Determining phosphorus needs for cabbage grown on calcareous soils

Cabbage (Brassica olearacea var. capitata L.) yield differences from added P were highly significant up to the predicted response level of 0.4 mg 1 . The increases in yield were basically due to larger head sizes. No statistical differences were found after the soil P levels were adjusted above 0.4 ppm, as determined by P isotherms constructed from initial soil samples. Slight differences occurred between years, but likely were due to cultivar growth differences. Data show that the isotherm predicted level fits rather closely the P requirements for cabbage as related to crop yields. Since extraction methods measure only the intensity factor of P, these methods could lead to incorrect P fertilization recommendations. The absorption of P is progressively reduced as the temperature goes down.     

Potassium,magnesium, and irrigation effects on peanuts grown on two soils

Abstract

Research data are limited on K and Wg requirements of peanuts (Arachis hypogaea L.) grown on sandy soils either with or without irrigation. Purposes of this study were (1) to determine Mg, K, and irrigation effects on yield, sound mature kernels (SMK's), and diseases of ‘Florunner’ peanuts grown on two sandy soils and (2) to determine sufficient amounts of Mg and K in peanut leaves and soils. Field experiments were conducted for three years on a Lakeland sand (thermic, coated Typic Quartzipsainments) and a Fuquay loamy sand (siliceous, thermic, Arenic Plinthic Paleudults). Both soils initially tested low in Mehlich 1 extractable K and Mg, but Lakeland was lower than Fuquay in both K and Mg. Factorial treatments were 0, 67, 67 (split into three applications), and 134 kg Mg/ha as MgS0₄ and 0, 56, 112, and 224 kg K/ha as KC1.

Neither irrigation, K, nor Mg treatment affected number of diseased plants. (Sclerotium rolfsii) or pod rot on either soil. Also, yield and % SMK's were not affected by any treatment any year on Fuquay soil. On Lakeland soil, yields were increased by irrigation 60.3% in 1980 and 11.0% in 1982, by K rates of 56 kg/ha or more each year, and by Mg rates of 67 kg/ha or more in 1978 and 1982. Yields (3‐yr average) were increased 14.7% by Mg with K and 30.7% by K with Mg. Magnesium plus K increased yields 69.3% over the control. Treatments had no consistent effects on % SMK's. Concentrations of K and Mg in leaves and soils were increased by increased rates of application but were not affected by irrigation. Minimum sufficiency levels for maximum yield were 10 and 2.0 g/kg for leaf K and Mg and 20 and 11 ng/kg for soil K and Mg (0 to 30 cm depth), respectively.     

Phosphorus requirement of corn and sunflower grown on calcareous soils of Pakistan

Abstract

Determining phosphorus (P) fertilizer requirement through sorption isotherms is considered more accurate than conventional soil testing. Phosphorus sorption isotherms were constructed by using the Missa (Typic Ustochrept), Gujranwala (Udic Haplustalf), Abbotabad (Aquic Entrochrept), and Rasulpur (Ustochreptic Camborthid) soil series which varied in their calcium carbonate (CaCO₃) and clay contents. Quantities of fertilizer‐P (mg P/kg soil) required to adjust the standard soil solution P concentration (0.2 mg P/L) were: Missa, 83; Gujranwala, 51; Abbotabad, 50; and Rasulpur, 8. Langmuir model conformed better with the adsorption data than Freundlich model and indicated that the order of maximum adsorption capacity (b) was: Missa > Abbotabad = Gujranwala > Rasulpur. The P sorption curves were used to develop the soil solution P concentration in the Gujranwala and Missa soils varying from native to 0.5 mg P/L. Soil solution P requirement of corn and sunflower for near‐maximum (95%) biomass production was approximately the same, 0.32 mg P/L. Internal P requirement in whole shoots (≤30 cm tall) were 0. 29% for corn and 0.39% for sunflower.     

Zinc requirement of corn grown on two calcareous soils of Pakistan

In greenhouse studies, corn (Zea mays L.) growth increased with Zn fertilization of two alkaline calcareous soils. Zinc concentration and total uptake increased with Zn application. Very high correlations were recorded between plant tissue Zn concentration, total Zn uptake and soil Zn levels determined by DTPA and AB-DTPA soil tests. Correlation between Zn concentration in plants and relative yield was poor. However, close relationships were revealed between extractable soil Zn and relative yield. Near maximum dry matter yield of corn was associated with a fertilizer rate of 2 mg Zn/kg soil. Plant tissue Zn-requirement was 27 mg/kg in 15 days old plants and 32 mg/kg in corn shoots of 40 day age. Critical soil test Zn level was 1.2 mg/kg by DTPA and 1.7 mg/kg by AB-DTPA method. Use of AB-DTPA soil test is suggested for evaluating Zn status of calcareous soils.     

