Flashcards
Soils
Flashcards do conjunto (26)
- 1Hue-The quality of a colour used to distinguish red from green, blue and yellow
Natural orders of hues: Red- yellow - green - blue - purple - 2What's hues defining number? and how are they namedHues have a number from 0 - 100
R, YR, Y, GY, G, BG, B, PB, P, PB - 3Value-Lightness of a colour. Scale ranges from 0-10
0=pure black 10=pure white - 4Chroma =Degree colour is from the neutral colour of same value
- 5Munsell NotationThree colour attributes are assigned the symbols, H, V and C and are written in the form H v/c which is called the munsell notation.
e.g. a vivid red having H, V and c would be 5R 6/14 - 6Soil textureTexture describes the size of particles in a soil.
- 7There is no natural basis for classifying particle- size distribution in soils. Textural triangles are used to assign textual class names to soil.
- 8Bulk density. Particle density.Bulk density is the weight of soil in a given volume. Particle density is defined as the mass per unit volume of soil solids.
- 9Both soil bulk density and particle density are concerned only with the mass of solids in a soil and do not include water.Bulk density is calculated by dividing the mass of a dried sample by the sample volume to give a value in g/cm3
- 10Bulk density plays an important role in determining whether a soil has thephysical characteristics necessary for plant growth, building foundations or other use.
- 11Plant growth can be affected by bulk densitybecause root penetration is inhibited in highly compacted soils with soils that have a naturally high bulk density. Pore size and connectivity play an important role in the movement and availability
- 12A mixture of different sized sand particles (i.e. well graded or poorly sorted sand) are more likelyto have a higher bulk density because the smaller particles tend to fill spaces between the larger grains.
- 13Highly organic matter content usually willlower the bulk density of a soil because of the low particle density of organic matter
- 14bulk density = mass oven dry soil/ total volumee.g.
- 15Redox potential of soil-Redox potential can be thought as a measure of electron 'pressure' and thus the potential severity of reducing conditions.
- 16Soil pHThe degree of soil acidity or alkalinity affects many soil properties. This variable, expressed as the soil pH, largely controls plant nutrient availability and microbial reactions in soils.
- 17Soil ph affectswhich trees, shrubs or grasses will dominate a landscape under natural conditions and determines which cultivated crops will grow or even grow in a soil.
- 18Pure in equilibrium with co2 at atmospheric concentration has a PH of 5.6A soil solution will have either a lower or higher than 5.6 depending upon weather the soil acts as an acid or a base.
- 19When distilled water (ph- 5.6) is added to a soil having a different pH, the pH of the waterchanges to close to PH of the soil. This change occurs in acid soils mainly because Ca2+ and Al3+ in soil solution displace H+ ions from exchange sites on minerals and organic matter.
- 20In calcareous soil Ph is controlled primarily bythe dissolution of CaCO3 which buffers the solution by providing CO32- ions which react with H+ to from HC03- which reduces acidity
- 21ConductivitySoil conductivity can be used as a measure of the total soluble ions in place of the more annoying determination of individual ions.
- 22In situ field determination of conductivity using portable probes is easy and quick.The parameter is useful in monitoring surveys and in assessing the need for irrigation or drainage, and the impacts of fertilization. Plant growth has been linked to the conductivity of soils. Plant growth has been linked to the conductivity of the soil solution.
- 23Soil Alkalinity -Alkalinity in natural waters results primarily from bicarbonates, carbonates, and hydroxides. Alkalinity in soil arises mainly due to the dissolution of calcite ( CaCO3) which causes an increase in Ph. Calcareous, dolomitic and sodic soils.
- 24Soils from arid and semi arid regions may have ph values as high as9.9 Sodic soils may have a ph values of up to 10.5. Soils having a Ph between 7.0 to 8.5 contain free carbonates, while soils with Ph vaues > 8.5 contain varying quantities of carbonates and bicarbonates
- 25ChlorosisHigh concentrations of bicarbonate inhibit Fe and Mn uptake and utilization by plants, which in turn can interfere with the production of chlorophyll.
- 26Reduced yields of tree and bush fruit crops: the low solubility of Fe and Mn in alkaline soils and strong binding of thes metals on himusat high ph intereferes with fe
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- university The Earth FlashCards sobre Soils, criado por frodoisback em 23-04-2015.
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- frodoisback
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