摘要:

Endive (Chicorium endiviaL.), a crop tolerant of acid soil conditions, was grown in a loamy sand, a loam, and a silt loam in a greenhouse. The soils were treated with limestone and a high‐calcium sewage sludge and with five levels of Zn ranging from 0 to 800 mg.kg‐1. Limed soils were about pH 6 ‐ 6.5 compared to pH 4.5 ‐ 5 for unlimed soils. Zinc concentrations in shoots of endive grown in limed soils were less than those in unlimed soils. Sludge increased Zn concentrations in plants grown in the loam or silt loam but not in the loamy sand. The pH of the loamy sand was increased by the addition of sludge and may have limited Zn entry into the plants. A second addition of sludge enhanced Zn levels in plants, and the effects of the sludge appeared to be related to the resultant soil pH.

ISSN:0010-3624    

DOI:10.1080/00103628909368065

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Effect of two moisture levels (22.5 and 13.5%, w/w) and wetting‐drying cycles on manganese solubility was studied in NaCl‐amended soil. During 6 d incubation, higher moisture level released 40‐fold more water‐soluble Mn and 60‐fold more NH4OAc‐exchangeable‐Mn in non‐salinized soil. In NaCl‐treated soil, 50 to over 200% greater soluble and exchangeable Mn was recovered from samples incubated at 22.5% compared to 13.5% water levels. Wetting‐drying cycles significantly (P≤0.05) decreased water‐soluble Mn, which accounted for 50 to 60% increases in the exchange‐able Mn. Since other non‐oxidizing/reducing cations (Ca, Mg, Na, K) also demonstrated similar behavior, it is proposed that in addition to oxidation upon drying and reduction upon wetting, the increases in exchangeable Mn and simultaneous decreases in soluble Mn concentration are due to sorption processes. These results suggest that under field conditions, the insolubility of Mn due to continued wetting‐drying cycles may eventually lead to Mn deficiency in soils low in Mn.

ISSN:0010-3624    

DOI:10.1080/00103628909368066

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A laser light scattering technique was assessed for measuring the microaggregate size distribution (MSD) of three Italian soils after water dispersion and after disaggregation with ultrasound. MSD values were unaffected by the amount of sample in the dry weight range from 0.05 to 2.0 grams. Some disaggregation of water‐treated samples may occur in the measuring system, so an appropriate measurement time has to be selected.

ISSN:0010-3624    

DOI:10.1080/00103628909368067

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Molybdenum (Mo) extracted from 31 New Zealand soils by an anion exchange resin method (resin Mo) was compared with that extracted by Tamm's oxalate (oxalate Mo). The amounts extracted by the two methods were correlated but, on average, oxalate Mo was 7 times resin Mo. Resin Mo was correlated with relative yield and Mo uptake of lucerne, although correlations were not high. Oxalate Mo was not correlated with plant data. Inclusion of pH in multiple regressions improved correlations with relative yield for both methods but the prediction equations accounted for only 30–35% of the variation. It is concluded that the resin method, although better than the oxalate method, is not sufficiently accurate for diagnosis of Mo deficiency’ in New Zealand pastoral soils.

ISSN:0010-3624    

DOI:10.1080/00103628909368068

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

An incubation experiment was performed to study the effects of vegetation water on S transformation in a calcareous soil. In addition to raw vegetation water, other preparations were tested including vegetation water devoid of organic matter and deionized vegetation water. The addition of olive wastewater to soil inhibits the formation of S‐SO4=when vegetation water plus elemental S is compared to a treatment consisting of elemental S applied alone. No such effect, however, was seen when the treatment with vegetation water only is compared with control sails. Of the three types of vegetation water tested, the least effective inhibitor of S‐SO4=formation was the wastewater in which all organic matter has been eliminated, while the deionized effluent yielded lowest levels of S‐SO4=. The exclusive application of vegetation water on calcareous soils may raise S‐SO4=levels in the middle run; however when an S deficient soil is fertilized with elemental S, concurrent application of vegetation water is unadvisable, given that it may interfere with soil. S‐SO4=formation.