The effect of pig slurry on exchangeable potassium in calcareous soils

Pig slurry in quantities of 200, 400, 500, 600, 800, and 1000 m³ ha^-1 year^-1 was added to two calcareous soils, which differed in concentration and type of clay minerals. The soils were cultivated with two successive crops of pepper and tomatoes grown in containers. A control was given no slurry. The soils were analysed after harvesting for exchangeable K⁺. Differences in exchangeable K⁺ were studied in relation to the concentration and type of clay minerals. The soil with the higher clay content and of the illite type retained K in the exchangeable form to a much greater extent than the soil with the low clay content. In the soil with the lower clay content, of the interstratified illitic — montmorillonite type, very little K was incorporated into the exchange complex. The exchange capacity being low, the amount of K added had little effect on the level of exchangeable K⁺.     

Factors affecting potassium fixation in calcareous soils of southern Iran

Potassium fixation capacity and mineralogical analysis of 24 representative soils, collected from southern Iran, were studied. Potassium fixation analysis was performed by adding six rates of K from 0 to 1000 mg kg^?1 soil in a plastic beaker and shaking for 24 h. Mineralogical analysis showed that the clay fractions were dominated by smectite, chlorite, mica, palygorskite, vermiculite and quartz. In general, the studied soils fixed 8.5–55% of the added K. The potassium fixation capacity of the studied soils was significantly correlated with smectite content (r ² = 0.87), clay content (r ² = 0.60), cation-exchange capacity (r ² = 0.79) and NH₄OAc-K. Wetting and drying treatment and incubation time had significant effects on K fixation. The average percentage increase in K fixation following the wetting and drying treatment was 24 and 30% for surface and subsurface soils, respectively. The average percentage increase in K fixation with increasing residence time was 79 and 56% for surface and subsurface soils, respectively. Because K fixation is a diffusion process, time and increased concentration of soluble K (because of soil drying) are factors affecting the rate of K diffusion from a soil solution to the interlayer positions of the expansible 2:1 clay minerals.     

Heavy metal uptake by wheat seedlings grown in fly ash-amended soils

A bioassay technique was used to investigate heavy metals uptake by wheat seedlings grown in fly ash-amended soils. No negative effect of fly ash on the growth of wheat seedlings was found. The addition of the fly ash generally decreased the heavy metal concentration in the wheat seedlings. The total accumulation largely depended on the soil characteristics. The variation in the soil pH induced by the fly ash treatment could be considered the most important parameter that influenced heavy metals uptake. In the soil with a higher increase of pH (2 units) total accumulation of heavy metals decreased with increasing fly ash addition. In the other soils where the pH variation was lower (0.4 units), total accumulation of some heavy metals increased. These obtained data provide useful information which is required before the agronomic use of fly ash can be recommended in Italian soils.     

Calcium carbonate solubilization through H‐proton release from some legumes grown in calcareous saline‐sodic soils

Increasing levels of CO₂ and H⁺ proton in the rhizosphere from some legumes may play an important role in calcite dissolution of calcareous salt affected soils. Soils planted with white and brown varieties of cowpea (Vigna unguiculata L.) and hyacinth bean (Dolichos lablab L.) relying on either fertilizer N (KNO₃) or N‐fixation were compared against soils to which gypsum was applied and a control without plants and gypsum application to study the possibility of Ca²⁺ release from calcite and Na⁺ leaching. As compared to plants relying on inorganic N, leachates from all pore volumes (0·5, 1·0, 1·5, 2·0 pore volume) in lysimeters planted with N‐fixing hyacinth bean contained significantly higher concentrations of HCO with lower concentrations from lysimeters planted with white cowpea relying on N‐fixation. However, the lowest concentrations of HCO were recorded in the gypsum and control treatments. In initial leaching, lysimeters planted with N‐fixing plants maintained similar leachate Ca²⁺ and Na⁺ concentrations compared to gypsum amended soils. However, gypsum amended soils were found to have a prolonged positive effect on Na⁺ removal. It might be concluded that some legumes that are known to fix N in calcareous salt affected soils may be an alternative ameliorant to the extremely expensive gypsum through calcite solubilization and a consequent release of Ca²⁺. Copyright © 2009 John Wiley & Sons, Ltd.     

