摘要:

The sorption of several organic phosphates were measured on soil, peat and other organic and inorganic materials. The behavior of the phosphates on these materials differed from that reported for similar studies on acidic soil materials. In contrast to the sorption on acidic soils, where sorption maxima occur, the sorption on basic soils may reach a maximum but does not decline thereafter. Both clay and organic matter content govern the amount of sorption but calcium seems to account for the differences observed from those on acidic soil materials

ISSN:0010-3624    

DOI:10.1080/00103628909368112

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Nine different types of plant material labeled with14CO2were used to compare two methods for analyzing14C in biological material. The methods were total carbon by wet oxidation (TC) and tissue solubilization using hyamine hydroxide (HH). In addition 3 sizes of material were used and 3 variations of the HH method were evaluated. Overall there were no significant differences between the HH and TC methods for14C activity, provided the samples are finely ground. Significant differences occurred in total counts and counting efficiency when the plant particle size decreased from .84 mm to .25 ram. Differences also were found between quench reducing treatments in the HH method. Differences between methods in terms of total counts, may be plant material specific

ISSN:0010-3624    

DOI:10.1080/00103628909368113

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Various grades and batches of filter papers were tested for their levels of inorganic nitrogen contamination (measured as ammonium, nitrate and nitrite‐N) by eluting them with 50 mL of 0.5 M potassium sulphate. Significant amounts of ammonium‐N were eluted from all the filter papers, however, most were low in nitrate and nitrite nitrogen. The amounts of ammonium‐N varied with the batch number, among boxes within a batch number and within filter papers from the same box. To minimise the effects of ammonium‐N contained in the filter papers, it is necessary to wash them with a salt solution, such as 0.5 M potassium sulphate, rinse them with deionized water and dry them prior to use

ISSN:0010-3624    

DOI:10.1080/00103628909368114

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Many methods have been proposed to determine the total amount of organic carbon in soil; some of them determine only a percentage of the actual carbon content and therefore the results need the application of a correction factor. Methods for the determination of organic carbon in soil have been rarely extended to organic fertilizers and amendments.

ISSN:0010-3624    

DOI:10.1080/00103628909368115

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A laboratory study was conducted to assess the effectiveness of phenylphosphorodiamidate (PPD) and N‐(n‐butyl) thiophosphoric triamide (NBT) in retarding urea hydrolysis in four flooded rice soils under simulated oxidized and reduced conditions. Urea (400 μg N g‐1soil) with PPD or NBT (2.0% w/w) was added to preincubated soils and analyzed for urea content 1, 3, 5, 7 and 15 days after N application. N‐(n‐butyl) thiophosphoric triamide was more effective in delaying urea hydrolysis under oxidizing conditions and at 5 days 57% of the added urea remained in the oxidized soils compared to only 4% under reduced soil conditions. In three soils, PPD was observed to be effective under reducing soil constraints. At 5 days 56 and 31% of the added urea was unhydrolyzed under reducing and oxidizing soil conditions, respectively, with the addition of PPD. For two soils 48% of the added urea remained at the 15 day sampling for the urea + NBT treatment

ISSN:0010-3624    

DOI:10.1080/00103628909368116

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Two properties that are detrimental to agronomic production with acid tropical soils are elevated aluminum concentrations and low phosphate availability. Direct application of carbonate apatites to acid tropical soils possessing low buffering capacity could possibly resolve this problem. The property that determines the effectiveness of directly‐applied carbonate apatites is the CO3/PO4ratio, which indicates the degree of anionic isomorphic substitution occurring within the mineral crystal lattice. Increasing ratios denote greater mineral solubility under acid‐soil conditions. Research was conducted to determine: a) fertilizer efficiency of three carbonate apatites (from North Carolina (NCPR), Central Florida (CFPR), and Kodjari, Upper Volta (KPR)), varying in CO3/PO4ratios, to that of triple superphosphate (TSP), and b) liming effects induced by the liberation of carbonates from each source, compared to CaCO3. Maize (Zea mays L.) was grown in pots containing 3 kg of a Dothan fine sandy loam (fine, loamy siliceous, thermic, Typic Paleudult). Yield was lower from carbonate apatite sources than from TSP during the first cropping period, but was equal to TSP treatments for the second cropping period with rocks possessing a CO3/PO4ratio greater than 0.14. The liming effect induced by liberation of carbonates and phosphates from NCPR (400 mg P kg‐1or 306 mg CO3kg‐1) equaled that from CaCO3(600 mg CO3kg‐1) during the first cropping period. Over experimental duration, the soil pH was increased by 0.60, 1.26, and 1.10 pH units with a resulting decrease of 0.13, 0.17, and 0.14 cmol(+) extractable Al kg‐1by CaCO3(600 mg CO3kg‐1), NCPR (306 mg CO3kg‐1), and CFPR (171 mg CO3kg‐1), respectively

ISSN:0010-3624    

DOI:10.1080/00103628909368117

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Acid oxalate reagent was used at various concentrations, pH values, shaking times, and soil to solution ratios to find the optimum conditions for the extraction of Al, Fe, and Si from short‐range‐order materials in soils and stream‐bed deposits. The optimum conditions vary with the nature of the soil sample and its components. For most soils maximum amounts of Al, Fe, and Si were extracted with 0.15M acid oxalate reagent at pH 3.0 with a soil to solution ratio of 1:100 and shaking for 4 h in the dark at 20°C. Soils with more than 5% oxalate‐extractable Al or Fe require a 0.20M oxalate solution at pH 3.0 with a soil to solution ratio of 1:200.

ISSN:0010-3624    

DOI:10.1080/00103628909368118

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The ion holding capacity, and strength and persistency of the ion holding phenomena of the materials were investigated through a simple and rapid method, by using Fraction Collector system. The materials were tested under Na‐Ca competing condition. Of materials used, farm manure held about 4/5 of the added ions, of which 48% were strongly held. The ion releasing pattern of the materials was influenced by their chemical and biophysical properties

ISSN:0010-3624    

DOI:10.1080/00103628909368119

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A field study was initiated on a Davidson sandy clay loam, clayey, kaolinitic, thermic Rhodic Paleudult soil in central Georgia in 1982 to evaluate P response of high‐ and low‐tannin sericea lespedeza (Lespedeza cuneata(Dumont) G. Don) cultivars. Following application of 0, 35, 70 or 105 kg ha‐1P, soil test values at the 0–15 cm depth ranged from 10.0 mg kg‐1in the control plots to 42 mg kg‐1at the 105 kg ha‐1P application rate.

ISSN:0010-3624    

DOI:10.1080/00103628909368120

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Recent development of the Cylindrical Internal Reflectance (CIR) sample cell has made infrared analysis of solutes in highly infrared‐absorbing solvents such as water possible. Fourier Transform Infrared spectroscopy (FT‐IR) has been combined with a CIR sample cell to determine the spectra of Aldrich humic acid in water at concentrations as low as 0.5 g L‐1. Spectral scans from 670 to .4000 cm‐1indicate that the region of greatest resolution for observing characteristic humic acid absorbance bands occurs from 1000 to 2000 cm‐1. Comparison of CIR spectra with Nujol mull and KBr spectra demonstrated a near total elimination of absorbance peaks from 1000 to 1200 cm‐1in the nonaqueous preparations. Solution phase parameters were altered to illustrate that the spectra of Aldrich humic acid in water varied with humic acid concentration, ionic strength, and pH. The ability to determine infrared spectra of humic materials in their native wet state will prove advantageous in determining humic material interaction with inorganic and organic pollutants such as trace elements and pesticides

ISSN:0010-3624    

DOI:10.1080/00103628909368121

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor