摘要:

The purpose of this study was to determine whether green manure used either in rotation or intercropped with corn could increase soil organic-matter levels and improve soil physical conditions. Eight treatments were applied for a 3-year period to a Bearbrook clay and a Franklin gravelly loamy sand in a rotation experiment. Aggregate-size distribution, bulk density, moisture retention, and water flow were measured for each soil.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755112

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The effects of several organic and mineral fertiliser manurial regimes were compared on undisturbed and former opencast grassland. Earthworm casting, burrowing, and population data were recorded on two field trials over a number of years. Treatment responses were similar on opencast and undisturbed land. Topdressed poultry manure encouraged casting and burrowing to the surface. In contrast, NPK fertiliser discouraged these activities, the reduction in casting becoming larger at higher rates of application. Responses to urea were less consistent; alone, its effect was negative, but, whereas NPK fertiliser interacted negatively with manure, urea produced a positive interaction effect.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755113

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Fungi were isolated from diseased and decaying water hyacinth,Eichhornia crassipes(Mart.) Solms-Laub. from twenty three sites in eastern Australia. Some of the fungi had not previously been recorded on this host, but the majority were species known on water hyacinth in America and Asia, including pathogensAcremonium zonatum(Sawada) Gams andCercospora piaropiTharp. Bacteria isolated werePseudomonas fluorescensand a non-fluorescent pseudomonad unlike any published species description. A greater variety of fungi occurred on plants damaged by the insect biological control agents,Neochetina eichhorniaeWarner andSameodes albiguttalis(Warren) than on plants not attacked by these insects. Many of the species are ubiquitous on decaying plant material. No particular fungus could be recognised as the main cause of necrosis which is associated with damage by insect larvae to the petiole and rhizome, but microorganisms are considered to be important in achieving the overall biological control. In contrast to other infections of the lamina, the lethal effect of a leaf blight was linked to severe infection of the lamina of the younger leaves. In glasshouse pathogenicity tests,Fusarium spp., A. zonatumandC. piaropicaused more disease than any other microorganism tested.A. zonatumandC. piaropiare considered to have the greatest potential for development as mycoherbicides.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755114

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In an incubation study the comparative effects of different carbonaceous compounds on the immobilization and mineralization of phosphorus applied to the soil were investigated. Approximately 31.7% and 29.5% of added P in soils containing additions of glucose and starch was converted into organic P within 10 and 20 days of incubation respectively. Most of this converted organic P was found in the form of labile and moderately labile forms of organic P and both of these readily mineralized again leaving less than the native labile P fraction of the control treatment. In the case of cellulose and crude fibre additions, the immobilization started slowly and reached a maximum of 31.9% and 27.9% of applied P at 40 and 50 days of incubation respectively. More than 63% of the increased organic P was contributed by fulvic and humic P fractions which showed resistance to mineralization. Lignin did not show any significant effect on immobilization and mineralization of P in the soil. Cellulose, per gram of its carbon decomposition, had a higher capacity for immobilization than the other sources of carbonaceous compounds.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755115

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Soil erosion is a world-wide phenomenon having a serious effect upon many agricultural soils. Until recently it was considered that erosion in Britain was limited to only a few susceptible soils in specific areas. However, the increasing monitoring of soils over the past 20 years has shown that water induced erosion is now a widespread and growing threat to farmland in many parts of Britain. This increase in the incidence of erosion can be directly related to changes that have taken place in agricultural practise in recent decades, with traditional mixed farming systems based on complex rotations being replaced by increasingly intensive and specialised cropping systems.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755116

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755117

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755118

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755119

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755120

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755111

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor