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1.
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 (Feo) was the most useful simple variable to predict the occurrence of Fe chlorosis. A Feo/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.  相似文献   

2.
Previous pot cropping and laboratory incubation experiments were consistent with field observations showing that temporary flooding before cropping can increase the availability of soil Fe to plants. To study the effect of temporary flooding on changes in soil Fe phytoavailability we used 24 highly calcareous, Fe chlorosis–inducing soils to carry out a pot experiment where peanut and chickpea were successively grown after flooding for 30 d. At the end of the cropping experiment, the preflooded soil samples exhibited higher concentrations of acid oxalate‐, citrate/ascorbate‐ and diethylenetriaminepentacetic acid (DTPA)–extractable Fe (Feox, Feca, and FeDTPA, respectively) than the control (nonflooded) samples. Also, Feox and Feca exhibited no change by effect of reflooding of the cropped soils or three wetting–drying cycles in freeze‐dried slurries of soils previously incubated anaerobically for several weeks. Leaf chlorophyll concentration (LCC) in both peanut and chickpea was greatly increased by preflooding. The best predictor for LCC was Feox, followed by Feca and FeDTPA. The LCC–soil Fe relationships found suggest that the Fe species extracted by oxalate and citrate/ascorbate from preflooded soils were more phytoavailable than those extracted from control soils. However, the increased phytoavailability of extractable Fe forms was seemingly limited to the first crop (peanut). Flooding dramatically increased FeDTPA; however, high FeDTPA levels did not result in high LCC values, particularly in the second crop. Therefore, this test is a poor predictor of the severity of Fe chlorosis in preflooded soils.  相似文献   

3.
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.  相似文献   

4.
《Journal of plant nutrition》2013,36(10):2205-2228
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.  相似文献   

5.
Peanut (Arachis hypogea cv. Shulamit) grown on very high calcium carbonate (CaCO3) content soils is showing iron (Fe) chlorosis symptoms. Supplying the plant with ammonium sulphate ((NH4)2SO4) in the presence of nitrapyrin (N‐Serv) for preventing nitrification reduced Fe chlorosis. Nitrate (NO 3) developed in the soil with time, even with nitrapyrin present. When ammonium (NH+ 4) was even less than 20% of the total mineral N in the soil, no Fe‐stress could be observed, suggesting that the NH+ 4 uptake by the plant and the consequence of hydrogen (H+) efflux occurs from the root to the rhizosphere, resulting in a decrease of redox potential near the root, and solubilizing enough Fe near the root to overcome the chlorosis.  相似文献   

6.
Abstract

Phosphorus sorption studies were conducted on volcanic ash influenced surface horizons of 29 northern Idaho soils. Results show that the amount of P sorbed was significantly correlated with citrate‐dithionite extractable aluminum (r = .64**), but not with Fe. Other significantly correlated soil properties were: percent base saturation (r = ‐.73**), percent clay (r = .42**), and exchangeable acidity (r = .39*).  相似文献   

7.
Extensive areas of chlorotic winter wheat (Triticum aestivun L.) were observed on calcareous soils in western Oklahoma. Spraying severely chlorotic wheat with ferrous sulfate (FeSO4) resulted in greening within a week and doubled herbage yield a month later. Intensive grazing of wheat prior to jointing induced no to severe chlorosis in 33 wheat cultivars tested over three years. After peak intensity in early April, the chlorosis diminished and was not visible when the wheat was fully headed in May. Overall, we believe increased iron (Fe) deficiency in wheat on the Southern Plains is due to increased use of Fe‐inefficient cultivars and stress induced by grazing. Wheat cultivars less susceptible to Fe deficiency are commercially available.  相似文献   

8.
This study investigated those soil factors related to iron (Fe) chlorosis between Fe status of peach leaves and some soil properties in the Antalya region of Turkey. The total Fe content of leaves was negatively correlated with soil pH and the organic matter content of the soils. Extractable Fe (by 1N HCl) was negatively correlated with the calcium carbonate (CaCO3) and bicarbonate (HCO3‐) content of the soils. In addition, both total‐ and extractable‐Fe contents of leaves were also negatively correlated with the copper (Cu) content of the soils. On the other hand, significant correlations were found among the Fe index, P/Fe ratio of leaves, and soil pH, phosphorus (P), zinc (Zn), and Cu content of the soils. It appears from these studies that high pH, and the CaCO3, HCO3‐, and Cu contents are effective soil factors affecting the availability of Fe and its uptake by the peach trees, and these soil factors were associated with severity of Fe chlorosis in the studied area.  相似文献   