ISSN:0010-3624    

DOI:10.1080/00103628909368069

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The concentrations of volatile fatty acids (VFA) in soils are important in studies involving phytotoxicity and fermentation processes. Concentrations of acetic, propionic, and butyric acids as low as 0.21, 0.14, and 0.10 mmol kg‐1soil in water extracts were accurately determined. The extracts were filtered through 45 μm millipore disc filters and injected directly into a gas chromatograph following addition of purified formic acid. The formic acid eliminated ghosting of peaks. The gas chromatograph was equipped with a flame ionization detector and a 60/80 Carbopack C/0.3% Carbowax 20M/0.1% H3PO4packed precolumn (0.15 m) and column (1.83 m). The precolumn was changed after 150 to 200 sample injections when contaminated beyond acceptable limits. There was good separation of VFA with no interfering organic volatiles in extracts of soil containing glucose, cellulose or straw incubated anaerobically for as long as 4 weeks. The advantages of the procedure are relative rapidity and simplicity as well as improved sensitivity in measuring small quantities of volatile fatty acids in soil

ISSN:0010-3624    

DOI:10.1080/00103628909368070

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The pretreatment of soils with pH5 sodium acetate (NaOAc) buffer is widely used to remove carbonates from soils prior to dispersion and separation of clays for mineralogical analysis. The effect of this pretreatment on other minerals such as palygorskite and zeolite (analcime) was evaluated. Soil samples from Arizona and Egypt as well as reference samples of palygorskite and analcime spiked with CaCO3were used. The pretreatment of the soils and reference samples had no observable change in the mineralogy as indicated by X‐ray diffraction and SEM analysis. The study further suggests that the somewhat tedious and time consuming step can be avoided for the mineralogical analysis of many arid land soils.

ISSN:0010-3624    

DOI:10.1080/00103628909368071

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A simple and accurate ion chromatography method for the determination of nitrate in 2,0 M KC1 soil extracts is described. The method can be carried out on a commercially available chromatograph using a reverse phase column with tetrabutylammonium hydrogen sulphate as the mobile phase. Ultraviolet absorbance at 220 nm was used to quantify the nitrate. Statistical analyses showed that nitrate values obtained for 30 soils by this chromatographic method agree closely with those obtained by a colorimetric method. A notable advantage of this method is the direct determination of nitrate by ion chromatography in the most commonly used extractant

ISSN:0010-3624    

DOI:10.1080/00103628909368072

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The objective of this study was to examine the effects of weighing and scooping soil samples on the accuracy of soil test results, fertilizer and lime requirement recommendations using the metric, British and American measurement systems. Although, it is well Known that BO values of mineral soils vary easily by 100Z (values vary by as much as 1000% when including Histosols) from an average assumed value, one of the most widely held delusion in North American soil testing circles is that a defined constant weight of soil can be measured volumetrically. Analytical results can only be extrapolated accurately to a furrow layer of defined weight when samples are weighed for analysis. Analytical results ought then be reported as ppm, μg gram‐1, or mg kg‐1soil. Unfortunately a furrow layer of defined weight is likely to have an undefined depth. Several scoop sizes are being used to measure an assumed weight of soil, it is suggested that laboratories following this practice report analytical results in pounds acre‐1or kg ha‐1, but also display their assumed soil density (ASD) to facilitate analytical comparisons and eventual standardization. Ultimately, erroneous assumptions can be avoided by defining the acre and hectare furrow layers as being volumes having depths of 20 cm and containing 0.81 and 2‐million liters of soil, respectively. Plant nutrient concentrations of 1 μg in 0.89 or 1.0 mL soil then represent two pounds acre‐1or two kilograms ha‐1, respectively. Reporting analytical results in pg mL‐1soil is suggested as the correct form for those that have adopted the metric system. Procedures are developed to convert LR values from furrow weight to furrow volume, for the American, British, and metric system of measurements

ISSN:0010-3624    

DOI:10.1080/00103628909368073

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Extracting sludge‐amended soil with DTPA does not always give a reliable measure of plant‐available heavy metals. The major purpose of this greenhouse pot study was to help explain why. Two anaerobically digested sludges from sewages treated with either Ca(OH)2or FeCl3were applied to 3‐kg samples of a Mollic Albaqualf previously limed with Ca(OH)2rates of 0, 2.5, and 10g/pot that resulted in pHs in the check pots of 5.4, 6.2, or 7.7 after the first harvest. Sludge rates provided 0, 200, 40, 800, and 1600 mg Zn kg‐1of soil. Two consecutive crops of soybeans (Glycine MaxL.) were grown for 42 d each in the greenhouse. DTPA‐extractable, soil‐solution, and plant concentrations of Cu2+, Ni2+, and Zn2+were measured.

ISSN:0010-3624    

DOI:10.1080/00103628909368074

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor