1 given the information below calculate the

Question

1. Given the information below, calculate the following.

profile NO₃-N = 10 lbs/A Previous crop = wheat

Soil OM content = 2.0% 60 bu/a

Soil OM degradation rate = 1%/year 100 lb residue/bu

40% residue C

C:N = 100

a. Additional N needed to degrade all the residue. (lb N/A)

b.The farmer wants to plant sorghum next season. How much total fertilizer N will he need to apply if he raises 100 bu/A (test weight = 56 lb/bu; grain N = 1.5%; residue = 50 lb/bu; residue N = 0.6%).

2. Lawn fescue contains a C:N ratio of 30:1 and we return 3000 lb/ac per year to the soil. Assume 40% C content.

a. Will available soil N be depleted if the soil contains 4% soil OM and decomposes at a rate of 1% per year?

3. 6.8g of ammonium nitrate containing 34% N is added to 3,000g of soil for a greenhouse experiment. Calculate the following based on the soil weight:

a. ppm NO₃^- added

b. ppm NH₄⁺ added

c. % fertilizer N in soil after addition

d. lbs of actual N/ acre-foot of soil

 

4. A farmer wants to apply 150 lbs N/a.

 

a. How many kg/ha anhydrous ammonia does he need?

b. How many lbs/a urea does he need?

c. How many lbs/a urea ammonium nitrate does he need?

 

7. Given the following information, estimate the N rate needed for 150 lb/1000 ft²Bermudagrass?

Previous year's Bermuda crop: 150 lb/1000 ft²  40% residue C; Residue C:N = 50

next year's bermuda crop: 150 lb/1000 ft² 2% N in clippings

Soil Data:  2% OM             1% OM loss/yr

What would the N rate be if 100 lbs /1000 ft² of the grass clippings were removed?

8. A grower applies 100 lb/a of 10-34-0.

a. Calculate the lb P₂O₅/a applied.

b. Calculate the lbs P/a applied

c. Calculate application rate in lb P₂O₅/1000 ft²

d. Calculate the g P₂O₅/kg potting soil.