9.
Abstract

A new soil extractant (H3A) with the ability to extract NH4, NO3, and P from soil was developed and tested against 32 soils, which varied greatly in clay content, organic carbon (C), and soil pH. The extractant (H3A) eliminates the need for separate phosphorus (P) extractants for acid and calcareous soils and maintains the extract pH, on average, within one unit of the soil pH. The extractant is composed of organic root exudates, lithium citrate, and two synthetic chelators (DTPA, EDTA). The new soil extractant was tested against Mehlich 3, Olsen, and water for extractable P, and 1 M KCl and water‐extractable NH4 and NO2/NO3. The pH of the extractant after adding soil, shaking, and filtration was measured for each soil sample (5 extractants×2 reps×32 soils=320 samples) and was shown to be highly influential on extractable P but has no effect on extractable NH4 or NO2/NO3. H3A was highly correlated with soil‐extractable inorganic N (NH4, NO2/NO3) from both water (r=0.98) and 1 M KCl (r=0.97), as well as being significantly correlated with water (r=0.71), Mehlich 3 (r=0.83), and Olsen (r=0.84) for extractable P.  相似文献   

10.
Iron (Fe) deficiency has been a widespread problem in peanut (Arachis hypogaea L.) grown on calcareous soils of northern China and has resulted in significant yield losses. Field observations showed considerable variability in visual chlorosis symptoms among peanut cultivars in the same soil. The objective of this study was to confirm the genetic differences in resistance to Fe-deficiency chlorosis in peanut and to identify feasible indicators for screening Fe-efficient genotypes. Resistance to Fe chlorosis of sixteen peanut cultivars grown on calcareous soil was evaluated in the field and physiological responses to Fe-deficiency stress were studied in nutrient solution. There were significant differences in resistance to Fe-deficiency chlorosis among the sixteen peanut cultivars tested, which was identified with SPAD readings, active Fe concentrations in young leaves in the early growth stages, and the pod yield. For Fe-resistant peanut cultivars, Fe-reduction capacity and quality of releasing hydrogen ions from roots increased under Fe-deficiency stress. Highly correlated relationships were observed between the summation of root Fe reduction and field chlorosis scores for sixteen cultivars (r2 = 0.79). It was concluded that Fe-reduction capacity was a better physiological indicator for screening Fe-efficient peanut genotypes of the mechanisms measured.  相似文献   

11.
Abstract

A procedure for the simultaneous extraction of phosphorus, potassium, calcium and magnesium from soils, by an ion‐exchange resin procedure applicable to large‐scale advisory soil testing, is described. The important steps are the disaggregation of soil by shaking in water during 15 minutes with a glass marble, the transference of the elements from the soil to a sodium bicarbonate treated mixture of anion and cation exchange resins during a 16‐hour shaking period, the separation of the resin from the soil by sieving and extraction of the elements from the resin.

The results of resin extractable calcium, magnesium and potassium were comparable to the results of these elements extracted with 1M NH4OAc, to calcium and magnesium extracted with 1M KCl, and to potassium extracted with 0.025M H2SO4.

For phosphorus the resin extractable values were not comparable to the results obtained by the former routine method, based on the extraction with 0.025M H2SO4. The results of resin extractable P presented closer correlation with cotton response to phosphorus application in 28 field experiments (r = 0.85**) as compared with 0.025M H2SO4 extractable P (r = 0.68**), and also with P uptake by flooded rice in a pot experiment with eight lowland soil samples (r = 0.98**), as compared with extraction with 0.0125M H2SO4 in 0.050M HCl, for which the correlation was not significant. The reasons for the superiority of the extraction of P with the described procedure are discussed.  相似文献   

