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Chemistry Quiz




50 g of soil is extracted with NH4Cl (ammonium chloride) and the extract diluted to 0.5 liter. The solution contained the following cations;120 ppm Ca+2 24 ppm Mg+2 1 ppm Na+ 13 ppm K+;a. Estimate the CEC (meq/100g);b. The soil pH is 7.5. Was your estimate of CEC a good estimate? Why or why not?;2. 100 g soil was completely saturated with Al+3 (100% of the CEC is occupied with Al+3). Any excess Al+3 was leached from the soil sample. The exchangeable Al+3 was then exchanged with K+ by adding 1N KCl. The Al+3 in the extract was determined by titration with 150 ml of 0.15 N base. Calculate the CEC.;3. A soil is 75% saturated with Ca+2 + Mg+2 + K+. 50 g of this soil is titrated with 20 ml of 0.1 N NaOH. Calculate the CEC.;4.The following cations were extracted from 100 g soil with at CEC of 20 meq/100g. The soil contained;180 mg Ca+2 36 mg Mg+2 1 mg Na+ 13 mg K+;a. Calculate the % base saturation of the soil.;b. Calculate the lbs/acre foot of each cation.;5.The soil test report show the following data (CEC = 15 meq/100g);Cation lbs/afs;Ca+2 3200;Mg+2 360;Na+ 2;K+ 400;a. Calculate the meq/100 g of each cation and the % base saturation of the soil.;b. Calculate the % acid saturation.;6. A soil is 65% saturated with Ca (CEC = 10 me/100g).;a. Calculate the lb/acre?foot of Ca.;b. Calculate lbs Ca in 1000ft2 (9 inches deep) golf green (1.1 g/cm3 bulk density).;c. Calculate the grams of Ca in a 2 kg container pot.;7. A grower wants to grow clover in two separate fields. Calculate lime requirement (lbs/afs) to increase pH to 6.8 in BOTH fields. Use diagram below.;Field 1 ? loam, pH 5.0, 50% BS, CEC = 10 meq/100g;Field 2 ? clay, pH 5.0, 50% BS, CEC = 20 meq/100g;8. We want to raise the soil pH from 5.5 to 6.5. The CEC is 28 meq/100g. Calculate the lime requirement in lbs/afs, lbs/1000ft2, and lbs/1000 lbs of potting soil mix (ECC = 80%).;9. A fairway soil has pH 4.5 and CEC = 12 meq/100g. A golf course superintendent received a lime recommendation of 100 lbs/1000 ft2. Using the diagram below, estimate the final pH;10. A laboratory analysis showed the following results;CEC = 20 meq/100g soil solution Ca = 6 meq/1;CaCO3 = 0.2% soil solution Mg = 2 meq/1;pH = 8.6 soil solution Na = 36 meq/1;EC = 5.0 mmhos/cm;a.Calculate SAR, ESR, and ESP;b.Calculate the Gypsum (lbs/afs) required to reduce ESP to 5%.;c.Does the soil contain enough lime to reduce ESP to 5% if S were used instead of gypsum? How much S (lbs/afs) is required to reduce ESP?;11. A farmer wants to grow wheat on a sodic soil. The CEC = 30 meq/100g and the ESP = 18%. He needs to reduce the ESP to 6%. Calculate the gypsum required (lbs/A?ft) to amend this soil. What is the minimum quantity of lime the soil must contain to use S as an amendment (express as %CaCO3)? Calculate the quantity of S needed (lbs/a-ft).;12.A laboratory analysis showed that a silt loam soil contained 4 meq Na+/per 100g soil. Soil pH = 8.7 and CEC = 15 meq/100g soil. The exchangeable K+ percent is 4%. What is the ESR of this soil? Determine the amount of CaSO4?2H2O needed to reduce the exchangeable Na+ to 5% in the surface foot of soil.;13.A golf course manager has a golf green that is thinning. A soil test indicates that the following;CEC = 4 meq/100g 800 ppm Ca (soil);pH = 8.4 48 ppm Mg (soil);EC = 8 mmhos/cm 78 ppm K (soil);230 ppm Na (soil);What would you recommend (lbs/1000ft2)? Show all calculations;14. A NC Coastal Plain organic soil has a pH of 4.5 and a CEC = 30 meq/100g. What lime rate would you recommend? A dealer sells 80% CCE lime with the following characteristics: 50% < 60 mesh, 30% 8 mesh. How much lime material would you apply? Use curve below and show all work.;15.Answer the following questions for the soil data listed below.;Exchangeable Cations Cations in Saturated Extract;(ppm Soil) (ppm solution);Ca 1600 180;Mg 600 20;Na 1000 900;K 600 5;CEC (me/100g) = 17 pH (sat'd paste) = 8.6;CaCO3 (%) = 2 ECse (mmho/cm) = 4.5;a. Calculate CEC and compare with measured CEC. Suggest a reason why the two values may be different.;b. Calculate SAR and estimate SAR from the exchangeable cation data.;c. Calculate and estimate ESR and ESP.


Paper#35451 | Written in 18-Jul-2015

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