a significant increase in shoot length, though leaf growth was not increased. Accordingly, depression of shoot growth of non‐chlorotic plants under calcareous soil conditions and with ample supply of nutrients and water has been evidenced to be at least partly an iron deficiency symptom. We suggest that plant growth only partially recovered because of dramatic apoplastic leaf Fe inactivation and/ or a high apoplastic pH which may directly impair growth. Since growth was impaired before the youngest leaves showed chlorosis we assume that meristematic growth is more sensitively affected by Fe deficiency than is chlorophyll synthesis and chloroplast development. In spite of high Fe concentrations in roots and leaves of the vines grown in calcareous soils plants suffered from Fe deficiency. The finding of high Fe concentrations also in young, but growth retarded green leaves is a further indication that iron deficiency chlorosis in calcareous soils is caused by primary leaf Fe inactivation. However, in future, only a rigorous study of the dynamic changes of iron and chlorophyll concentration, leaf growth and apoplastic pH at the cellular level during leaf development and yellowing will provide causal insights between leaf iron inactivation, growth depression, and leaf chlorosis.<?show $6#>     

Adaptation of some introduced eragrostis species to calcareous soil and acid mine spoil

Abstract

Plant growth is frequently limited by Fe‐related chlorosis on calcareous soils and by mineral toxicities on strongly acid soils and mine spoils. Better adapted varieties are needed for both soil situations, which are not always economically correctable. In a search for such geraplasm, 4 species (20 accessions) of Eragrostis were grown in greenhouse pots of a calcareous soil at pH 7.3. Two species were also compared on acid mine spoil at pH 3.5 and 4.7.

Species, and accessions within species, differed significantly in tolerance to the calcareous soil, as measured by susceptibility to chlorosis and yield of plant tops. The range in top yield was 11‐fold for accessions of Eragrostis capensis, 3‐fold for Eragrostis lehmanniana, and 1.7‐fold for Eragrostis superba. Eragrostis plana (P.I. 364340) was more tolerant to acid mine spoil (pH 3.5) but less tolerant to calcareous soil (pH 7.3) than Eragrostis superba (P.I. 364833).

Chlorosis and poor growth of certain accessions on calcareous soil (pH 7.3) were not explained by specific mineral deficiencies or toxicities. However, the tops of chlorosis‐susceptible accessions had lower ratios of Fe/Mn, Fe/Zn, and Fe/Cu than those of chlorosis‐resistant accessions. This imbalance is believed to interfere with Fe metabolism in plant tops.

Results suggested that superior strains of Eragrostis species can be selected for adaptation to calcareous or acid soils and that certain accessions characterized in these studies can be useful in studying the physiological mechanisms of mineral stress resistance in plants.     

A greenhouse technique for screening Trifolium seedlings for iron‐deficiency chlorosis 1

Susceptible Trifolium plants often exhibit symptoms of iron (Fe)‐deficiency chlorosis when grown on high pH, calcareous soils. A greenhouse method was developed to screen seedlings for Fe‐deficiency chlorosis. ‘Yuchi’ arrowleaf (T. vesiculosum Savi.) and ‘Dixie’ crimson (I. incarnatum L.) clover seedlings were grown in “Super Cell”; Cone‐tainers in six calcareous Texas soils differing in Fe and selected other chemical characteristics. At the fourth trifoliolate leaf stage, chlorosis was induced by saturating the soil for a minimum of 2 weeks. The soils differed in their capacity to induce chlorosis in both clovers. Yuchi was more susceptible than Dixie, showing a higher percentage of chlorosis in five of the six soils. The results indicate that this screening method would be a useful tool for studying Fe‐deficiency chlorosis in Trifolium spp.     

Soil Properties Influencing Iron Chlorosis in Grapevines Grown in the Montilla‐Moriles Area,Southern Spain

Abstract

Iron (Fe) chlorosis, an Fe deficiency commonly observed in grapevines cultivated on calcareous soils, generally inhibits plant growth and decreases yield. The objective of this research was to relate the incidence of Fe chlorosis in vines of the Montilla‐Moriles area, southern Spain, to indigenous soil properties. Thirty‐five grapevines (V. vinífera L. cv. Pedro Ximenez grafted on V. berlandieri×V. rupestris 110 Ritcher) showing different degree of Fe chlorosis were selected from 13 vineyards. The leaf chlorophyll concentration (estimated by the SPAD value measured with a Minolta meter) was positively correlated with the contents in different soil Fe forms but not with alkalinity‐related soil properties (pH, calcium carbonate equivalent, and active lime). The acid NH₄ oxalate‐extractable Fe (Fe_o) was the most useful simple variable to predict the occurrence of Fe chlorosis. A Fe_o/active lime ratio of 25×10^–4 was found to be useful to class soils into two groups according to the probability of inducing Fe chlorosis.     

小麦与花生间作改善花生铁营养的效应研究

采用砂-土联合培养根箱试验装置,模拟田间试验研究石灰性土壤小麦与花生间作改善花生Fe营养的效应结果表明,石灰性土壤高pH和高CaCO3是导致花生缺Fe黄化的主要原因。叶片已发生黄化的花生与小麦间作可明显改善花生缺Fe症状,间作16d后花生根际土壤有效铁含量、花生新叶叶绿素和活性Fe含量均显著提高。小麦与花生间作对改善花生Fe营养的效应可能与缺Fe小麦根分泌的Fe载体对土壤中Fe活化有关。     

Micronutrient status of crops in selected areas is Egypt

Abstract

Reclamation of sandy and calcareous desert lands in. Egypt for intensive cropping has considerable effect on the fertilizer requirement for most crops. The yield records, together with frequent visual appearances of micronutrient deficiency symptoms on economically important crops were the main reasons for investigating the status of micronutrients in these areas by means of leaf and soil analyses. Sites were selected to represent sandy and calcareous soils in newly reclaimed areas as well as loamy alluvial ones in the Nile‐Valley and Delta. Over 10000 soil and leaf samples were collectes in the last 5 years to evaluate the soil/plant fertility status within the area. The major deficiencies were found to be of Fe Mn and Zn revealed in both soil and plant analyses. Regarding soil type effects, Fe‐deficiency dominated on calcareous soil, Zn‐deficit on the sandy soils and Mn‐deficiency mostly on alluvial soils. Leguminous crops were most sensitive to Fe‐deflciency whereas cereals; especially maize and rice were most sensitive to Zn‐deficiency. It is problem that using Zn, Mn, Fe fertilizer will become a common practice in Egypt for different crops in the near future.

In some west‐Delta calcareous areas, high B was found in both soils and plants. Also, Cu accumulation accurred due to the heavy use of Cu‐fungicides which may eventually become a major pollution problem.     

Screening for resistance to iron deficiency chlorosis in dry bean using iron reduction capacity

Identifying cultivars resistant to iron (Fe) deficiency chlorosis so prevalent in calcareous soils is a more economical solution than fertilizer application in field crops. The current method of screening for resistance using chlorosis ratings in field trials is time consuming and highly variable. Root Fe reduction successfully separated cultivars or rootstocks, varying widely in resistance, of soybean (Glycine max L.), peach (Prunus persica L.), and grape (Vitis spp.), but was unsuccessful in sub‐clover (Trifolium subterraneum L.). Dry bean (Phaseolus vulgaris L.) exhibits Fe deficiency chlorosis in calcareous soils and initiates Fe reduction by the roots in response to such stress. The resistance of 24 dry bean cultivars to Fe deficiency chlorosis was assessed by measuring and summing daily Fe reduction by the roots. The cultivars were grown both hydroponically in an environmental chamber in low Fe solutions (0.05 mg‐L^‐1) and at three field sites in both 1995 and 1996. A significant relationship (P<0.01) between field chlorosis scores made 36 days after planting and root Fe reduction summations was observed for all sites in 1995 and 1996 (r = ‐0.42 to ‐0.71). The variability of chlorosis scores among sites, especially in 1996, points out the difficulty of using field chlorosis scores for screening. These results indicate that measurements of root Fe reduction can be used to predict resistance to Fe deficiency chlorosis in dry bean. Successful implementation of this technique should reduce if not eliminate field trials for screening resistance to Fe deficiency chlorosis.     

