摘要:

Possible sources of errors in the determination of boron in plant samples were examined. This paper will first describe some general features and then the following steps in the pre‐treatment of plant samples:a.Dryingb.Grindingc.Dry ashing, effects of temperature, time and additivesd.Wet ashing, loss of boron when using different acids, boron contamination from glassware and other related aspectse.Extraction of plant samples

ISSN:0010-3624    

DOI:10.1080/00103628609367693

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Soil acidity is a major factor responsible for reduced alfalfa (Medicago sativaL.) yields in humid regions of the United States. The purpose of this study was to investigate the effect of Ca, Al, and pH interactions on alfalfa growth. Two experiments were conducted in modified plastic growth pouches. Experiment 1 studied the influence of pH (4.5 and 6.5) at varying levels of Al (0.00, 0.08, 0.15 mM) with 1 mM Ca, while experiment 2 studied the interaction between Ca (0.00, 0.30, 1.00, 3.00, 6.00 mM) and Al (0.00, 0.08, 0.15, 0.30 mM) at pH 4.5 on alfalfa shoot and root development. In the absence of Al, root and shoot growth were not affected by a pH of 4.5 as compared to a pH of 6.5. Increasing Al from 0.00 to 0.30 mM caused a reduction in both shoot and root growth at pH 4.5 when Ca was less than 3.00 mM. In the presence of 0.08 mM Al, additional Ca at 3.00 and 6.00 mM increased shoot growth equal to that of the 0.00 Al treatment. The optimum level of Ca for root development was at least 1.00 mM in the absence of Al; however, in the presence of 0.08 mM Al, additional Ca (≥3.00 mM) reduced Al toxic effects. Increasing levels of Ca (0.00 to 6.00 mM) decreased Al in roots from 9.4 to 4.7 g kg‐1in treatments containing 0.30 mM Al. Additional Ca (≥3.00 mM) in the pH 4.5 nutrient solution was beneficial for shoot and root growth in the presence of 0.08 mM Al and a pH of 4.5 was not detrimental to alfalfa seedling growth unless at least 0.08 mM Al was present.

ISSN:0010-3624    

DOI:10.1080/00103628609367694

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Blocks were formed from peat or peat‐lite amended with a granulated hydrophilic polymer (Viterra Agri‐gel®, potassium propenoate‐propenamide copolymer) or a binding agent (Natrosol 250 HHR®, hydroxyethyl cellulose). Blocks were subjected to slow‐release (Osmocote®) or solution fertilization and to cyclical or capillary irrigation. Tomato seedling shoot fresh weight was acceptable in peat‐lite blocks irrespective of fertilization or irrigation regime, and in peat blocks irrespective of irrigation regime if provided solution fertilization. Shoot fresh weight increased quadratically with increasing Agri‐gel incorporation rate in peat and peat‐lite blocks receiving solution fertilization, irrespective of irrigation regime. Peat blocks held more water and underwent less expansion with hydra‐tion than peat‐lite blocks. Capillary irrigation resulted in greater block stability than cyclical irrigation. Agri‐gel incorporation in blocks increased block water content and block stability. Natrosol incorporation further enhanced block stability but generally had no effect on tomato shoot growth.

ISSN:0010-3624    

DOI:10.1080/00103628609367695

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effects of 14 urease inhibitors on denitrification of nitrate in soil were studied by determining the effects of 1, 10, and 50 μg g‐1soil of each inhibitor on the amounts of nitrate lost and the amounts of nitrite, N2O, and N2produced when samples of soil were incubated anaerobically after treatment with nitrate or with nitrate and mannitol. The inhibitors used were catechol, hydroquinone, 1,4‐benzoquinone, 2,5‐dichloro‐l,4‐benzoquinone, 2,6‐dichloro‐l,4‐benzoquinone, 2,5‐dimethyl‐l,4‐benzoquinone, 2,6‐dimethyl‐1,4‐benzoquinone, sodium‐4‐chloromercuribenzoate, phenylphosphorodiamidate, phosphoric triamide, N‐phenylphosphoric triamide, N‐(diaminophosphinyl)benzeneacetamide, N‐(diamino‐phosphinyl)benzamide, and 4‐fluoro‐N‐(diaminophosphinyl)benzamide.

ISSN:0010-3624    

DOI:10.1080/00103628609367696

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Calcium silicate slag is a by‐product of the electric furnace reduction process for producing phosphoric acid from phosphate rock (PR). Since slag contains trace amounts of radium (Ra), and uranium (U) as contaminants from the PR, a greenhouse pot experiment was conducted to determine if plants absorb Ra from slag applied to soil. Slag at rates equivalent to 0 and 22 mt/ha was mixed with Mountview silt loam (Typic Paleudults) limed to pH 5.8 and 7.2. Three clippings each of fescue (Festuca arundinaceaSchreb.), and Swiss chard (Beta vulgarisL.), and one harvest of wheat (Triticum aestivumL.) for grain and straw were grown on separate series of treated soil, and plant samples were analyzed for radioactivity due to Ra uptake. Samples of sugarcane (Saccharum officinarumL.) forage and extracted juice from field experiments in Florida testing this slag as a Si source also were analyzed for radioactivity.

ISSN:0010-3624    

DOI:10.1080/00103628609367697

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Oats (Avena sativaL. cv. Garry) were grown in microplots of three organic soils at site A (peat), site B (muck) and site C (mucky peat) in the summer of 1983. The soil surface (0 to 20 cm) varied in total Cu from 13 to 1659, 135 to 1745, and 81 to 1063 μg/g at sites A, B and C, respectively, due to applications of CuSO4.5H2O made at three rates in 1978, at sites A and B, and in 1979 at site C. Neither the rates of Cu application nor total soil Cu influenced yields. High levels of residual Cu increased the levels of Cu in straw at sites A and B, and in grain at site C. However, even the highest levels of Cu in straw and grains, were below the 20 μg/g which is often considered to be the threshold of Cu phytotoxicity. Data on the levels of other nutrients (P, K, Ca, Mg, Fe, Mn, Zn, B, Mo and S) in the tops and roots of oats generally revealed no significantly adverse effects of the Cu applications or total accumulated Cu in the three soils.

ISSN:0010-3624    

DOI:10.1080/00103628609367698

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In the last 40 years, Al has been proved to play a major role in the low fertility of acid soils, and a number of methods have been developed for its determination. In this paper, the performances of a titrimetric, an atomic absorption and a colorimetric method for the determination of Al in 0.6 N BaCl2extracts of five hill soils of the humid NW Spain are compared. Two of the soils were developed on granite, one on shale, one on schist and one on gabbro and their Al content ranged between 1.3 and 3.6 cmol(+)/L.

ISSN:0010-3624    

DOI:10.1080/00103628609367699

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The technique of simultaneous quantitative determination of mineral N soil forms (nitrates, exchangeable and non‐exchangeable ammonium, and total amount of these compounds) and sample pretreatment for the analysis of15N:14N ratio is suggested. The technique is based on the selective association of NH4+‐ions into indophenol complex and subsequent ethyl‐acetate extraction of this complex from solution. The mineralization of indophenol is carried out in alkaline medium with simultaneous NH3distillation into H2SO4titrant. The application of given technique allows us to shorten significantly the time required for analysis and to increase the accuracy of analytical determination.

ISSN:0010-3624    

DOI:10.1080/00103628609367700

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628609367692

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor