ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00653.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.Recent progress in the techniques for improving the quality and quantity of herbage produced from indigenous hill pasture is described. There is general agreement on the main technical requirements for most situations. Knowledge of hill soils and vegetation and of the proposed grazing strategies for hill sheep are required initially so that the most economical and biologically appropriate method can be selected.In brief, soil pH must be raised by liming to at least 5.5; for each hectare, between 40–60 kg P and 80–100 kg K must be added plus a starter dressing of between 50–100 kg N after which a seeds mixture of grasses and white clover (25–30 kg seed ha−1) should be sown. Inoculation of clover seed with rhizobia is advised for all hill soil types but is essential for white clover sown in deep peat. Seeds must be sown in April or May, cultivation should be limited as far as possible for both technical and financial reasons, and new pastures should be grazed lightly initially, with subsequent rest periods to aid the persistence of white clover. Maintenance dressings of lime and fertilizer are required, more so in wetter areas. Careful monitoring of stock grazing recently improved hill pasture is advised to check for the occurrence of trace element problems.It is clear that the key to more efficient livestock rearing in the hills and uplands lies in pasture improvement and optimum utilization and maintenance of the upgraded

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00654.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.Two hill pastures in north Dyfed, Wales, were each treated at reseeding in 1971 with 2.25, 4.5 and 9.0 kg ha−1cobalt sulphate. Herbage samples for analysis of Co content were taken in summer at each site from 1971 to 1976 and also at site 1 from 1977 to 1983. Acetic acid extractable Co was measured in soil samples taken each winter for the same period at both sites. At site 1, on a peat, the treatments continued to give worthwhile increases in herbage and soil Co after 13 years. At site 2, on a mineral soil, the residual effects were small and lasted no more than four years. It is suggested that me lower response and residual value at site 2 is due to higher levels of exchangeable and easily reducible manganes

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00655.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.The bracken fern (Pteridium aquilinum(L.) Kuhn) is emerging as the most successful of international weeds. Tolerant, yet aggressive and opportunist, it follows characteristically in the wake of evacuated settlement, deforestation or reduced biotic pressures. It is hostile to many other plants and to animals, and generates toxins including some carcinogens. It appears to be extending its range into wet and exposed habitats and at its climatic limits. Estimated encroachment rates in the UK average 1%, sometimes 3% per annum, which appears to be unprecedented. Its historical use as an occasional resource, e.g. for litter, bedding, roofing, etc, has mostly ceased. It is now a major source of land loss and land pollution. More work is needed (and is pending) to calibrate bracken spread more precisely, e.g. from satellite imagery. The reclamation of bracken‐infested land is probably more cost‐beneficial per hectare than the reclamation of wetland or heathland, taking any time‐

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00656.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.The reasons for bracken encroachment in Scottish hill land are examined. The cost effectiveness of bracken control methods are discussed and it is shown how the real cost of aerial spraying, the most practical method, has increased in the last decade. The waiving of the follow‐up requirements under the DAFS grant schemes may alter this cost situation in the future. The need for more accurate estimates of the extent of the bracken problem is highlighted by the possible link between bracken and cancer in humans. Recent surveys utilizing remote sensing techniques are described and the cost of a full bracken eradication programme is estimated to bec.£80 million which is contrasted with the current level of grant assistance ofc.£135 000 a−1. The use of bracken as biofuel is considered as an alternative to eradic

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00657.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.The approximate time‐scales for serious lowering of the base status of acidic upland soils in northeast Scotland have been based on assessments of geochemical weathering rates in two upland catchments. Periods of 1100 and 12000 years are obtained for soils evolved primarily from granite and quartz‐biotite‐norite respectively. Factors regulating the rate of removal of base cations in drainage water are discussed, to elucidate those which significantly influence long‐term rates of soil acidification. The relationship between base cation leaching and river water acidity is briefly con

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00658.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.Correlation analysis was used to determine the main factors related to soil pH and to yield of white clover in a range of hill soils. Results for 109 Northern Ireland pasture soils showed that pH (H2O) was significantly correlated with exchangeable Ca, total exchangeable bases, base saturation, P, exchangeable Al and Al saturation, but not with exchangeable Mn. Clover yield (dry weight of shoots) in 12 acid soils from Northern Ireland, Scotland and the Falkland Islands was significantly correlated with exchangeable Ca, total exchangeable bases and Al saturation. The results support the use of Al saturation rather than exchangeable Al, soil solution Al or pH when calculating lime requirements to overcome these limiting factors in hill soils.

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00659.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.Plaster of Paris (CaSO4½H2O) infiltration was used (i) to study the continuity of cracks and pores and the variation of macroporosity and crack width with depth and (ii) to maintain an undisturbed seedbed for subsequent resin impregnation. Examples are also given in which the remains of gaps between and at the bottom of the furrow slice can be clearly seen. The method is a useful qualitative visual technique, limited to the larger soil pores. Due to this limitation, it is more useful for showing pore continuity than for quantifying porosity

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1985.tb00660.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY