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Abstract
In order to reveal the effects of using mushroom material on the physical properties of reclamation land of coal mining area, took the undamaged land as a contrast, arranged nine sample points, and analyzed the effects of using mushroom material on the physical properties of the reclamation land, such as soil compaction, bulk density, soil moisture, and types of soil particles (clay, silt, sand) etc. The results show that with the time increases, the soil compaction, bulk density of land are also increasd by using mushroom material. Compared with block 3 which doesn't use mushroom material, the surface soil compaction of expected four years application of mushroom material land 4 increases 71%;and the bulk density increases 0.27 g/cm3. Soil compaction increase is due to irrigation and rain, while bulk density increase is due to the misture of decomposed mushroom and soil. Compared with block 3 which doesn't use mushroom material, the surface soil clay of expected four years application of mushroom material land 4 increases 0.6%, and the silt increases 14.27%. Using mushroom material can improve the soil particles distributions and structures and increase the soil content of layers 1~3, which also led to the soil surface compaction and bulk density increase. The mixture of mushroom material and soil increases the resistance of water infiltration and soil moisture. The soil moisture of the land which used mushroom material increases 3%~4%.
In order to study the effects of using mushroom material on the particle composition of reclamation land of coal mining areaauthors chose eight representative experimental plots in state investment reclamation project 2001 of Pingyangsi town Zoucheng city.Took the undamaged land as a contrast and each block is divided into six levels to collect soil sample for analysisand used British Malvern laser particle size analyzer to measure soil particle compositionaccording to SPSS to analyze the soil particles correlation around every block and the undamaged plots.The results show that the essence effect of using mushroom material on soil particle composition is to make use of the decomposition of humus they containedas a binder to increase the proportion of soil microaggregates and to improve soil physical structure.The specific conclusion is that the principal effect of using mushroom material on the particle composition is in the level of 0 to 15.24 cmthe soil particles correlation around the block which have used the mushroom material and the undamaged plots is higher than the block which didn’t use the mushroom materialthe maximum difference is from 0.17 to 0.18 which is measured between plot four which have used mushroom material for four years and plot three which didn’t use itthe soil particles correlation around plot four and the undamaged plots one is 0.940.Thereforethe application of mushroom waste for reclamation soil can be able to improve the physical properties and ameliorate the soil retention of fat and water.
Restoring soil quality is the main evaluation norm of the reclamation. In order to reveal the effects of mushroom waste on the quality improvement of reclaimed soil in coal mining areas, the physical, chemical and microbial characteristics of soil are studied. The results show clear improvement in the soil after using mushroom waste. Because of human cultivation and fertilization, cultivated soil after reclamation exhibits high comprehensive quality and the index of quality of surface soil reaches 0.64 and 0.73. The average index of surface soil quality is as high as 0.52 and 0.54. In comparison, the quality of reclaimed soil of forest land is low, with average index of 0.40. The effects of mushroom waste are mainly on the surface soil in the first 2 years after the application. After that period, with the decomposition of mushroom waste, soil quality index tends to be the same as the original soil. The quality of surface soil is higher than that of subsoil, especially after the application of mushroom waste, at which point the soil quality reaches a peak at about 15 cm. Cultivated soil after reclamation has great variance in quality, after the coefficient of 24.74%. Mushroom waste can reduce such variation, particularly with long-term use. The variance efficient falls to 3.59% after 3-year application.
In order to reveal the spatial-temporal variation law of reclaimed soil compaction in coal mine area, the reclaimed soil compaction variability from vertical and horizontal aspects of five years was analyzed by the testing on the spot and comparing with normal land. The results showed as follows: the reclamation soil surface compaction was the highest with reaching 2050 kPa in first year, and gradually reduced year by year, was the lowest (50 kPa) in the fifth year, and was almost reached the compaction level of unsubsided land. The order spatial variation of soil surface compaction was in the land reclaimed five years(68.40%), next was unsubsided land(52.58%) and the lowest was the land being reclaimed(22.01%); in terms of the variation, the soil compaction is higher and the variation is lower to each soil layer of being reclaimed land, and the compaction of the first three layer is lower but the variation is higher to other redamed land, to the fourth layer(22.86~30.48 cm) is higher and variation is lower, and the compaction under the forth layer is nearly stable.
Heavy agricultural machinery can cause structural degradation in subsoils. Severe structural degradation restricts or even impedes plant growth. Therefore, compaction can only be tolerated in soil horizons that can be structurally reclaimed with reasonable effort, i.e. the upper 0.2 to 0.3 m (plow layer). The pressure exerted by tires of agricultural vehicles is one of the main factors influencing soil compaction. In this study, we present data showing the spatial pressure distribution underneath tires of agricultural vehicles in motion. The pressure was measured directly underneath the tire on a rigid surface as well as underneath a sand layer of 0.3 m. Pressures are strongly reduced by the sand layer. The data measured underneath the sand layer are compared to model data calculated by means of a finite element model. Model and measured data agree well. On the basis of our results, in finite element modeling, we suggest that it is better to use a non-homogeneous load distribution for predicting soil compaction under tires of agricultural machinery.
The major soil horizons of prime farmlands disturbed by surface mining in the USA must be reconstructed during reclamation in accordance with current federal legislation. Consequently, the topsoil (Ap horizon) and subsoil (B and C horizons) are removed and stockpiled separately during overburden removal activities and are replaced over spoil during reclamation in an attempt to reconstruct the original soil profile and to help maintain soil productivity. This study was conducted to investigate the morphological, physical, and chemical properties of reconstructed mine soils and to identify characteristics of these soils that could limit crop growth. We described and sampled a total of 72, 1- to 2-year-old, reconstructed soil profiles at eight reclaimed surface mines throughout western Pennsylvania. Soil depth over spoil was generally >75 cm with an observed range of 5 cm to >2 m. Well-expressed Ap horizons were observed in nearly all profiles. The structure of the reconstructed subsoils was drastically altered by mining to a structureless and massive condition. Excessively compacted shallow soil layers restricted downward penetration of plant roots within 47% of the soil profiles described. Reconstructed soil horizons that are likely to restrict plant growth included horizons composed of spoil, horizons with >50% rock fragments and excessively compacted soil layers. These restrictive soil horizons were found within 1 m of the surface for 57 of the 72 soil profiles described and within 50 cm for 51% of the soil profiles. Morphological investigations of reconstructed soils could be useful for evaluating reclamation success and soil productivity potential.
Contribution from the Dep. of Agronomy, The Pennsylvania State Univ.
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Many of Britain's reclaimed coal-lands are damaged by erosion. Much accelerated runoff and erosion is caused by soil compaction that reduces the land's capacity to absorb rainwater. This study compares conditions in two types of coal-spoil, deep-mine colliery discard and surface-coal-mine overburden, and in four contexts: freshly laid spoil, old unvegetated minespoil, minespoil partly veneered by grass tufts, and ‘reclaimed’ spoils, which are defended by a dense grass turf and (ca. 100 mm) deep artificial topsoil. Bulk density testing reveals a characteristic pattern. The soil is of moderate density (< 1.3 g/cm) in the grass root zone. However, soil densities rise to 1.8 g/cm and more between 30 and 50-cm depth. Particle size and stability tests confirm that minespoils contain a large proportion of water unstable primary particles, mainly mudstones and shales. These break down on wetting, flood the soil with fine particles, and help raise the soil density to levels where water infiltration and root penetration is impeded. Rainfall simulation tests on surface coalmine spoils near Blaenavon, Wales, find that poorly vegetated plots (50-90% cover) convert less rainfall to runoff, and yield a fourth as much sediment as unvegetated plots. Tests of deep coalmine spoils at the Earth Centre Reclamation Project, Doncaster, England, found that newly laid, unvegetated, recently washed and hence stabilised, coal spoils converted only 20% of rainfall to runoff. Older comparted, spoils converted 25-35% of the rainfall to runoff when unvegetated but less than 10% when mantled by thin grass turf. Soil losses for the same rain event were more than four times greater on the unvegetated sites. Finally, on both sites, plots mantled with a deep well-managed layer of applied topsoil sites absorbed most of the rainwater applied in tests. This was subsequently detected running in macropores and fissures below the applied topsoil and in the upper layers of the relatively impermeable mine-spoil subsoil.
The author, who participated with an interdepartmental team in advising the US Congress in writing the Surface Mining Control and Reclamation Act, outlines the often conflicting requirements which determined the genesis of the Act. The paper also discusses the criteria for judging the effectiveness of restoring soil productivity and the emphasis on the restoration of prime farmland. It also notes that the nature of the balance between environmental protection, farmland productivity and the needs of coal are still uncertain and that there is a contradiction in US attempts to alleviate hunger while national soil resources are being destroyed.