SCSC 301 Final Exam Questions With Complete Solutions

A soil has a bulk density of 1.3 g/cm^3, a particle density of 2.6g/cm^3, a total porosity of .5 and a gravimetric water content of 0.2. Calculate the water-filled porosity. correct answer: .26 After a growing season of heavy tillage traffic across a soil, a soil property that is affected is: correct answer: bulk density From a biological point of view, the most important role of structural development in clayey textured soils is to provide an increase in: correct answer: macro porosity The quantity of light reflected by a soil is called: correct answer: value A word used to describe the consistence of a soil is: correct answer: friable Calculate the mass of one hectare of soil in kg to 15 cm depth. correct answer: 2,250,038 In a soil having a color of 10YR 4/1, the chroma is: correct answer: 1 At a given partial pressure gradient, diffusion is a function of: correct answer: air-filled porosity A principal role of oxygen in soils is: correct answer: oxidation of organic matter Considering a soil as a medium for plant growth in terms of aeration, water supply, and temp, the most desirable structural type is: correct answer: granular Under normal aerated conditions, soil air compared to the atmospheric air is almost always contains the same percentage of: correct answer: N2 The soil components--air, solution, solids--arranged in order of increasing heat capacity (lowest heat capacity first) are: correct answer: air, solids, solution In a clay loam soil horizon having a fine, platy structure, the soil aeration is likely to be: correct answer: poor Daily fluctuations in temp at 15 cm below the soil surface, when compared to daily fluctuations at the soil surface: correct answer: occur later in the day The subsoil in College Station is cooler than either the surface soil or the parent material: correct answer: in early spring Water in soil is: correct answer: a transporting medium The amount of heat stored in the soil in the spring at a given location is primarily a function of soil: correct answer: moisture Water which moves in all directions in a soil consists of water which moves in response to difference in: correct answer: matric potential only Available water in soils is water held between field capacity and: correct answer: wilting coefficient In a soil layer containing large holes or channels closed at the surface, water enters the large holes: correct answer: only after the surrounding soil is saturated Water enters a very sandy subsoil from a clayey surface soil: correct answer: only after the clayey soil is saturated A common primary silicate mineral which weathers to form secondary silicate minerals in soils is: correct answer: feldspars A typical moist surface soil contains approximately 25% by volume ___________. correct answer: water One of the most soluble and therefore, easily weather minerals is: correct answer: sylvite A primary silicate mineral that does not weather to other silicate minerals is: correct answer: quartz The properties of soil are mainly due to the combine effects of __________ acting on parent material over time/ correct answer: climate and biota A property used in distinguishing among minerals in hand-held specimens is: correct answer: luster The soil horizons that the soil solum consist of are: correct answer: O, A, E, B Soils which support aerobic plant growth must contain: correct answer: gaseous oxygen