Correction of iron chlorosis in peanut (arachis hypogea shulamit) by ammonium sulfate and nitrification inhibitor

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.     

Ability of an iron‐efficient and an iron‐inefficient corn inbred to take up 59Fe and FeSO4 added to Yolo loam soil

Abstract

The addition of CaCO₃ and MgCO₃ to Yolo loam soil (pH 6) resulted in lower Fe concentrations in shoots of the Fe‐inefficient Ys₁/Ys₁ corn inbred (Zea mays L.) and higher levels in shoots of the Fe‐efficient WF9 inbred than in controls. When ⁵⁹Fe with and without carrier FeSO₄ was blended with the soil, the specific activity was similar for the two inbreds in nonamended soils, but was increased in the Ys₁/Ys₁ for the lime amendments. Sulfur acidification of soil decreased the specific activity of ⁵⁹ Fe in shoots by increasing the pool of available Fe. From 5 to 33% of the Fe in plants came from the FeSO₄ source. It was greatest in Ys₁/Ys₁ with lime‐amended soils and least in S‐acidified soil.     

Factors related to iron uptake by dicotyledonous and monocotyledonous plants. I. pH and reductant

Some plants respond to Fe‐deficiency stress by inducing Fe‐solubilizing reactions at or near the root surface. In their ability to solubilize Fe, dicotyledonous plants are more effective than monocotyledonous plants. In this study we determined how representative plants differ in their response when subjected to Fe‐deficiency stress in a calcareous soil and in nutrient solutions. Iron‐inefficient genotypes of tomato, soybean, oats, and corn all developed Fe chlorosis when grown in soil, whereas Fe‐efficient genotypes of these same species remained green. The same genotypes were grown in complete nutrient solutions and then transferred to nutrient solutions containing N (as NO₃ ^‐) and no Fe.

The T3238 FER tomato (Lycopersican esculentum Mill.) Fe‐efficient) was the only genotype that released significant amounts of H from the roots (the pH was lowered to 3.9) and concomitantly released reductants. Under similar conditions, Hawkeye soyhean [Glycine max (L.) Merr.] released reductants but the solution pH was not lowered. Both Fe‐inefficient and Fe‐efficient genotypes of oats (Avena sativa L.) and corn (Zea mays L.) released insufficient H or reductant from their roots to solubilize Fe; as a result, each of these genotypes developed Fe‐deficiency (chlorosis).

The marked differences observed among these genotypes illustrate the genetic variability inherent within many plant species. A given species or genotype may accordingly not be adapted to a particular soil. Conversely, a given species or genotype may be found (or developed) that is precisely suited for a particular soil. In this event, the need for soil amendments may be reduced or eliminated.     

Underestimation of Available Phosphorus by Resin–Bicarbonate and Olsen Tests in Calcareous Soils treated with Gypsum

In the present study, Olsen [0.5 M sodium bicarbonate (NaHCO₃), pH 8.5] and resin–bicarbonate (HCO₃) tests underestimated available phosphorus (P) in calcareous soils treated with gypsum (CaSO₄). The reaction of CaSO₄ and HCO₃ ^? ion or resin–HCO₃ to form calcium carbonate (CaCO₃) precipitate reduced the strength of the Olsen NaHCO₃ extractant and resin–HCO₃ strip for P extraction. The iron (Fe) oxide–impregnated filter paper (Pi strip) was independent of CaSO₄ influence and thus correctly estimated soil‐available P with respect to plant response to soil‐available P. Two greenhouse experiments were conducted with maize and wheat grown on calcareous soils treated with different rates of CaSO₄. The results confirmed that Olsen and resin–HCO₃ tests should not be used to measure available P or labile P in the P fractionation scheme in the calcareous soils containing significant amounts of gypsum.     

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.     

外加碳酸盐增加石灰性土壤密闭培养过程中CO2的释放量

The closed-jar incubation method is widely used to estimate the mineralization of soil organic C. There are two C pools (i.e., organic and inorganic C) in calcareous soil. To evaluate the effect of additional carbonates on CO2 emission from calcareous soil during closed-jar incubation, three incubation experiments were conducted by adding different types (CaCO3 and MgCO3 ) and amounts of carbonate to the soil. The addition of carbonates significantly increased CO2 emission from the soil; the increase ranged from 12.0% in the CaCO3 amended soil to 460% in the MgCO3 amended soil during a 100-d incubation. Cumulative CO2 production at the end of the incubation was three times greater in the MgCO3 amended soil compared to the CaCO3 amended one. The CO2 emission increased with the amount of CaCO3 added to the soil. In contrast, CO2 emission decreased as the amount of MgCO3 added to the soil increased. Our results confirmed that the closed-jar incubation method could lead to an overestimate of organic C mineralization in calcareous soils. Because of its effect on soil pH and the dissolution of carbonates, HgCl2 should not be used to sterilize calcareous soil if the experiment includes the measurement of soil CO2 production.     

