Agron 182 S19 Exam 1

Agronomy 182 Exam 1 Name: 1) Horizons matching (6) A Horizon ____ Organic horizon B Horizon ____ Zone of accumulation C Horizon ____ Undeveloped, unconsolidated horizon E Horizon ____ Mineral horizon with organic enrichment O Horizon ____ Consolidated bedrock R Horizon ____ Horizon with eluviation and without organic matter 2) Match the following soils to their respective textural classes. (4) a) 33% Sand; 33% Silt; 34% Clay ____ Silt Loam b) 45% Sand; 35% Silt; 20% Clay ____ Clay Loam c) 65% Sand; 10% Silt; 25% Clay ____ Loam d) 20% Sand; 60% Silt; 20% Clay ____ Sandy Clay Loam 3) Which of the following is expected to have the least amount of available water: (2) a) Loamy sand b) Sandy loam c) Sandy clay loam 4) T/F Clay textured soils will be poorly drained (2) 5) T/F I expect residuum soils to weather more quickly than glacial till (2) 6) T/F I expect the upper slope (shoulder and upper backslope) to be more developed than the summit (2) 7) T/F I can determine soil texture from observing soil color (2) 8) As organic matter increases, I expect the soil color to __________________. Whereas, if the soil is more weathered, I expect more ________________ colors. (4) 9) Circle all of the following true statements about the color 10YR 5/2? (3) a) This is a more weathered soil, based upon the 10YR page b) This soil has a high value and low chroma, indicating potential wetness c) This soil has low value and chroma, indicating high organic matter 10) Match each structure to where you might find it in the soil profile: (6) a) Single grained ____ Loamy C horizon b) Blocky ____ High organic matter containing A horizon c) Massive ____ B horizon with sodium accumulation d) Columnar ____ Compacted, tilled, or lower OM A horizon e) Granular ____ E horizon f) Platy ____ Extremely sandy C horizon

11) Find the best match for the following parent materials and management concerns: (5) a) Alluvium ___ Fine textures may make tillage difficult, may pond b) Residuum ___ Low water holding capacity due to sandy conditions c) Glacial outwash ___ This may become unfarmable with excessive erosion d) Loess ___ Area likely more susceptible to erosion due to texture e) Lacustrine ___ Area may flood or texture may change quickly 12) In an idealized soil, roughly half of the soil would be expected to be solid material and roughly half would be pore space. What is contained in the pore space? (3) 13) Match each subgroup to its soil order:(5) Circle the most poorly drained soil on the list(2) a) Udic Haplustepts ____ Vertisol b) Typic Hapludoll ____ Alfisol c) Mollic Hapludalf ____ Andisol d) Aquic Haploxerand ____ Mollisol e) Aeric Haplaquerts ____ Inceptisol 14) Which of the following soils is classified to the great group level? (2) a) Mollisol b) Endoaquoll c) Typic Hapludoll d) Aquoll 15) Select all true statements about the World Reference Base soil classification: (4) a) It is relatively young, developed in the last 25 years b) It combines aspects of other major systems c) It is associated with the Food and Agriculture Organization of the United Nations d) Instead of soil orders, there are reference soil groups 16) A soil series is ____________________________________________________(2) 17) A horizon is designated a Btssg. Discuss what is happening in this horizon: (4) 18) Many antibiotics are derived from ___________________________ (2)

23) Discuss three different soil orders-where in the world might you find them and what might that mean for management? (6) 24) Draw a general landscape. Where might you find the youngest and oldest/most developed soils on the landscape? Why? (5) 25) How might you go about determining the texture of the soil in the field? (5) 26) Write one additional short answer question that I should have put on this exam AND your answer to the question (4)