Vyhodnocení vhodnosti kalů z těžby štěrku a písku pro využití jako půdní podloží

Bc. Lucie Mašková

Master's thesis

Evaluation of Silt from Sand and Gravel Processing as a Suitable Subsoil Material

Abstract:

Sand and gravel processing generates large amounts of fine particles (< 63 μm) which constitute approximately 20 % of quarry production in the UK. There is, however, no market for this by-product therefore industry treats this material as a waste. Quarries often face shortage of soil to use in restorations and have to look for other options to restore land successfully. This study investigated possible use of silt as a subsoil medium to partially substitute soil-forming materials while facilitating successful crop establishment. In a glasshouse pot experiment, topsoil and subsoil layering has been simulated, generating an artificial subsoil medium by mixing two quarry waste materials: silt and overburden. These were blended in three different ratios (100:0, 70:30, 50:50), aiming for high use of silt. Pots were packed in two bulk densities and sown with three cover crop treatments, being winter rye (Secale cereale), white mustard (Sinapis alba) and a Tarmac grassland seed mixture (Lolium perenne, Phleum pratense, Poa pratensis, Festuca rubra). Three weeks into experiment, mustard displayed first signs of nitrogen deficiency, with phosphorus and potassium deficiencies following later. Rye exhibited minor effects four weeks into growth, grassland mixture showed barely any. Nutrient deficiency visibly inhibited growth of aboveground biomass of Mustard. Root development of mustard with tap roots was the worst in comparison with fine roots of grasses. Both grassland mix and rye performed well. Silt, especially if blended with another growing medium, is suitable as a subsoil medium for successful grass cover crops establishment and initiation of the soil forming process. Mustard cannot be recommended as a suitable cover crop where silt is used as a subsoil medium. Future studies are recommended in order to further investigate long term subsoil and topsoil structural and hydrological connectivity induced by different cover crop mixtures.

Abstract:

Sand and gravel processing generates large amounts of fine particles (< 63 μm) which constitute approximately 20 % of quarry production in the UK. There is, however, no market for this by-product therefore industry treats this material as a waste. Quarries often face shortage of soil to use in restorations and have to look for other options to restore land successfully. This study investigated possible use of silt as a subsoil medium to partially substitute soil-forming materials while facilitating successful crop establishment. In a glasshouse pot experiment, topsoil and subsoil layering has been simulated, generating an artificial subsoil medium by mixing two quarry waste materials: silt and overburden. These were blended in three different ratios (100:0, 70:30, 50:50), aiming for high use of silt. Pots were packed in two bulk densities and sown with three cover crop treatments, being winter rye (Secale cereale), white mustard (Sinapis alba) and a Tarmac grassland seed mixture (Lolium perenne, Phleum pratense, Poa pratensis, Festuca rubra). Three weeks into experiment, mustard displayed first signs of nitrogen deficiency, with phosphorus and potassium deficiencies following later. Rye exhibited minor effects four weeks into growth, grassland mixture showed barely any. Nutrient deficiency visibly inhibited growth of aboveground biomass of Mustard. Root development of mustard with tap roots was the worst in comparison with fine roots of grasses. Both grassland mix and rye performed well. Silt, especially if blended with another growing medium, is suitable as a subsoil medium for successful grass cover crops establishment and initiation of the soil forming process. Mustard cannot be recommended as a suitable cover crop where silt is used as a subsoil medium. Future studies are recommended in order to further investigate long term subsoil and topsoil structural and hydrological connectivity induced by different cover crop mixtures.

Keywords

Secale cereale, Sinapis alba, Restoration, Sand and gravel extraction, Root density, Quarry waste

Keywords

Secale cereale, Sinapis alba, Restoration, Sand and gravel extraction, Root density, Quarry waste

Language used: Czech

Date on which the thesis was submitted / produced: 28. 3. 2018

Thesis defence

• Supervisor: Mgr. Alena Walmsley, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Landscape Engineering / Regional Environmental Administration