Iron fertilizers applied to calcareous soil on the growth of peanut in a pot experiment

A greenhouse pot experiment was conducted with peanuts (Arachis hypogaea L., Fabceae) to evaluate iron compound fertilizers for improving within-plant iron content and correcting chlorosis caused by iron deficiency. Peanuts were planted in containers with calcareous soil fertilized with three different granular iron nitrogen, phosphorus and potassium (NPK) fertilizers (ferrous sulphate (FeSO₄)–NPK, Fe–ethylendiamine di (o-hydroxyphenylacetic) (EDDHA)–NPK and Fe–citrate–NPK). Iron nutrition, plant biomass, seed yield and quality of peanuts were significantly affected by the application of Fe–citrate–NPK and Fe–EDDHA–NPK to the soil. Iron concentrations in tissues were significantly greater for plants grown with Fe–citrate–NPK and Fe–EDDHA–NPK. The active iron concentration in the youngest leaves of peanuts was linearly related to the leaf chlorophyll (via soil and plant analyzer development measurements) recorded 50 and 80 days after planting. However, no significant differences between Fe–citrate–NPK and Fe–EDDHA–NPK were observed. Despite the large amount of total iron bound and dry matter, FeSO₄–NPK was less effective than Fe–citrate–NPK and Fe–EDDHA–NPK to improve iron uptake. The results showed that application of Fe–citrate–NPK was as effective as application of Fe–EDDHA–NPK in remediating leaf iron chlorosis in peanut pot-grown in calcareous soil. The study suggested that Fe–citrate–NPK should be considered as a potential tool for correcting peanut iron deficiency in calcareous soil.     

INHERITANCE OF RESISTANCE TO IRON DEFICIENCY CHLOROSIS IN CHICKPEA (CICER ARIETINUM L.)

Iron (Fe)-deficiency chlorosis causes considerable yield losses in chickpea (Cicer arietinum L.) when susceptible genotypes are grown in calcareous soils with high pH. The most feasible method for alleviating Fe deficiency is the selection of suitable cultivars resistant to Fe deficiency chlorosis. ICC 6119 (desi type), which is Fe-deficient chlorosis, was crossed with CA 2969 and Sierra (kabuli types), resistant to Fe deficiency chlorosis. Inheritance of resistance to Fe deficiency in chickpea revealed that the resistance was controlled by a single dominant gene in these genotypes crossed. A negative selection for resistance to Fe deficiency chlorosis will be effective after segregating generations.     

Phytosiderophore release as a criterion for genotypic evaluation of iron efficiency in oat

Iron (Fe) deficiency in small grains grown on calcareous soils results in reduced yields, is difficult and expensive to treat with fertilizer, and is complicated to overcome by genetic field screening due to heterogeneous soil and environmental conditions. Recently, phytosiderophore release has been linked to ability of species and genotypes to resist Fe‐deficiency chlorosis. We propose a laboratory technique to measure phytosiderophore release by Fe‐deficient oat (Avena sativa L.) genotypes as a selection method for Fe‐deficiency chlorosis resistance in oat. Plants were grown in Fe‐limiting nutrient solution and phytosiderophore release was measured on 11 days. Summations of daily phytosiderophore release by 17 oat genotypes correlate well with Fe‐deficiency chlorosis scores in the field (r = ‐0.70, p = 0.01). The proposed method consistently identified the genotypes most susceptible to Fe deficiency but did not clearly separate the moderately susceptible genotypes. In these latter genotypes, other factors such as active uptake sites, root growth rate, utilization of acquired Fe, or soil interactions may be modifying factors to phytosiderophore in Fe efficiency. Quantification of phytosiderophore provides a useful selection criterion for oat by eliminating the most inefficient types and with refinement, may become a powerful tool for identifying Fe efficiency in grass crops.     