Factors related to iron uptake by dicotyledonous and monocotyledonous plants III. Competition between root and external factors for Fe

In comparison studies (11, 12), monocotyledonous corn (Zea mays L.) and oats (Avena byzantina C. Koch) did not respond to Fe stress as effectively nor to the same degree as the dicotyledonous soybeans (Glycine max (L.) Merr.) or tomatoes (Lycopersicon esculentum Mill.). Both the Fe‐inefficient and Fe‐efficient corn and oats developed Fe chlorosis; the Fe‐efficient dicotyledonous plants were green. In the present study, the method of inducing Fe stress was changed to make it less severe. Instead of using only NO₃‐N and no Fe to induce Fe stress (11, 12), both NH₄‐N and NO₃‐N were used along with varied concentrations of Fe. Iron stress was induced with BPDS (4,7‐diphenyl‐l, 10‐phenan‐throline disulfonic acid) and phosphate; both competed with the plant for Fe. Phosphate also inhibits reduction of Fe³⁺ to Fe²⁺ (12). This method of inducing Fe stress in the plants was less severe than using only NO₃‐N and no Fe in the nutrient solutions and we were able to measure a difference in Fe‐stress response for all four plant species (Fe‐inefficient and Fe‐efficient). At the lower Fe treatments, the roots of Fe‐efficient plants usually reduced more Fe³⁺ to Fe²⁺ than did the roots of Fe‐inefficient plants. The ‘inefficient’ ys₁ corn and TAM 0–312 oat roots did not compete with BPDS or phosphate for Fe as effectively as did the ‘efficient’ WF9 corn and Coker 227 oat roots. The same type mechanism for solubilization, absorption, and transport of Fe seems to function in both monocotyledenous and dicotyledenous plants but it is more effective and more readily detected in the dicot than in the monocot plants. The reactions involved in reduction of Fe³⁺ to Fe²⁺ seemed to be confined inside or at the root surface for the inefficient genotypes; the efficient genotypes alter the ambient medium to a greater degree.     

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.     

Monocot‐dicot variability in response to an iron oxide‐metallic iron source

Abstract

Iron from a mixture of Fe oxide and metallic Fe was more available to corn (Zea mays L.) than it was to soybeans when the plants wore grown in calcareous soil or in nutrient solution. All this Fe, however, was DTPA (diethylene triamine pentaacetic acid) extractable. In solution culture the Fe was available to the soybean (Glycine max L.) plants unless CaCO₃ was included in the nutrient solution.     

Root reductant release as a measure of sorghum cultivar iron efficiency

Measurement of root reductant levels developed during plant Fe stress was tested as a possible assay for sorghum cultivar Fe‐efficiency screening. Iron‐stressed sorghum was shown to release reductants into CaCO₃ buffered nutrient solution; however, considerably more plants could be tested by extracting reductants from excised roots of Fe‐stressed sorghum in 35 ml of pH 3 nutrient solution and 1 mM glucose. An Fe‐efficient cultivar, RT×2536, and an Fe‐inefficient cultivar, BT×378, could be separated by measurement of reductants released into CaCO₃ buffered nutrient solution and by an excised root extraction method; however, neither method was as effective as visual rating methods.     

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.     

The effect of lime on the response of soils to sodic conditions

The role of CaC0₃ in preventing clay dispersion and losses in hydraulic conductivity (HC) of sodic soils was determined directly by mixing two lime-free soils with 0.5 and 2.0 per cent CaCO₃. Whereas the HC of the lime-free soils dropped sharply when 0.01 n solutions of SAR 20 were displaced with distilled water, mixing the soils with powdered lime prevented both HC losses and clay dispersion. The response of a sandy soil mixed with lime was similar to that of a calcareous sandy soil. The beneficial effect ofCaC0₃ was not so pronounced in soils equilibrated with solutions of SAR 30. The increase in electrolyte concentration, due to CaCO₃ dissolution, was suggested as the mechanism responsible for the beneficial effect of lime.     

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.     

