Hub and Spokes Nutrient Management

January-March 2002

George Cummins , crop specialist

The ISU Northeast Research Farm near Nashua (the Hub) has conducted agronomic research related to soil fertility and nutrient management for the past 25 years; has been considered the premier water quality research site in the Upper Midwest for the past 12 years; and has conducted a well-known Precision Agriculture Demonstration Project for the past 5 growing seasons. Current extension recommendations and public policy related to soil fertility and water quality have been developed from these research findings. Awareness of the research farm and its programs, participation in research farm activities and adoption of many of these practices has lagged in recent years. A way needs to be found to increase interest in the research farm and its activities and to raise the credibility of the recommendations related to the varied farming conditions and farming systems in the 20 county area served by the Northeast Iowa Ag Experimental Association.

Response :
The Hub/Spokes Model of Nutrient Management Demonstration Project proposal was approved in early April, 2001. The strategy of the project was to organize replicated trials with on-farm cooperators (Spokes) as an extension/dissemination strategy. Our initial effort focused on N utilization from manure and commercial fertilizer sources. Manure analysis, the Late Spring Nitrate Test (LSNT) and the Fall Stalk Nitrate Test (FSNT), GPS/GIS technology, and economic response were used to provide cooperators with appropriate information for nutrient- management decision-making.

Twelve separate replicated on-farm demonstrations were completed by 9 cooperators in 6 counties. The demonstrations included 6 Manure X N Rate in a C-Sbn Rotation; 2 Manure X N Rate in a C-C Rotation; 2 Commercial N Rate in a C-Sbn Rotation; a N Rate/Time of Application in a C-Sbn Rotation; and N Rate in Corn following Alfalfa.

Nitrogen management topics and site tours were included in five summer crop tours/field days attended by over 600 people. Agriculture students at Riceville High School , Charles City High School and Hawkeye Community College were cooperators and took an active role in sampling, data collection and data interpretation. Research and cooperator results were included in project newsletters, on extension websites, and in crop clinic/crop conference presentations. Project cooperators will be included in an ISU Documentation of Change study of all IFLM participants.

A follow-up meeting was held at the Northeast Research Farm on December 19th. Cooperators, campus research and extension staff and agency representatives participated.
Project cooperators made the following observations:
a. On-farm results(Spokes) were generally consistent with research farm results (Hub).
b. Actual manure analysis data varied from common book values.
c. Actual nitrogen (N) and phosphrous (P) application rates exceeded planned amounts
d. Optimal corn yields can be achieved with manure or alfalfa credits alone.
e. Reduced commercial N rates (50-60# less than the cooperators normal rate) produced
optimal corn yields.
f. The Late Spring Nitrate Test results require interpretation based on application
methods, materials, timing and weather conditions.
g. Differences in Fall Stalk Nitrate Test results were generally consistent with yield

ISU sociologists are conducting a survey and individual interviews with project cooperators. The original goals of the Hub and Spoke Project were to:
a. Increase awareness of and interest in the research work conducted at the Northeast Research Farm
b. To confirm research findings on-farm using cooperator farming systems
c. To introduce cooperators to the various “tools” used to make nutrient management decisions
d. To demonstrate the economic advantage and environmental impact of various nutrient management practices.
The cooperator survey and individual interviews will help us critically evaluate the impact of our first year's efforts and how successful we were in meeting our original goals. The project budget of $38,150 provided the opportunity for some salary savings and cost recovery for travel and program expenses related to the project.
An expanded Hub and Spokes Manure Tillage Demonstration Project has been funded for the coming year. A project coordinator has been hired and on-farm cooperators are being lined up for the coming growing season. The new project will hopefully build on the success of the initial Hub and Spoke Project Model.


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