Solubility Relationships of Iron and Evaluation of its Fertility Status in Degraded Soils

This study was conducted to determine the solubility of iron (Fe) and identify the solid phases responsible for controlling its solubility in these soils by using Baker soil test (BST) computer program. The results indicated that the ferric ion (Fe³⁺) activity in all the soils, except the acidic ones, nearly approached the theoretical solubility line of known minerals, namely soil-Fe, amorphous-Fe, maghemite, and lepidocrocite. Solubility of Fe in acid soils of Ranchi (soil 3) and Cooch-Behar (soil 6) did not match the theoretical solubility lines of any of the known minerals. The acidic soils of Ranchi and Cooch-Behar were sufficient for Fe with respect to both quantity and intensity factor based on BST rating, while alkaline (soil 1) and calcareous (soil 5) were sufficient in reserve Fe; deficiency of iron still could be suspected because of high pH. These findings elucidate the role of solid phase controlling iron solubility in soil solution of degraded soils.     

Comparing Soil and Tissue Testing of Copper for Early Growth of Wheat

Abstract

About 40% of soils used for agriculture in southwestern Australia (SWA) were acutely copper (Cu) deficient when first cleared, and Cu fertilizer needed to be applied to grow the first wheat (Triticum aestivum L.) crop, the major crop in the region. Tissue testing rather than soil testing is used in SWA to indicate when fertilizer Cu needs to be reapplied to wheat crops. In a glasshouse study using six Cu‐deficient soils from SWA, we compared four Cu soil test procedures as possible alternatives to tissue testing to predict Cu deficiency for wheat. Different critical values were obtained for different soils for all four soil test procedures, indicating separate soil test calibrations would be required for the four procedures for different soils in SWA. By contrast, critical tissue test values in plant parts (young leaves and rest of shoots) were unaffected by soil type. Developing soil Cu test calibrations would be time consuming and costly, and tissue testing has resulted in most deficiency being corrected by fertilizer applications, so there are few Cu‐deficient soils in SWA available to develop the soil test calibrations. Therefore, tissue testing using young leaves is likely to remain the most reliable method for diagnosing Cu deficiency for wheat in SWA and determining when reapplication of fertilizer Cu to soil is required.     

Effects of exogenous SA supplied with different approaches on growth,chlorophyll content and antioxidant enzymes of peanut growing on calcareous soil

To assess the role of salicylic acid (SA) supplied with 5 approaches in alleviating chlorosis induced by iron (Fe) deficiency in peanut plants growing on calcareous soil, SA was supplied as soil incorporation, making slow-release particles, seed soaking, irrigation and foliar application. SA application, particularly, SA supplied by slow release particles, dramatically increased growth parameters, yield and quality of peanut, and increased Fe concentration in peanut grain. Meanwhile, SA application increased the H⁺-ATPase activity, reduced pH of soil, increased Fe³⁺-Chelate Reductase (FCR) activity in roots, and increased Fe concentration in roots. Furthermore, SA increased active Fe content and increased chlorophyll content. In addition, SA improved enzymes activities containing superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and protected Fe deficiency induced oxidative stress. Therefore, SA has a good effect on alleviating chlorosis induced by Fe deficiency on calcareous soil. However, in the 5 SA supplied approaches, foliar application and making slow release particles were more effective.     

Iron chlorosis in macadamia as affected by phosphate‐iron interactions 1

Iron (Fe) chlorosis induced by heavy phosphate (P) fertilizations is a serious problem for macadamia (Macadamia integrifolia) in Hawaii. To address this problem, a study was conducted to quantify the effects of P‐Fe interaction on macadamia leaf composition and chlorosis. The soil used was a limed Oxisol (Tropeptic Eutrustox, Wahiawa Series), pH 5.5. Phosphate was added as treble superphosphate at 0, 150 and 500 mg P/kg. The 150 mg P/kg rate was designed to yield approximately 0.04 mg P/L in the soil solution, a level considered adequate for macadamia growth. The 500 mg P/kg rate was intended to produce approximately 0.2 mg P/L, a level required by many horticultural crops but considered excessive for macadamia. Iron was added as Fe‐DTPA at 0, 5 and 10 mg Fe/kg soil, and factorially imposed on the P treatments. Color Index, a numerical rating based on hue, value and chroma from a Munsell Color Chart for Plant Tissues, was correlated with leaf chlorophyll concentration and used as an indicator of chlorosis.

