Question

Soil testing laboratories usually estimate cation-exchange capacity (CEC) as the sum of Ca2", Mg, and K displaced during extractions with neutral, 1 N ammonium acetate (NH 0Ac), which are performed primarily to test for available K. The following data were thereby obtained for three contrasting soils, but have been reported as pounds per acre for each of the three elements, assuming the conventional weight of 2 million pounds for an acre of soil 6 inches deep. Soil A 4004 381 1108 Soil B 1043 108 202 Soil C Ca2 Mg K* 11210 1734 2013 1. Convert each of the values reported to milliequivalents per 100 grams 2. Calculate the CEC of each soil, assuming the complete absence of other 3. If the three soils are a sand, a sandy 1oam, and a clay loam, identify (meq/100 g). cations. Express your answers in meq/100 g. how these textures correspond to soils A, B, and C in the above table.

Answer 1

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, ว million Pourdo el foil --> 1108 hurdo lacre oan 0,000,000 founclev - 0.055니7maloomo tMle → 0.055"Yms lin the ame hrocedtvu the valus thu Cotions in iven a亼 Soil ASoil Soil 2 -f ca +505 Meg I 303 Meq,4012 Mee 4/205 M 0.25 M 0-5 802 Micg 258 M .5 801 Me 9) cation exchange catacity i8 the gun 염 mlieorcu vale cations n Meal looams tence, +2. 580 14、012-t 3.612 5 'The CEC ซู Soil-C

3. Sandy loam clay loa M-> Soil-A => 59- CEC