12.
Phosphate sorption was studied in samples (0 - 20 cm depth) of five soils from Egypt (pH 7.4 - 8.7), four soils from Ethiopia (pH 3.9 - 5.3) and six soils from Germany (pH 3.3 - 7.2). Sorption parameters were calculated according to Pagel and Van Huay (1976) and according to Langmuir (Syers et al., 1973). Phosphate sorption parameters and oxalate extractable Fe and Al (Feox, Alox) were related to the phosphate uptake by young rye plants in Neubauer pot experiments. P sorption parameter after Pagel and Van Huay (A) correlated significantly positively with the Feox and Alox content in acid (r = 0.73) as well as in calcareous soils (r = 0.89) if the whole equilibrium concentration range (0 - 14 mg P/L) was considered. The relations calculated after Langmuir (B) were similar. P uptake by rye in acid soils was negatively correlated with the affinity constant n (r = ?0.76, (A)). In calcareous soils, a negative correlation between P uptake and affinity constant was calculated in the lower P equilibrium range (0 - 2.8 mg P/L) only for (B). Thus, P uptake decreased with increasing strength of P bonding to soil. From these results it is concluded that phosphate sorbed to Fe/Al oxides is an important P source for plants in acid and calcareous soils.  相似文献   

13.
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.  相似文献   

14.
Abstract

Molybdenum (Mo) is an essential element of plants and animals and is of concern from human nutrition and environmental standpoints. Rational applications to soil of Mo in fertilizers, sewage sludges, or other soil amendments requires information of the concentrations of Mo in soils and plants. Two greenhouse experiments were conducted at Lexington, Kentucky, using surface samples of 12 soils (11 soil types) derived from diverse parent materials in Kentucky with soil pH ranging from 5.18 to 7.46. Molybdenum (Na2MoO4.2H2O) was added at rates equivalent to 0, 0.3, and 0.6 mg Mo kg‐1 soil. Tobacco (Nicotiana tabacum L., cv. Ky14) and soybean [Glycine max. (L.) Merrill cv. McCall] were grown to provide plant Mo data for Mo soil test correlations and comparisons. The primary purpose of these investigations was to determine the effect of pH of NH4‐oxalate extractant solution on the relationship of soil Mo and Mo uptake by tobacco and soybeans, and to evaluate the automated KI‐H2O2 procedure for use in determining Mo in soil extracting solutions. The mean dry weight and Mo concentration of tobacco and soybean were increased by applications of Mo fertilizer to soil in the greenhouse. Dry matter of tobacco was increased 11 to 25% and concentration of Mo from 40 to 82% by each increment of added Mo fertilizer. The results of this study suggest that many soils in Kentucky are not meeting the requirements for Mo sufficiency for tobacco and soybean plants. The average amount of soil Mo extracted by NH4‐oxalate decreased with increasing pH of extractant. Regression estimates for the relationship of Mo uptake by tobacco or soybean and extractable soil Mo show that the slope and the coefficients of determination increased with pH of NH4‐oxalate solution from pH 3.3 to 6.0 and then decreased again at pH 6.4. The greatest amounts of variation in Mo uptake by plants (67% and 20%, respectively, for tobacco and soybean) were accounted for by the soil Mo data at pH 6.0. Soil Mo values for the NH4‐oxalate extractant (pH 6.0) were related to values for anion exchange resin extractant (r2 = 0.61**), but not soil pH. However, values for anion exchange resin were more closely related to Mo uptake by tobacco (r2 = 0.86**) and soybean (r2 = 0.60**) than were values for NH4‐oxalate (r2 = 0.65** and r2 = 0.27**, respectively). Results of this study indicate that the automated KI‐H2O2 method used previously in analysis for plant Mo can be used to analyze Mo in soil extracts. Other instrumentation such as GFAAS and ICP may be effective in the analysis of extracts obtained by the NH4‐oxalate (pH 6.0) or by anion exchange resin procedures when the Mo concentration of extracts falls within the detection limits of the instrument.  相似文献   

15.
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.  相似文献   

16.
Extraction with acid NH4-oxalate is widely used to estimate the content of “active” forms of Fe oxides in soil. In calcareous soils, this extraction presents some problems (pH change, production of CO2), which have been circumvented by decalcifying the soil before extraction. However, because of its tediousness, this procedure cannot be applied for routine purposes. In this paper, we describe a rapid procedure in which the soil is treated with oxalic acid before oxalate extraction to neutralize the active calcium carbonate equivalent. The method is simple and provides a useful estimation of the content of active Fe forms that are not occluded in the coarse particles and aggregates of carbonate.  相似文献   