Phosphate concentrations in leaves increased with increasing P application rates as expected, but decreased remarkably with increasing Fe rates (at a constant P rate). Plant Fe unexpectedly remained unchanged with increasing Fe rates but decreased with increasing P rates. The results suggest that (1) soil‐solution Fe was not a limiting factor to macadamia growth as is often incorrectly assumed for high P‐fertilized soils, (2) Fe uptake was restricted not because soil‐solution Fe was low but because plant P was excessively high, and (3) Fe translocation from roots to leaves may have been hampered by high P in the plants. Consequently, Fe chlorosis was intensified primarily by P fertilization (actually, by high plant P concentrations) and secondarily by P‐Fe interactions. Chlorosis, as measured by Color Index, can be diagnosed by a leaf Fe/P ratio < 0.06, and predicted by a soil‐solution ³√Fe/P ratio < 15.     

Iron deficiency Chlorosis in peppers

A yellow‐fruited inbred pepper cv. ‘Zehavi’, was found to be highly chlorotic on a previously non‐cultivated calcareous soil in the Arava Valley (Israel) during winter 1981–1982. Foliage symptoms and a test for diagnosing iron indicated iron deficiency, soil application of Fe EDTA corrected the symptoms in the field. When ‘Zehavi’ was sown at the same location, in the winter of 1982–1983, but on calcareous soil which had previously been cultivated for several years, no chlorosis appeared. Inheritance studies indicated recessive control for iron deficiency chlorosis but complete genetic interpretation is suggested only under controlled iron deficiency conditions.     

Studies on the magnesium metabolism of crops (Part 1) the balance among magnesium,calcium and pot assLum in free and bound forms at the flowering stage of soy-bean plants

In the later nineteenth century, it was established that magnesium is one of the essential elements to plant life. In 1902 Loew¹⁾ and his pupils suggested the necessity of calcium-magnesium- balance in culture solution for the proper growth of the plant. Then, in 1906, it was established that, as first shown by Willstatter, magnesium is one of the constituents of chlorophyll and when this element is lacking, a chlorosis occurs. Dickson²⁾, in 1918, described about the feature of oat plant grown in a magnesium deficient nutrient solution. At that time, it was thought that magnesium was generally contained in the soil more abundantly than the plant required. So this element scarcely received attention. Garner et al.³⁾, in 1923, observed that chlorosis of tobacco plant, so-called sand drown was cured by applying magnesium to the soil. Similar observation was made in 1929 by Jones⁴⁾ on the chlorosis of corn plant. Since that time the magnesium deficiency in all crops was observed everywhere by a great many investigators. In Japan magnesium deficiency in the field has attracted attention from 1951.     

Prevention of Iron‐Deficiency Induced Chlorosis in Kiwifruit (Actinidia deliciosa) Through Soil Application of Synthetic Vivianite in a Calcareous Soil

Abstract

In this study we have tested the hypothesis that lime‐induced Fe deficiency chlorosis of kiwifruit may be prevented by the application of a synthetic iron(II)‐phosphate analogous to the mineral vivianite [(Fe₃(PO₄)₂·8H₂O)]. Two experiments, under greenhouse and field conditions, were performed. In the greenhouse, 1‐year old micropropagated plants (Actinidia deliciosa, cv. Hayward), grown in 3‐L pots on a calcareous soil, were treated in early autumn with soil‐applied: (1) synthetic vivianite (1.35 g plant^?1) and (2) Fe‐EDDHA (24 mg Fe plant^?1). The synthetic vivianite suspension, prepared by dissolving ferrous sulfate and mono‐ammonium phosphate, was injected into the soil as a sole application whereas the Fe‐EDDHA solution was applied four times at weekly intervals. The field experiment was conducted in a mature drip‐irrigated kiwifruit orchard located on a calcareous soil in the Eastern Po Valley (Italy). Treatments were performed in early autumn by injecting synthetic vivianite (1.8 kg tree^?1) and Fe‐EDDHA (600 mg Fe tree^?1) into four holes in the soil around each tree, at a depth of 25–30 cm. The Fe‐chelate application was repeated at the same rate in the following spring. Untreated (control) plants were used in both experiments. Autumn‐applied Fe fertilisers significantly prevented development of Fe chlorosis under greenhouse conditions whereas in the field only vivianite was effective. In conclusion, these 1‐year results show that vivianite represents an effective alternative to soil‐applied Fe chelates for preventing Fe chlorosis in kiwifruit orchards.