| What type of cropping was discovered to caused soil erosion and leaching of nutrients more than others in the Houghton Report 1996 on The Sustainable Use of Soil? | These losses were most common on arable land under continuous winter cereal cropping. |
| What forms the structure of soil? | The way individual particles of sand, silt and clay are arranged. |
| What forms the texture of soil? | The amount of primary particles of sand, silt and clay, in the soil. |
| Coarse-textured sandy soil come from such minerals as? | Sandstone and granite |
| Fine-textured soils come from such base rock as? | Mudstone and slate |
| What are the components of a well managed soil? | 45% Minerals, 5% Organic Matter, 25% Air and 25% Water |
| What mineral plays no part in nutrient retention? | Quartz (silicon dioxide), because it is chemically unreactive. |
| What role does sodium hydroxide play in soil texture testing? | It separates individual particles. |
| What role does hydrogen peroxide play in soil texture testing? | It destroys organic matter. |
| What mineral is very reactive? | Clay minerals are. |
| What affects the reactiveness of minerals? | An increasing surface area with a decreasing particle size. |
| How much water does a clay loam soil generally retain? | 50-60% water |
| How much water does a sandy loam soil generally retain? | 25-30% water |
| What causes the formation and development of soils? | Mineral particles of sand, silt and clay mixed with organic matter by soil organisms. |
| What is the most important aid in soil structure development? | Organic matter |
| What are the soil characteristics that aid in soil structure development? | In order of importance:
Organic Matter, Clay, Calcium Carbonate, and Iron Oxide. |
| What are the characteristics of well structured soil? | High porosity, low density, adequate water storage, free drainage and movement of air within the soil profile. |
| What are the indicators of well structured soil shown by a plants root system? | A fine fibrous root system |
| What is Tilth? | Finely structured surface soils that have been worked through cultivation into ideal conditions for germination and growth. |
| What is Bulk Density in soils? | The mass of oven-dry soil per unit volume, dependant on the densities of the constituent soil particles and how they are packed together. |
| What is the minimum level of volume of macropores in soil, before there is insufficient air for root respiration. | It must not fall below 10% |
| When performing soil structure testing, how long should each side of the soil pit be? | 15 - 20 cm |
| When performing soil structure testing, how deep should the soil pit be? | 25cm deep |
| What are Macrofauna soil organisms? | These are the structural engineers of soils. They incorporate organic matter, create aeration, and provide channels for root growth. Examples are: Ants, beetles, earthworms, moles, millipedes and spiders. |
| What are Mesofauna soil organisms? | These are the organisms that break down organic matter, feed on bacteria or fungi, but may also eat dead organic matter and help nutrient cycling. Examples are: Mites and Springtails (Collembola) |
| What are Microfauna soil organisms? | These organisms are Protists and Nematodes. They release nutrients useful to plants. Nematodes are a diverse group, including plant parasites and predators that feed on bacteria, fungi or other nematodes. Protists, for the most part, feed off soil bacteria. |
| What are Microorganisms in soils? | These are the bacteria, fungi and viruses in the soil. They help in soil stability (aggregate formation), decomposition of organic matter, nutrient cycling, nutrient uptake by plants, disease suppression, induced systemic resistance, plant growth promotion, production of antibiotics and hormones, and the breakdown of toxins (pesticides, pollutants). |
| What are Arbuscular mycorrhizal fungi? | Fungi who form associations with plants, living within the root tissue itself improving nutrient uptake, in particular phosphorus. |
| What are Ectomycorrhizal fungi? | Fungi who form a sheath around the root, increasing the volume of soil that can be accessed for nutrients. |
| What are Nitrogen-fixing rhizobia? | Bacteria who are associated with leguminous plant's roots fixing atmospheric nitrogen into a form that is useable by the plant. |
| What are Plant growth-promoting rhizobacteria (PGPR)? | bacteria that colonise plant roots and benefit plants through mechanisms such as suppression of plant disease, production of antibiotics, improved nutrient acquisition, or phytohormone production. |
| What are Deleterious microorganisms? | Microbial interactions in the rhizosphere that have a detrimental effect on the plant without visible symptoms. |
