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).