Short‐Term Effect of Lime,Phosphorus, and Iron Amendments on Water‐Extractable Lead and Arsenic in Orchard Soils

Abstract

Lead arsenate was extensively used to control insects in apple and plum orchards in the 1900s. Continuous use of lead arsenate resulted in elevated soil levels of lead (Pb) and arsenic (As). There are concerns that As and Pb will become solubilized upon a change in land use. In situ chemical stabilization practices, such as the use of phosphate‐phosphorus (P), have been investigated as a possible method for reducing the solubility, mobility, and potential toxicity of Pb and As in these soils. The objective of this study was to determine the effectiveness of calcium carbonate (lime), P, and iron (Fe) amendments in reducing the solubility of As and Pb in lead‐arsenate‐treated soils over time. Under controlled conditions, two orchard soils, Thurmont loam (Hapludults) and Burch loam (Haploxerolls), were amended with reagent‐grade calcium carbonate (CaCO₃), iron hydroxide [Fe(OH)₃], and potassium phosphate (KH₂PO₄) and incubated for 16 weeks at 26°C. The experimental results suggested that the inorganic P increased competitive sorption between H₂PO₄ ^? and dihydrogen arsenate (H₂AsO₄ ^?), resulting in greater desorption of As in both Thurmont and Burch soils. Therefore, addition of lime, potassium phosphate, and Fe to lead‐arsenate‐contaminated soils could increase the risk of loss of soluble As and Pb from surface soil and potentially increase these metal species in runoff and movement to groundwater.     

Effects of floating Azolla on phosphorus fluxes and recovery from former agricultural lands in wetland microcosms

The long-term fertilization results in accumulation of phosphorus especially in the top layer of the soils. Inundation of agricultural lands leads to a switch to anaerobic soil condition, causing reduction of iron and leaching of phosphate simultaneously. From the ecological and environmental perspective, high nutrients flux especially phosphorus will increase the possibility of eutrophication in aquatic system. The fern Azolla had a good potential to adsorb phosphorus, it also has distinctive nitrogen-fixing capacity. We conducted a 10-week aquarium experiment to investigate the phosphorus release capacity from two agricultural soils in the Netherlands with different Fe and P concentrations but comparable Fe/P ratios. Besides, the research questions rose to whether Azolla could use the mobilized phosphate released from the soils for growth. We also tried to find an effective indicator to estimate the actually phosphate mobilization from sediment to water layer. Results showed that the soils with high Fe and P concentrations had higher phosphate release rate compared with the soil with low Fe and P concentrations. Pore water Fe: PO₄^3? ratios were valid to identify P release to surface water, when the Fe: PO₄^3? ratios less than 8 mol mol^?1 substantial phosphorus mobilization occurred. The conclusions showed that the actual mobilization of phosphate is more important than the phosphorus retained in the sediments for the internal PO₄^3? fluxes. From 10-week experimental results, we found that Azolla can reuse the phosphate retained in soils thus removed the mobilized phosphate in a moderately low surface water nutrient loading.     

Behavior of iron‐inefficient plants when grown in combinations of calcareous and noncalcareous soils

Abstract

When Fe‐inefficient plants were grown in mixtures of calcareous Hacienda loam soil and noncalcareous Yolo loam soil compared with plants grown in unmixed soils, characteristics and composition of the plants including Fe deficiency were generally intermediate to those with either soil alone. Noncalcareous soil adjacent to calcareous soil allowed PI 54619–5–1 soybeans (Glycine max L.) to obtain sufficient Fe.     

Comparing tests for soil fertility: 1. Conversion equations between olsen and mehlich 3 as phosphorus extractants for 120 soils of south italy

Abstract

The multiple‐element extractant Mehlich 3 (M3) has not been tested extensively in Europe. In this Land, soil‐P test recommendations are based, since decades, on the evaluation of the Olsen‐extractable P, and the optimal soil‐P levels have been established to range between 1.5 and 3.0 mg of Olsen‐P per 100 g of soil. A research programme was started in order to assess the suitability of M3 as routine soil‐P test in European laboratories. As a first approach, we develop conversion equations from Olsen‐P to M3‐P, in order to assess the agreement and the consistency of the measurements under a wide range of chemical and physical soil properties. To this aim, 120 samples with drastically contrasting features were selected within 206 soils collected from all the regions of South Italy. Soil‐P ranges were 0.07–60.53 for M3, and 0.08–21.47 mg/100 g for Olsen. The results showed that M3‐P was a P extractant more efficient than Olsen. The amounts of M3‐P were, on the average, twice as large as the Olsen‐P ones, with mean values of 5.70 and 2.75 mg/100g, respectively. The soil properties exerted a great influence, as well as showed a contrasting effect, on the extraction efficiency of each method. For neutral‐alkaline calcareous soils, the average M3‐P/Olsen‐P ratio increased to 2.52, and the efficiency of M3 poorly varied according to soil pH and CaCO₃ content. On the contrary, in CaCO₃‐free acidic soils, the M3‐P/Olsen‐P ratio decreased to 1.63. In particular, anomalous ratio values less than 1.0 were observed for acidic soils with high content of organo‐mineral complexes with be shifted to 3.7–7.7 for calcareous soils, and to 2.7–4.9 for CaCO₃‐free soils. Field calibrations would give more information to establish the proper values according to either the soil properties and plant requirements. The results encourage the introduction of M3 as routine soil‐P test in our Countries. One must take into account, however, that some soil properties, in particular the CaCO₃ content, migth be considered for a more precise comparative evaluation with existing laboratory data.     

