Class Number_______
Agronomy 354 Problem Set 5
Spring 2016
Problem sets are due ca. one week after they are handed out in lecture. To receive full
credit (4 points each), work must be shown as to how the answer was obtained, the
correct answer must be written on the indicated line, the units of the answer must be
indicated and correct, and the assignment must be handed-in by the due date. Check
the course homepage for sample problems and solutions.
1. Calculate the P analysis of CaMg(HPO4)2 on an elemental and oxide basis.
_________ (elemental)
_________ (oxide)
2. The soil test report calls for 98 lb/acre of P2O5 but you only have an area 188 ft X 220
ft to fertilize. How many pounds of 0-46-0 (oxide) are needed? (Remember, an acre
is 43,560 sq ft.)
_________
3. The soil test calls for 120 lb per acre of N. Forty lb/ac of urea (46-0-0) is applied
preplant. How many lb per acre of anhydrous ammonia (82-0-0) must be sidedressed to meet the remaining N needs?
_________
4. If N is worth 96¢ per lb and a ton of pure KNO3 sells for $492, how much are you
paying per lb of K2O? Hint: must determine the pounds of N and K2O (convert the K
to oxide basis) per 2000 pounds of KNO3.
_________
5. Assume that you wish to make a bulk blend. Per ton, you add 400 lb of 46-0-0, 800
lb of 11-52-0, and 800 lb of 0-0-62. What is the analysis of this blend (all are on the
oxide basis)?
_________