Case Study Evidence of New Opportunities for Farm Management Specialists in Spatial Analysis of On- farm Trial Data Terry Griffin 1, Craig Dobbins 2, Jess.

Case Study Evidence of New Opportunities for Farm Management Specialists in Spatial Analysis of On-farm Trial Data

Terry Griffin1, Craig Dobbins2, Jess Lowenberg-DeBoer2

1University of Arkansas – Cooperative Extension Service

2Department of Agricultural Economics, Purdue University

National Farm Management Conference

Motivation

• On-farm trials often violate statistical assumptions

• Farmers continue to conduct on-farm trials– PA and GPS lead to resurgence of on-farm trials– Harvested with yield monitors w/out interference

• Reduced public research funding– More weight on local on-farm experiments

• Farmers’ objective: make best decision

Goal of Case Study Research

• Better understand the motivations of farmers for conducting field-scale experiments and document their perceptions of spatial analysis

• Propose plan to Extension and industry for spatial analysis service

Research Methods

• Case studies evaluated perceptions of conducting on-farm research and spatial analysis

• Qualitative research methods

• Lack of general information to conduct quantitative survey

Multiple Case Study Data• Reference and comparison group farmers

– IL, IN, KY, Ontario

• Direct 3 year observation of reference group – During farm-visits, frequent communication– Farmers conducting field-scale on-farm trials – Spatial analysis reports provided to farmers

• One-on-one interviews of both groups

• Two yield monitor data analysis workshops

Spatial Analysis: A Definition• Spatial statistics assume that data is spatially

correlated and explicitly included in analysis; in contrast to independent observations assumption.

• Yield monitor and site-specific data is spatially correlated. If that correlation is not accounted for in the analysis, results will be biased and misleading.

• Yield monitor data with appropriate spatial analysis can lead to more reliable decision making with limited replications.

Spatial Analysis Reports• Description of on-farm trial

– Design, treatment, data available

• Data handling procedures– Yield data filtering, data assimilation

• Spatial statistical analysis and diagnostics

• Economic analysis

• Production recommendation

Example On-Farm TrialExample On-Farm Trial

• Central Indiana soybean seeding rate trialCentral Indiana soybean seeding rate trial– 80, 100, 120, 140, and 160K seeds per acre80, 100, 120, 140, and 160K seeds per acre– 4 replications in 1700 foot strips4 replications in 1700 foot strips– 30 inch rows30 inch rows

• End result is more reliable informationEnd result is more reliable information– A production recommendationA production recommendation– Not a mapNot a map

Photo: Griffin – Twilight Farms

Raw yield monitor data • As-is from the combine• No cleaning or filtering

Yield data in GIS after removing erroneous observations

Study area

Yield data in GIS after removing erroneous observations

Yield monitor data used in analysis

Rate trial: 80K to 160K seeds per acreFour replications of five population rates

{{{{1

2

3

4

Major soilSecondary soil

All five rates oneach soil “zone”{

Minor eroded soil

Spatial Error Estimation

Variable

Spatial error

Coefficient t-Statistic

CONSTANT 64.141*** 17.38

POP 0.176*** 3.50

POP_SQ -0.001*** -2.81

Soil3 -246.321 -1.01

Soil2 -356.830*** -3.92

POP*Soil3 0.117*** 5.44

POP_Soil2 0.023*** 2.59

ELV*Soil3 0.271 0.94

ELV*Soil2 0.417*** 3.86

POP*ELV -0.002 -1.49

ELV -0.500*** -3.21

LAMBDA 0.781 63.11

2004 Soybean Seeding Rate Study

50

55

60

65

70

60 80 100 120 140 160 180

Seeding rate (000 seed ac-1)

Yie

ld (b

u ac

-1)

Major soil Secondary soil Minor soil

Major soil: 130K yield maxMajor soil :

100K profit max

Secondary soil: 150K yield maxSecondary soil:

120K profit max

Can reduce input costs by lowering seeding population from 130K to about 100K on most of the field, increasing planting timeliness

Yield Data Analysis Workshops• November 2005 and March 2007

• Farmers, consultants, university personnel

Who should conduct spatial analysis?

• Farmers– some farmers perform own spatial analysis

• University Extension– Technical skill, but can only work directly with a

few farmers

• Private industry– farmers, co-op, dedicated analysts, consultants

Role of Extension• Assist with designing experiments

• Network of research collaborators– Regional research projects

• Continued education/training for analysts

• Troubleshooting and problem solving

• Teaching interpretation of analysis

• Assist with decision making

Comparative Advantage for Farm Management Analysts

• Already dealing with vast amounts of data

• Familiar with assisting interpretation of results

• Assist with whole-farm decision making

Farmers’ Willingness to Pay

• Will farmers be willing to pay a fee that entices qualified analysts to offer service?

Farmer D F W P T

What would you expect to pay for full-service spatial analysis?

$3 per acre

$5 per acre or $500 per trial.

Percent of predicted value. Up to several hundred dollars.

$2 per acre. Up to $500 per trial.

$5 to $10 per acre or 40 to 50% of payback.

Third-party Spatial Analysts Questions

• What software to assemble the data?• What software to statistically analyze the data?

– R, GeoDa, Stata, SpaceStat, MATLAB, SAS

• What type of spatial analysis conducted?– How characteristics of neighboring data used?

• Where received spatial analysis training?• How confident are you in the results?• Does client receive copy of original or raw data?• Is focus on providing maps or recommendations?

Conclusions• More confidence in data and decisions when using

spatial analysis– Farmers made more decisions more quickly

• Unclear who will be primary analysis provider• Role for Extension and private sector industry

– Depends upon farmers’ willingness to pay

– Will any tax money be put into this?

– Are any public goods generated?

• Farm management specialists may be among the first to demonstrate benefits of the yield monitor

Wish to thank USDA-SARE for providing funding to evaluate alternative on-farm designs and develop spatial analysis methods

Terry Griffin

tgriffin@uaex.edu

501.249.6360(O)

Craig Dobbins

cdobbins@purdue.edu

Jess Lowenberg-DeBoer

lowenbej@purdue.edu