摘要:

SummarySoils with paleosol features occur at the surface on the Chalky Boulder Clay in the Chelmsford area, Essex. Their particle size distribution, micromorphology and sand, silt and clay mineralogy indicate periods of weathering, clay illuviation and hydromorphism before deposition of loess in the Late Devensian. These periods are provisionally related to the Ipswichian and/or Hoxnian Interglacials.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00970.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryThe spatial pattern of sodium in soils was investigated in a catenary sequence in central Rhodesia. Sodic horizons occurred predominantly in mid‐slope and are related to (a) fluctuations in water table, (b) poor lateral drainage and a perched water table and (c) the weathering rate of feldspars. Observations suggest that a subsurface dam wall is responsible for lack of groundwater drainage and that this impediment to lateral drainage is caused primarily by excess sodium and the dispersion of clays. Near‐surface fluctuations of the water table encourage weathering and increase the sodium concentrations. The existence of a perched water table and readily dispersibte soil may have important implications in erosion, explaining why sodium‐rich soils are often associated with severe erosional phenomena especially in tropical and subtropical environ

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00971.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryThis paper describes the accumulation of uranium in soils from superphosphate applied annually to arable and grassland soils. Rates of application of superphosphate were equivalent to about 33kg P and 15 gU ha−1year−1in three experiments at Rothamsted and to about 37 kg P and 16g U ha−1year−1in one experiment in New Zealand. Most of the uranium (about 1300 g U ha−1) applied in superphosphate to the clay loam soil at Rothamsted since 1889 was retained, like P, in the plough layer of arable soils or was adsorbed by the organic surface layers of soils under permanent grassland. Uranium applied in superphosphate to grassland in New Zealand since 1954 (about 330 g U ha−1) was also concentrated in the surface layers

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00972.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryBenlate (50 per cent wettable powder), the commercial formulation of the systemic fungicide benomyl, was applied to a flooded alluvial soil at concentrations of 5 to 100 μg/g active ingredient. At about the field application rate (S μg/g), benomyl retarded the decrease in the redox potentials of the flooded soil and curtailed the accumulation of iron and manganese in solution, both without and with added rice straw (0.5 per cent

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00973.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryAnalysis of displaced soil solutions, at half available moisture percentage, indicated that Mg to Ca (Mg/Ca) ratios and Ca to total cation (Ca/TC) ratios ranged from 0.35 to 3.64 and 0.74 to 0.04, respectively, in the A and B horizons of the solonetzic soils under study. The growth of barley in simulated solution cultures commenced to decline when the Mg/Ca ratio in solution exceeded 1.0, or when the Ca/TC ratio was lower than 0.15, regardless of levels of salinity, concentrations of Ca or Mg, or differences in ionic strength. Reduced growth was followed by symptoms of Ca deficiency. Growth of barley in soil from various horizons of solonetzic soils supported the results found in solution culture. Calcium amendments to soils with low Ca/TC ratios or high Mg/Ca ratios in the soil solution, gave increases in growth and prevented Ca deficiency.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00974.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

SummaryExtractions of Fe(III) and Al(III) from hydrolyscd metal polymers, hydrous metal oxides, kaolinite, metal humates and soil were made using acetyl acetone in both polar and non‐polar solvents. Amounts of metal ions removed from inorganic materials were similar in both solvents, but from metal humates and soil more metal ions were removed in the aqueous system. The hydration state of the organic material was considered responsible for the difference. The results demonstrate that caution should be taken in ascribing metals extracted by selective dissolution techniques to particular soil components when non‐polar solvents are u

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00975.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00976.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1979.tb00977.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY