摘要:

Abstract.The soil conditions both before and after restoring opencast sites and their effect on drainage and crop growth are discussed both in general and with specific reference to the site concerned. Both drainage treatments showed a benefit over the undrained control, although no extra benefit was observed from drains at 20‐m spacing with mole drains and subsoiling compared to drains at 40‐m spacing with mole drains. Subsoiling reduced bulk density and increased surface infiltration rates, but improvements to the soil brought about by subsoiling were short‐

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Comparisons of crop production on recently reinstated soil in Northumberland have shown that the reduced yield potential of such soil may not be inevitable. Storage of soil in bunds did not greatly reduce subsequent crop yields, but failure to drain the land did. Provided an effective drainage scheme was installed, arable and grass crops could be grown successfully, responding very well to additions of nitrogen fertilizer and other normal good husbandry practices. To date it seems that neither deep cultivation nor the use of grass leys were as effective in the restoration process as had been expected.

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.A number of restored areas, a soil store and undisturbed areas on opencast coal mine sites, all of similar soil type, were sampled. The microbiological activity (dehydrogenase assay), nitrogen mineralization and nitrifying potentials and physico‐chemical characteristics of the soils were determined. Dehydrogenase activities ranged from 140 to 580 μg TPF g‐124 h‐1in undisturbed control soils, whereas the disturbed soils had activities of 10 to 220 μg g‐124 h‐1, with the smallest activities being recorded in the stored and most recently reinstated soil, indicating that disturbance has depressed microbial activity. Nitrogen mineralization potential was significantly affected by disturbance, with a value of 18 to 26 μg inorganic N g‐121 d‐1in the soil store and 38 μg‐121 d‐1in a soil reinstated for six months, although the values were less than this in soils reinstated for up to six years. Nitrifying potential was not significantly less in the stored soils, being within the range of 60 to 135 μg nitrate N formed g‐1soil 21 d‐1, which was similar to that found in the undisturbed control soil.The water‐holding capacity was less in the stored soil than the undisturbed controls, and was significantly less in soil reinstated for 1.5 to 2.5 years, being only 65% of the undisturbed value (0.66 g water g‐1soil). Ammonium content of the soil store was one hundred fold larger in the soil store than in the controls (0.6 to 1.7 μg ammonium N g‐1). The carbon contents in the control soils ranged from 4.5 to 7.2%, whereas the stored and reinstated soils had generally less amounts ranging from 1.6 to 5.8%. There was a significant and positive correlation between water‐holding capacity and nitrifying potential.The implications for

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Experiments on the effects of stockpiling soil on an opencast coal mine in Derbyshire showed that there were significant changes in the microbial community. Numbers of aerobic bacteria in stored soils ranged from 0.5 to 12.8 ± 107colony‐forming‐units (CFU)g‐1with the smallest values being in the deepest parts of the oldest stores, whereas an adjacent undisturbed soil contained 6.6 ± 107CFU g‐1. There was a greater effect on the numbers of fungal spores, which ranged from 0.1 to 6.7 ± 105CFU g‐1soil, all less than the 10 ± 105CFU g‐1recorded for the undisturbed control soil. The number of fungal spores in the deepest part of the older soil stores was only 1/100 of the number in the undisturbed soil. This was mirrored by the biomass values, as determined by adenosine triphosphate (ATP) assay. Values of ATP ranged from 0.38 to 13.13 nmol g‐1as compared to 5.8 nmol g‐1in the undisturbed soil. All three of these microbiological properties decreased in value with both age and depth of storage. Neither anaerobic nor spore‐forming bacterial numbers were greatly affected by storage.The pH values tended toward neutrality in the deeper parts of the soil stores, and there was less organic matte

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Increasing the ploughing depth and ploughing in grassland has been common in Germany during the past 20 years. Incubation studies were conducted with topsoils from luvisols and gleysols at different times after change of management in order to assess its influence on nitrogen mineralization and its kinetic parameters.The results show that deep ploughing slows the mineralization of nitrogen. The difference between earlier (1967–72) and more recently (1980–82) deepened topsoil has become smaller after a further three years of cultivation, however. The preceding crops (wheat or sugar beet), the amount of N fertilizer as well as clay and nitrogen contents cause a variation in N mineralization. The results indicate a continuing approach of an‘equilibrium’organic matter and nitrogen content. The enrichment capacity of intensively managed soils may be replenished within 10 years.Gleysols formerly under grass mineralize more nitrogen than‘traditionally’ploughed soils, even 27 years after the ploughing‐in. While nitrogen from easily decomposable materials decreases within the first 10 years, the resistant fraction is a long‐lasting determinant for N mineralization. Both processes need to be considered when applying fertilizer to minimize n

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Water samples from ditches draining small upland areas in mid‐Wales were collected before, during and after the improvement of the pasture using two different cultivation techniques. The samples were analysed for nitrogen, phosphorus, potassium and pH. The greatest release was associated with disc harrowing where nitrogen, in its nitrate form, exceeded European Economic Community maximum recommended concentrations for potable water supply for two weeks. Smaller losses of nitrogen, in the ammonium form, and of ortho‐phosphate were observed following a minimum cultivation technique. It is concluded that, on a scale normally associated with upland Britain, pasture improvement is not likely to deteriorate significantly the quality of runoff within water supply catchments. This is confirmed by the results obtained from monitoring streamflow from catchments in which some degree of pasture improvement had been undertaken in the p

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Changes in aggregate stability, density, and porosity as well as the water retention and nutrient contents of different aggregate size fractions due to intensive tillage were investigated. Three soils from Vicarello, Fagna and Gambassi in North Central Italy which had been under permanent vegetation, minimum or conventional tillage for more than seven years were studied. The aggregates on conventionally tilled plots were slightly denser and less porous than those on the untilled or minimum‐tilled plots. The aggregates were less stable under conventional tillage on all soils. Conventional tillage reduced the proportion or macro‐aggregates by 22% at Vicarello and 35% at Gambassi. There were no differences in macro‐aggregate proportions between minimum‐ and conventionally tilled plots at Fagna. The potential of the dry aggregates to distintegrate upon contact with water was greatest in the conventionally tilled and least in the untilled treatments. The proportions of dry macro‐aggregates (>0.25 mm) in the untilled and tilled plots were 90 and 71%, respectively. The soil of the tilled plots contained less carbon and nitrogen than that of the untilled plots in all aggregate size fractions. The silt‐plus‐clay contents of the aggregates accounted for between 65 and 93% of variability in the water they retained at small potentials while organic carbon contents accounted for between 71 and 90% of variability in the stability of the aggregates irrespective of the tilla

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00781.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Direct drilling was compared with mouldboard ploughing on a sandy clay loam using winter wheat as the test crop for a period of four years (1978/79 to 1981/82). The effect of short‐ and long‐term sequences of direct‐drilling on grain yield from 1981/85 was also investigated and in 1983/84 and 1984/85 the effect of soil loosening by a slant‐legged subsoiler, the‘Paraplow'. The range in annual mean yields was 7.19 to 9.32 t ha‐1. There were no significant differences in grain yield between direct‐drilling and ploughing except in 1979 when direct‐drilled wheat yielded 0.60 t ha‐1more than wheat after ploughing. The number of years the land had been direct‐drilled had no effect on grain yield.Using a slant‐legged subsoiler on direct‐drilled land significantly reduced cone resistance and increased root density, but these effects were variable across the working width of the implement. Subsoiling did not increase yield in 1983/84, and in 1984/85 it reduced yield by 0.45 t ha‐1.Long‐term direct drilling of winter wheat on the Tickenham soil series is unlikely to result in a loss of yield provided straw is burnt and

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00782.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Between 1981 and 1987 field experiments were made on loam and sandy loam soils to test the effects of nitrogen, phosphorus and sulphur fertilizers on the yield and quality of linseed, and the uptake of S by the crop. In one experiment, all through the six years, the application of fertilizers up to 60 kg N, 40 kg P2O5and 30 kg S ha‐1increased yields. In the second experiment, the same combination of N, P and S maximized crop yield, uptake of P and S, % oil and oil production. These balanced and optimum rates of fertilizers decreased the percentage of stearic, oleic and linoleic acids but increased that of linolenic acid by accelerating the metabolic pathway of linolenic acid synthesis. Applying P decreased the removal of native S in the soil but when more S was applied, more native S was taken up. Large dressings of P diminished crop yield and quality as well as the availability of native soil

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00783.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0266-0032    

DOI:10.1111/j.1475-2743.1989.tb00784.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY