Agron392 Spring2012
Site-specific management for fertilizer/limestone recommendations
Learning outcomes:
 further developed skills in critical thinking and problem-solving in agronomic situations in order to
develop recommendations for nutrient applications with justification
 further developed written and oral communications skills in order to persuade and inform an audience,
using technical appropriate terminology
 further developed computer skills using spreadsheets, databases, geographical information systems,
word processing and presentation software, in order to organize, manage, interpret, and communicate
information
Assignment:
Mr. Schrum has hired you, as an independent crop consultant, to determine the nutrient and limestone
needs of a 150-acre field, called Barn Place. The field is located in Boone Co, Amaqua Township
Section 7, SE corner, T-84N, R-28W. In the fall before planting corn, he hires the local coop to spread
P2O5 and/or K2O fertilizer. In the spring, he typically applies N as anhydrous ammonia. Mr. Schrum
usually applies limestone every four years. He has no livestock, thus uses only commercial fertilizer. He
will be planting corn (97 A) and soybeans (53 A) during the 2013-growing season. Additionally, Mr.
Schrum is wondering if he should apply sulfur on his fields.
Assume that it is 1 Oct. 2012. You will make fertilizer and limestone recommendations using the results
from three different methods for soil sampling:
1. few samples taken for uniform rate application
2. grid sampling (2.5 A cells) with variable rate technology (VRT)
3. management zones with VRT or uniform rate
Part I: Calculate fertilizer/lime requirements, due 20 Feb.
Using your excel spreadsheet, determine the total amount of product and costs for applying the
recommended P2O5 or K2O product for 150 A for 1) uniform rate, 2) grid sampling/variable rate, and
3) management zone sampling.
Using your excel spreadsheet, determine the total amount of limestone product and costs for applying
your recommendation for 150 A for 1) uniform rate, 2) grid sampling/variable rate, and 3)
management zone sampling.
Part II: Create a partial budget for the addition of sulfur, due 27 Feb.
Create a partial budget to determine if the addition of sulfur is profitable. What is your
recommendation? How do you define profitability? What assumptions have you made?
Part III: Draft of narrative explaining recommendations, due 1 March
Prepare a narrative (third person): explaining your recommendation for fertilizer and limestone
applications for the 2013-growing season. Think about this: What are the consequences of each of
the three methods of determining fertility recommendations? For each method, give one positive
and one negative consequence. Consider the economic, environmental, and social aspects.
Part IV: Narrative explaining recommendations, due 5 March
Final draft of narrative explaining recommendations for nutrients and limestone. Include supporting
materials.
Part V: Client presentation, written letter or oral, due 19 March
Prepare a client presentation describing the recommendations that you have developed; provide
supporting materials. You will either participate in an oral, 20-minute presentation to Mr. Schrum,
describing the recommendations that you have developed or you will be asked to write a memo (first
person) to Mr. Schrum, describing the recommendations that you have developed.
Name
Ryan
Colin
Rachel
Zak
Andy
Michael
Ellen
Michelle
Tom
Horace
Barry
Phil
Chris
Joe
David
Casey
Jordan
Matt
Tyler
Kurt
Guan
Cody
Chelsy
Liam
Gardner
Mansager
Owen
Swanson
White
Antenucci
Hopkins
McEnany
Pepper
Tantang
Buehler
Johnson
Meyer
Randolph
Van Oort
Crozier
Krueger
Moorberg
Reimers
Eischeid
Lai
Neill
Sonnichsen
Vincent
Nutrient
P
K
P
K
K
K
P
K
P
K
P
P
P
P
P
K
P
K
K
K
P
K
P
K
Presentation with Mr Schrum
Written
Oral
Written
Oral
Written
Oral
Written
Written
Oral
Oral
Written
Written
Oral
Oral
Written
Written
Oral
Written
Written
Oral
Written
Oral
Written
Oral
Class activities:
(a complete schedule can be found at http://www.agron.iastate.edu/courses/agron392/calendar.htm)
Mon. 13 Feb.
Farm visit
Wed. 15 Feb.
Mon. 20 Feb.
Wed. 22 Feb.
Mon. 27 Feb.
Wed. 29 Feb.
Mon. 5 Mar.
Wed. 7 Mar.
Mon. 19 Mar.
Partial budgeting
Using GIS/SMS to create maps
Nitrogen recommendations
Using GIS/SMS to create maps
Precision agriculture discussion, economics and efficacy
Preparations for client presentations
Client presentations