Short‐term potassium release and fixation in some calcareous soils

Potassium (K⁺) directly released from primary K‐bearing minerals can contribute to plant nutrition. The objective of this research was to assess short‐term K⁺ release and fixation on a range of intensively cropped calcareous soils. Potassium sorption and desorption properties and the contributions of exchangeable‐K⁺ (EK) and nonexchangeable‐K⁺ (NEK) pools to K⁺ dynamics of the soil‐solution system was measured using a modified quantity‐to‐intensity (Q : I) experiment. Release and fixation of K⁺ were varied among soils. The relation between the change in the amount of NEK during the experiment and the initial constrain was linear, and soil ability for K⁺ release and fixation (β) for all soils varied from 0.041 to 0.183, indicating that 4% to 18% of added K⁺ converted to NEK when fixation occurred. The equilibrium potential buffering capacity (PBC) for K⁺ derived from Q : I experiments had significant correlation (r = 0.75, p < 0.01) with β, indicating that PBC depends not only on exchange properties but also on release and fixation properties. The depleted soils showed higher β value than the other soils, indicating much of the added K⁺ was converted to NEK in case of positive constraint. The range of the amount of EK which was not in exchange equilibrium with Ca (E_min) in the experimental conditions was large and varied from 0.68 to 9.00 mmol kg^–1. On average, E_min amounted to 64% of EK. This fraction of EK may not be available to the plant. The parameters obtained from these short‐term K⁺ release and fixation experiments can be used in plant nutrition.     

Influence of sulfur and nitrogen fertilzer on the uptake of iron,manganese, and zinc by corn plants grown in calcareous soil

Abstract

A pot experiment was conducted with a coarse‐textured calcareous soil (pH‐H₂O 8.3) to study the effect of single and combined application of N and S fertilizers on soil pH, Fe, Mn, Zn, and P mobilization, and on growth and micronutrient uptake by com (Zea mays L.). Increasing amounts of elemental sulfur were mixed with the soil. To stimulate S oxidation, the treated soils were incubated for six weeks at field capacity. Nitrogen was applied as NH₄NO₃ (100, 200, and 400 mg N/kg). After six weeks, dry matter yields were recorded and shoots were analyzed for Fe, Mn, Zn, and P. At the end of the experiment, soil pH and the DTPA‐extractable micronutrients were determined. The results showed that: a. Soil pH was decreased by 0.2, 0.5, and 0.9 unit as a result of increasing S applications.

b. Applied sulfur and N fertilizer had increased the availability of micronutrients to following crops.

c. Application of N and/or S resulted in increased dry matter yields.

d. Manganese uptake tended to be higher as amounts of N applied increased; this was most evident at the higher S application rates. This effect was, however, reversed for Fe, Zn, and P uptake.

e. Under our experimental conditions, promising results were achieved on improving micronutrient availability and uptake when 400 mg N/kg was combined with 3 g S/kg.

     

Compositional nutrient diagnosis and main nutrient interactions in yellow pepper grown on desert calcareous soils

Mineral‐nutrient stress is one of the main factors limiting crop production, especially in arid lands. The mineral requirement of a crop is difficult to determine, and the interpretation of foliar chemistry composition is not easy. This study was conducted to compute the minimum yield target for fresh fruit of yellow pepper (Capsicum annuum L.) and the corresponding Compositional Nutrient Diagnosis (CND) as well as to identify significant nutrient interactions of this crop in desert calcareous soils. Preliminary CND norms were developed using a cumulative variance‐ratio function and the chi‐square distribution function. From a small database, we computed means and standard deviations of row‐centered log ratios, V_X, of five nutrients (N, P, K, Ca, and Mg) and a filling value, R, which comprises all nutrients not chemically analyzed and quantified them in 54 foliar samples of the popular yellow pepper cv. ‘Santa Fé’. This cultivar is widely grown in northwest Mexico under arid conditions. These norms are associated to fresh fruit yields higher than 15.04 t ha^–1. Principal‐component analyses, performed using estimated CND nutrient indexes, allowed us to identify four interactions: negative P‐Ca, P‐Mg, and N‐K, and positive Ca‐Mg. Pepper plants growing on calcareous soils tend to take up more Ca and Mg than considered as optimum in other soil conditions.     

Influence of mycorrhizal fungi on growth,chlorophyll content,and potassium and magnesium uptake in maize

Mycorrhizal fungi affect growth and nutrition of host plants positively. In this research, influence of vesicular-arbuscular mycorrhiza (VAM) ongrowth, chlorophyll content, and potassium (K) and magnesium (Mg) uptake in maize seedlings in pot culture was studied. This experiment was performed using natural soil containing a mixture of spores of Glomus spp. Mycorrhizal spores were exposed to four concentrations of K solution, i.e. 0.61 (soil K content), 0.92, and 1.23 meq/L and three concentrations of Mg, i.e. 4.8 (soil Mg content), 7.2, and 9.6 meq/L concurrently. Plants were watered every 4 days for 16 days with 50 mL distilled water. A pot with sterilized soil was used as negative control. For study of mycorrhizal colonization, very thin manually prepared longitudinal sections of plant roots (>1 mm in diameter) were stained with lactophenol-cottonblue and examined microscopically. Percentage of mycorrhizal colonization was determined using the grid-line intersect method. Samples from root and shoot of maize were collected for further analysis. Results showed mycorrhizal plants had significantly higher dry and fresh weight and chlorophyll content than plants grown in sterilized soil (p ≤ 0.05). Treatments with concentrations of 7.2 meq/L of magnesium alone and in combination with 0.92 meq/L of potassium with7.2 meq/L of Mg had better effect on morphological characters (dry and fresh weight of root and shoot). Mycorrhizal colonization increased Mg uptake but decreased K uptake.     

Phosphorus deficiency diagnosis and fertilization in mungbean grown in rainfed calcareous soils of Pakistan

Abstract

Mungbean [Vigna radiata (L). Wilczek] grown in rainfed calcareous soils suffers with phosphorus (P) deficiency. In view of high cost and low use efficiency of P fertilizer, greenhouse, incubation, and field experiments were carried out for determining P deficiency diagnostic criteria and efficient method of P fertilizer application in mungbean. In a pot culture experiment using a P‐deficient Typic Ustocherpt, maximum increase in grain yield with P was 686% over the control; and fertilizer requirement for near‐maximum (95%) grain yield was 30 mg P kg^‐1 soil where fertilizer was mixed with the whole soil volume (broadcast) and 14 mg P kg^‐1 where mixed with 1/4th soil volume (band placement). In a field experiment on a P‐deficient Typic Camborthid, however, maximum increase in grain yield was 262% over the control. Band placement resulted in 73% fertilizer saving as P requirement was 66 kg ha^‐1 by broadcast and only 18 kg ha^‐1 by band placement. Critical P concentration range appears to be 0.27–0.33% in young whole shoots (≤30 cm tall) and 0.25–0.30% in recently matured leaves. In an incubation study using the same Typic Ustochrept, P extracted by the sodium bicarbonate (NaHCO₃), the ammonium bicarbonate‐diethlylenetriaminepentaacetic acid (AB)‐DTPA), and the Mehlich 3 soil tests correlated closely with each other, P concentration of whole shoots, and total P uptake by mungbean plants. Critical soil test P levels for pot grown mungbean were NaHCO₃,9 mg kg^‐1; AB‐DTPA, 7 mg kg^‐1; and Mehlich 3, 23 mg dm^‐3 soil. The more efficient and economical ‘universal’ soil test, AB‐DTPA, is recommended for P fertility evaluation of calcareous soils.     

土壤中磷、钾、钙、镁的同时提取以及对巴西南部作物的钾肥推荐

Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and effciency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin methods for simultaneous extraction of soil available P, K, Ca, and Mg as well as the effect of using conversion equations on nutrient recommendations for crops. Topsoil (0-20 cm) samples were taken from the most representative soil types used for crop production in southern Brazil with a wide range of chemical, physical, and mineralogical properties. Soil P, K, Ca, and Mg were simultaneously extracted using 1.0 mol L-1 KCl, Mehlich-1 and Mehlich-3 solutions, and membrane resin. The amounts of P extracted with the Mehlich-1 method were, on average, 50% lower than those extracted with the resin and Mehlich-3 methods. However, the resin method extracted the lowest amounts of K, Ca, and Mg. The use of conversion equations was suitable and it did not a?ect negatively the K recommendations for crops grown on soils of southern Brazil.     

钾镁水平对番茄苗期生长、根系形态及钾素吸收和生理利用效率的影响

采用水培方法,研究不同钾、镁水平对"天福冠露"和"毛粉802"两种番茄幼苗生长、根系特征及钾素吸收、利用效率的影响。结果表明,钾、镁水平(8 mmol/L、1 mmol/L)处理的植株鲜重、干重及钾、镁水平(4 mmol/L、4 mmol/L)处理的株高显著高于其他处理。随钾、镁水平升高,两种番茄植株的根长、"天福冠露"植株的根直径、根体积和分根数先减少后增加;番茄植株钾素吸收率显著提高,生理利用效率显著降低。钾、镁水平(8 mmol/L、1 mmol/L)处理的植株根长、根表面积、根直径及根体积显著高于缺钾处理。钾、镁水平(4 mmol/L、4 mmol/L)处理,两种番茄植株根长、根表面积、根体积和分根数均显著高于缺镁处理,"天福冠露"植株钾含量显著高于"毛粉802",而钾素生理利用效率显著低于"毛粉802"。与其它等钾处理相比,缺镁植株钾素积累量最低、生理利用效率最高,镁过量处理的植株钾素生理利用效率显著降低。     