Effects of lime and applied Mn on plant Mn,growth and chlorophyll concentration of ‘Tifway II’ bermudagrass

Abstract

A glasshouse study was conducted to determine effects of lime and Mn applied to three Florida soils on plant Mn, growth, and chlorophyll concentration of ‘Tifway II’ bermudagrass (Cynodon dactylon x Cynodon transvaalensis). Four replications of three lime rates (0, 1000, and 2000 mg CaCO₃/kg as dolomite and Ca(OH)₂ for Astatula fine sand (Typic Quartzipsamment, hyperthermic, uncoated) and Pompano fine sand (Typic Psammaquent, siliceous, hyperthermic); 0, 2000, and 4000 mg CaCO₃/kg as dolomite and Ca(OH)₂ for Myakka fine sand (Aeric Haplaquod, sandy siliceous, hyperthermic) and three Mn applications (none, 10 mg Mn/kg as MnSO₄, and 5 mg Mn/kg as MnEDTA) were used in a randomized, complete block, factorial design. A wide range of plant Mn concentrations existed across treatments for each soil. Differences in plant Mn concentration did not cause significant differences in growth or chlorophyll concentration. The critical plant Mn concentration was not reached, but it appeared to be below 20 mg Mn kg for bermudagrass. Models for prediction of plant Mn concentration using soil pH and extractable soil Mn (Mehlich I, Mehlich II, DTPA‐TEA) were obtained. The applications of MnSO, and MnEDTA each resulted in increased plant Mn under acidic soil conditions. Neither Mn application resulted in increased plant Mn concentration in grass grown on Pompano fine sand with soil pH values of 7.0 or above.     

Effect of sewage sludge on some chemical properties of calcareous sandy soils

Abstract

City sewage sludge was applied to the surface layer (0–10 cm) of two sandy soils, slightly calcareous with 8.9% CaCO₃ and moderately calcareous with 26.7% CaCO₃, at the rates of 0, 25, 50, 75, and 100 Mg ha^‐1. The effects of sewage sludge and its rates on total soluble salts, pH of soils and concentration and movement of some heavy metals within soils were investigated. Soil samples were packed at bulk density of 1.5 g cm^‐3 in PVC columns and incubated for 19 weeks. The results indicated that total soluble salts (EC) of the treated layer increased with increasing sewage sludge rates. Soluble salts also increased with an increase in soil depth for both soils. The pH values of treated layers in two soils decreased with increasing sewage sludge rates. With increasing sewage sludge rates, concentrations of heavy metals [cobalt (Co), nickel (Ni), cadmium (Cd), and leaf (Pb)] increased in the treated layers compared to the untreated layers and their mobility was restricted mostly to the upper 30‐cm depth. Movement of Co and Pb in both the soils was predominately limited up to a depth of 40 cm for Co and 5 cm for Pb below the treated soil layer. Nickel and Cd movement was mostly limited to a depth of 10 cm in slightly calcareous soil and 5 cm in moderately calcareous soil. Metal movement in the respective soils is ranked as Co>Ni=Cd>Pb and Co>Ni=Cd>Pb. The low concentrations of heavy metals and the restricted mobility with soil depth, suggest that this material may be used for agricultural crop production without any toxic effect on plants.     

Heavy‐metal toxicity in plants 1. A crisis in embryo

Abstract

Heavy metals are often added indiscriminantly to soils in pesticides, fertilizers, manures, sewage sludges, and mine wastes, causing an imbalance in nutrient elements in soils. Heavy‐metal toxicity causes plant stress in various degrees dependent on the tolerance of the plant to a specific heavy metal. The objectives of this study were (i) to show that plant species and soils respond differently to heavy metals and (ii) to show the necessity for proper quantity and balance of heavy metals in soils for plant growth.

Three Fe‐inefficient and three Fe‐efficient selections of soybean, corn, and tomato were grown on two alkaline soils with Cu and Zn ranging from 14 to 340 and Mn from 20 to 480 kg/ha. Heavy‐metal toxicity caused Fe deficiency to develop in these plants. The Fe‐inefficient T3238fer tomato and ys₁/ys₁ corn developed Fe deficiency on all treatments and both soils. T3238FER tomato (Fe‐efficient) did not develop heavy metal toxicity symptoms on any treatment or soil. The soybean varieties and WF9 corn were intermediate in their response.

The unpredictable response of both the soil and the plant to heavy metals make general recommendations difficult. In order to maintain highly productive soils, we need to know what we are adding to soils and the consequences. Without some control, the continued addition of heavy metals to soils is a crisis in embryo.