COMPARISON OF CARBON EMISSION ASSESMENT USING
EXTENSION BUDGETS AND REAL FARM DATA:
COTTON IN THE TEXAS PLAINS
Sanja Zivkovic
Darren Hudson
INTRODUCTION
 Increasing interest in global warming
 Greenhouse gas (GHG) emissions – potential negative
consequences on the environment
 Carbon dioxide (CO2) constitutes 80% of current GHG emissions
(Lashof and Ahuja, 1990)
INTRODUCTION
 Agricultural activity contributes to CO2 emissions due to:
11. fuel consumption (farm machinery and field operations;
irrigation)
22. fertilizer and pesticide usage (herbicides,
(herbicides insecticides,
insecticides
fungicides)
CROP PRODUCTION BUDGET
 Previous studies depended on crop production budget from state
extension services
 Providing a planning tool to generate farming costs and returns
 Advantage - being convenient
 Disadvantage - not intended to represent "real" farm operations
METHODS
 Sample of farming operations across a multiyear period from 2005 to 2010
 Data source: Texas Alliance for Water Conservation (TAWC)
p
diesel, nitrogen,
g pphosphorous,
p
herbicides, insecticides and water
 Inputs:
 Crop: irrigated cotton
CARBON EQUIVALENTS
 Each input on each farm in each year was converted to an estimated carbon
emissions equivalent
 Carbon equivalents, or pounds of carbon emitted per unit of input per acre,
were applied to the gross quantity of each input
 The resulting value specified the total carbon emitted per acre
CARBON EQUIVALENTS
Input
Carbon-equivalent
Diesel
6.1 lbs C/gallon
Nitrogen
1.3 lbs C/lb
Phosphorous
0.2 lbs C/lb
Herbicide
6.3 lbs C/lb
Insecticide
5.1 lbs C/lb
Water
11.7 lbs CO2/acre-inch
AVERAGE CARBON EMISSIONS PER ACRE
Year
Diesel
Nitrogen
Phosphoro
us
2005
22.84
125.38
6.28
27.09
1.51
103.93
287.03
2006
21 35
21.35
122 51
122.51
2 34
2.34
30 28
30.28
0 27
0.27
180 09
180.09
356 85
356.85
2007
21.33
123.37
4.53
23.01
3.28
140.67
316.19
2008
18.97
109.80
6.56
12.04
0.18
126.67
274.22
2009
12.36
129.79
4.79
15.03
0.36
148.01
310.34
2010
27.66
153.92
7.96
13.13
1.21
86.49
290.36
Average
20.75
127.46
5.41
20.10
1.14
130.97
305.83
Herbicide
Insecticide
Water
Total
STATISTICAL ANALYSIS
 EasyFit Program - examines a variety of probability density
functions (pdf) choosing the function that best fits the data
 Statistical Analysis System (SAS) – calculation of the 95%
quantiles
il based
b d on the
h estimated
i
d pdf
df for
f iirrigated
i
d cotton
GOODNESS-OF-FIT
GOODNESS
OF FIT TESTS
All indicated that the lognormal distribution was appropriate
Test
Statistic
p Value
Kolmogorov-Smirnov
D
0.06149205 Pr > D
0.187
Cramer-von Mises
W-Sq
0.09260494 Pr > W-Sq
0.072
Anderson-Darling
A-Sq
0 68912708 Pr > A-Sq
0.68912708
0 025
0.025
PROBABILITY DENSITY FUNCTION
95% CONFIDENCE LIMIT QUANTILES
Lower bound
Upper bound
(lbs. C/acre)
166.56
(lbs. C/acre)
533.52
 Budgeted amount (547.06
(547 06 lbs.
lbs C/acre) was 77% higher than the mean
(309.39 lbs. C/acre)
 Less than 5% p
probabilityy that the budgeted
g
value for carbon emissions
is representative of the carbon emissions from the sample of farms
CONCLUSION
 Carbon emissions from 62 cotton production sites are significantly
lower than extension budget value
 Farms used are not a representative sample of farms in the Texas
Plains
 St
Study
d raises
i a valid
lid question
ti as to
t the
th accuracy off the
th carbon
b
emissions estimates for cotton production
 Carbon emissions as a public and policy concern
 Reliable information about carbon emissions is important
ACKNOWLEDGMENTS
 The authors thank the Cotton Incorporated Texas State Support Committee
for financial support of this project and Don Ethridge for his reviews of the
paper