17.
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.  相似文献   

18.
Abstract

Highly calcareous soils are abundant in Iran. The calcium carbonate equivalent (CCE) of these soils reach up to 650 g kg?1. Although phosphorus (P) fertilizer is being widely used in these soils, little information, if any, is available about P status in such soils. The objectives of this study were to 1) determine inorganic P forms in 18 surface soils of southern Iran, 2) study P readsorption during different stages of fractionation schemes, 3) assess the ability of NaOH to extract aluminum (Al)‐P, and 4) evaluate the relationships between P availability indices and inorganic P forms. Eighteen soil samples with a wide range of physicochemical properties were selected for this study. Inorganic P forms was determined by sequential extraction with NaHCO3, NH4OAc, NH4F, NaOH, citrate dithionite (CD), and H2SO4, which are referred to as Ca2‐P, Ca8‐P, Al‐P, Fe‐P, occluded P (O‐P), and Ca10‐P. Phosphorus readsorption in different stages was determined by 1 M MgCl2. Furthermore, a fractionation scheme without an NH4F step was used to evaluate the ability of NaOH to extract Al‐P. NaHCO3 (Olsen‐P) and MgCl2‐extractable P (Exch‐P) were regarded as P-availability indices. The abundance of different P forms was in the order Ca2‐P<Fe‐P<Al‐P<O‐P<Ca8‐P<Ca10‐P. Ca2‐P was highly correlated with Olsen‐P and Exch‐P. Ca2‐P, Olsen‐P, and Exch‐P showed a relationship with CCE, citrate–bicarbonate–dithionite extractable Fe (Fed), and Al (Ald). Phosphorus readsorption appeared to be important only in the Ca8‐P step, and the content of readsorbed P was related to Ca8‐P, CCE, and clay content of the soils. In the present study, Al‐P and Fe‐P accounted for 10 and 5% of the sum of the inorganic P fractions, respectively, and Fe‐P showed a strong relationship with Feo, whereas Al‐P showed a significant relationship with oxalate‐extractable Al (Alo) and Ald. It was found that one extraction with NaOH is not a good indicator for Fe‐ and Al‐P, and the ability of NaOH to extract Al‐P was reduced with increase in Al‐P content.  相似文献   

19.
An attempt was made to study the effects of sulfuric acid additions to iron (Fe)‐ and phosphorus (P)‐deficient calcareous soils. Several greenhouse experiments were conducted with sorghum (Sorghum bicolor L.) grown in two calcareous soils. Addition of sulfuric acid to soils increased soil acidity, salinity, DTPA‐extractable Fe, available P (NaHCO3‐extractable), and crop yield. The change in soil pH is the primary cause of increased nutrient availability and thus crop yield. Leaching after acid application is highly beneficial in decreasing salinity during germination and seedling stages and therefore has a direct impact on the yield. The beneficial effects of acid carried over for at least two greenhouse cropping seasons (approximately 4.5 months).  相似文献   

20.
Abstract

Hardsetting soil properties are undesirable in agricultural soils because they hamper moisture movement and soil aeration. The soils of the floodplain of Niger River in eastern Nigeria hardsets upon drying, following dispersion, puddling, and slaking during the waterlogged period. Ten soil samples collected from a depth of 0–20 cm were analyzed for their properties. The soils are classified as Fluvaquentic Eutropepts or Dystric Gleysol (FAO). The objective was to investigate the influence of some soil properties on water‐dispersible clay (WDC) of the soils, which is the precursor of the hardsetting process. The total clay content (TC) correlated significantly with WDC (r=0.94??), whereas the water‐dispersible silt (WDSi) was higher than its corresponding total silt content. The WDC showed a positive correlation with dithionite extractable Fe (Fed), Al (Ald), and oxalate extractable Fe (Feo) (r=0.75?, 0.89??, and 0.76? respectively). Exchangeable Mg2+ correlated significantly with WDSi (r=0.70). Principal component analysis of the soil variables indicates that 15 soil components, which influence WDC as hardsetting properties, were reduced to 5 orthogonal components. The parameters that influence hardsetting properties are exchangeable Na+, K+, Ca2+, Mg2+, Fed, Alo, and Feo. Other soil properties are kaolinite, smectite, illite, and WDC, including soil organic carbon (OC), electrical conductivity (EC), and ESP. Therefore, those soil properties, which explain hardsetting characteristics most, are exchangeable Na+, Fed, OC, Mg2+, and Alo. There are negative consequences on the erodibility, runoff, infiltration and tillage of the soils at both submerged and dry conditions due to clay dispersion, low OC, and hardsetting behavior of the soil.  相似文献   

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