Simultaneous Diffusion of Herbicide Tolerant Cotton and Conservation Tillage

1
Simultaneous Diffusion of Herbicide Tolerant
Cotton and Conservation Tillage

• George B. Frisvold, University of Arizona
• Abigail Boor, American Express
• Jeanne M. Reeves, Cotton Incorporated
• Cotton Economics and Marketing Conference
• Beltwide Cotton Conferences
• New Orleans, LA January 9 12

2
Research Questions

• Does diffusion of herbicide-tolerant (HT) cotton
  encourage diffusion of conservation tillage?
• Does diffusion of conservation tillage practices
  encourage diffusion of HT cotton?
• What other economic or agronomic factors explain
  technology diffusion?

3
Methods

• Simultaneous equation estimation of two dynamic
  diffusion curves
• 3SLS estimation to account for simultaneity of
  diffusion

4
Data

• State-level time series cross section data from
  1997 2002
• HT cotton adoption data from USDA AMS
• Conservation tillage data from CTIC

5
Logistic Diffusion Curve
Adopting
K Adoption Ceiling
b characterizes speed of movement from a to K
Time
a characterizes initial adoption
6
Effect of b on Diffusion Rate
Adopting
Fast Adoption Large b
Slow Adoption Small b
Time
7
Diffusion Curves for HT Cotton and Conservation
Tillage
HTit Ki / 1 exp ( ai bit t uit )
CTit Zi / 1 exp ( ci dit t vit )
HTit of States cotton acres planted to HT
cotton

CTit of States cotton acres adopting
conservation tillage
Ki , Zi adoption ceiling parameters
8
Technology Availability Parameters
ai , ci origin or technology supply parameters
ai a0 a1 PARENT a2 CALAW

ci c0
9
Technology Acceptance Variables
bi , di acceptance or diffusion rate parameters
bi b0 b1 ln(CTit) b2 COTPRICE b3
GLYPHPRICE b4 PCHARVEST

di d0 d1 ln(HTit) d2 COTPRICE d3
PRECIP d4 LANDVALUE d5 PCHEL
10
HT Cotton Diffusion Curve Regression
Coefficient Variable Description Parameter Estimate t-value
Availability variables
a0 Intercept -6.43 -10.55
a1 PARENT 2.12 3.35
a2 CALAW -9.92 -11.75
Acceptance variables
b0 YEAR -7.47 -1.71
b1 ln(CT) 0.11 3.84
b2 COTPRICE 0.47 2.13
b3 GLYPHPRICE 1.86 1.60
b4 PCHARVEST 2.79 2.88
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Conservation Tillage Diffusion Curve Regression
Variable Description Parameter Estimate t-value
Availability variable
c0 Intercept -1.55 -4.06
Acceptance variables
d0 YEAR -0.86 -3.14
d1 ln(HT) 0.19 4.99
d2 COTPRICE 0.07 0.48
d3 PRECIP 0.25 7.13
d4 LANDVALUE -0.0001 -3.00
d5 PCHEL 0.94 6.53
12
Cross Elasticities ofTechnology Adoption
 Elasticity of Mean Minimum Maximum
CT adoption w.r.t HT cotton adoption 0.48 0.13 1.14
HT cotton adoption w.r.t CT adoption 0.16 0.01 0.46
13
Conclusions

• Diffusion of conservation tillage and
• herbicide resistant cotton are mutually
  reinforcing
• At sample means
• A 1 increase in a states adoption rate for HT
  cotton increases the states adoption rate for
  conservation tillage by 0.48
• A 1 increase in the adoption rate of
  conservation tillage increases the adoption rate
  of HT cotton by 0.16

14
Conclusions

• Other factors affecting HT cotton adoption
• Availability of seed varieties adapted to local
  conditions
• Cotton price
• Harvested / planted acres
• Other factors affecting conservation tillage
  adoption
• Extent of HEL land
• Precipitation
• Land values (a proxy for urbanization)