Kinetics of nonexchangeable‐potassium release and plant response in some calcareous soils

Nonexchangeable K⁺ constitutes a slowly available reserve that may significantly influence K⁺ fertility of soils. Laboratory and greenhouse experiments were conducted to characterize the K⁺ supply and nonexchangeable K⁺–release kinetics in 10 calcareous soils using 0.01 M CaCl₂ and 0.01 M oxalic acid extractions. Total K⁺ uptake by wheat (Triticum aestivum L.) grown in the greenhouse was used to measure plant‐available K⁺. The release of K⁺ was characterized by an initial fast rate followed by a slower rate. The nonlinear relationship in the early stages of the K⁺ release may be attributed to the edge sites, and release of K⁺ from interlayer exchange sites may be responsible for the second part of the K⁺ release. Kinetics of K⁺ release was described best with power function, which showed the best fit of the four models tested. Parameters of kinetics models in 0.01 M CaCl₂ were significantly related to K⁺ uptake by wheat. Potassium release was also correlated to initial NH₄OAc‐extratable K⁺ and to HNO₃‐extractable K⁺.     

营养型土壤改良剂对酸性土壤中钾的调节及玉米吸钾量的影响

营养型土壤改良剂(以下简称改良剂)施入三种不同肥力水平的土壤进行恒温培养试验和盆栽试验,测定土壤有效钾的含量、盆栽试验玉米的生物量和钾吸收量。结果表明:对于有效钾含量高的土壤,改良剂能促进钾的缓效化,有利于土壤钾的保蓄,防止土壤钾的淋失;对于有效钾含量较低的土壤,改良剂可以活化土壤中的钾,提高土壤钾的有效性;不同肥力水平的土壤,改良剂都能促进玉米对钾的吸收,有利于提高钾肥的吸收利用效率。     

镁、钾相互作用对水稻生长、养分吸收及有关生理特性的影响

在温室条件下,采用液体培养方法研究了Mg、K相互作用对水稻生长、养分吸收以及有关生理特性的影响。结果表明,在低Mg浓度条件下,水稻植株干物质积累随K浓度增加而减少;在高Mg条件下水稻植株干物质积累随K浓度增加而相应增加。在低Mg条件下,高浓度K显著抑制植株对Mg、K、N和P的吸收;在高Mg浓度下,植株对Mg、K、N和P的吸收有促进作用。植株叶片叶绿素含量在低Mg条件下随K浓度增加而减少,在高Mg条件下K浓度增加对叶绿素含量无显著影响。叶片硝酸还原酶活性和可溶性蛋白质含量随Mg浓度增加而增加,而K浓度增加对叶片硝酸还原酶活性和可溶性蛋白质含量无明显影响。高Mg条件下的叶片可溶性糖和淀粉含量明显高于低Mg处理,并随K浓度增加而提高。Mg、K营养拈抗作用主要表现在低Mg高K浓度条件下抑制Mg的吸收。     

Complexing of lead by DTPA in calcareous soils

Ten agricultural soils were spiked with 100 μg of Cu, Zn, and Pb g^?1 of soil. The complexation of Pb by 10^?4 M DTPA was determined after 60 days of metal equilibrium. A theoretical stability model of Fe, Mn, Cu, Zn, Ca, and Pb, between pH 1 and 10 was developed. It showed that CuL^3? (55.4 to 63%), CuHL^2? (0.1 to 9.4%), PbL^3? (29.1 to 33.3%), PbHL^2? (0.01 to 2.5%) and MnL^3? (2.8 to 3.2%) as the predominant species between pH 6 and 9. Other species like CaL^3?, CaHL^2?, FeL^2?, FeHL^?, FeL^3?, FeHL^2?, ZnL^3?, ZnHL^2? and MnHL^2? were less than 0.1% between pH 6 and 9. In the experimental soils, DTPA-Pb complexes accounted for 12.3 to 21.2% of metal complexed after 3 days of DTPA equilibriation. DTPA-Cu complexes were the major complexed species in the soils ranging between 72.5 and 82.2% after 3 days equilibriation with 10^?4 M DTPA. The proportion of Zn complexed by DTPA (3.8 to 10.1%) was much greater than predicted by the theoretical model. On the contrary, Mn was not complexed in appreciable amounts by DTPA.