FACTORS A FFECTING A DOPTION OF C OVER C ROPS
AND I TS E FFECT ON N ITROGEN U SAGE AMONG US
FARMERS
O UTLINE

Introduction

Literature Review

Data

Methodology

Results

Conclusion
I NTRODUCTION

Changing environmental concern

Changing agricultural practices

Multifunctional agriculture
- besides providing traditional
products, agriculture provides
many public goods and services
I NTRODUCTION

Technology adoption

Water conservation and organic
production practices

Cover Cropping

Increased yield

Decrease Nitrogen (N) leakage
L ITERATURE R EVIEW

Olaf Erenstein (2003) and Ngouajio et al. (2002)


U.M. Sainju et al (2002) and Larson et al. (2001)


Cover crops help increase soil fertility and weed
management constraints
Use of cover crops can provide N to the next crop,
conserve N concentration through mineralization and
erosion, and reduce nitrogen fertilizer requirements
Tonitto et al. (2005)

Nitrate leaching was reduced by 40% in legumebased systems
O BJECTIVE

Identify determinants of cover crop adoption.

Understand the change in the probability of
adoption of cover crops by demographic, socioeconomic, and agronomic characteristics.

Analyze how N management varies by farm
relative to adoption or non-adoption of this
technology.

Estimate the change in N use for those who
adopted and didn’t adopt cover crops by
demographic, socio-economic, and agronomic
characteristics.
D ATA

The survey conducted in 2009 with collaborators
from 6 universities (NSF funded Project)

7 states in MRB – IL, IN, IA, OH, MI, MN, and WI

2 ERS regions (Northern Crescent – IL, IN, IA, OH;
and Heartland – MI, MN, and WI)

233 organic & 212 conventional farmers

Data for 2008 production year

Organic farmers only in this analysis
D ATA
Variables

Demographic – ERS region, age, farm income,
education, experience;

Socioeconomic - farm size, proportion of rented
land, livestock, rented/not, cover crops, and
information sources for N decision making – other
farmers who adapted cover crops, other farmers
relying on commercial N, organizations promoting
cover crops, and organic fertilizer dealers;

Agronomic – all CRP payments, slope (more than
6%), no till used, rotation with winter cover crops,
tile drainage,
M ETHODOLOGY
Two-Stage model
6) Test of Endogeneity using Smith
Blundell (1986) two-step procedure
R ESULTS
Estimation Results from Probit Model (first stage)
Cover_crop
Coefficient
Standard Error
Marginal Effect
Op. age**
0.038486
0.01888
0.015301
Farm size (acres)
0.000367
0.000148
0.000146
Total farm inc. (in
$100,000) **
-0.12938
0.053405
-0.05144
Op. education
-0.07002
0.136631
-0.02784
Years of experience**
-0.1314
0.053542
-0.05224
Expsq**
0.00226
0.001036
0.000899
Share of rented field
-0.11276
0.114789
-0.04483
Region (Northern
Crescent )
-0.42167
0.267113
-0.16671
Isds_cov*
0.232812
0.131134
0.092562
Isds_org
0.114494
0.116085
0.045521
Isds_ode*
-0.21059
0.115494
-0.08373
All conservative
payments*
0.54105
0.328359
0.209468
Slope
-0.41399
0.355918
-0.1637
_cons
-0.66191
1.19023
* - 10% significance, ** - 5% significance
R ESULTS
Estimation Results from Tobit Model (second stage)
Marginal Effects
Nitrogen
Coefficient
Standard
Error
Predicted values of
cover crop**
-168.504
79.5384
-0.45787
-68.1958
-96.3545
Op.’s education
-24.1739
16.33009
-0.06569
-9.78348
-13.8232
Farm size (acres)
0.010749
0.008847
0.00003
0.00435
0.006147
Total farm inc. (in
$100,000) *
-6.16218
3.769868
-0.01674
-2.49391
-3.52367
Livestock*
56.18214
33.73149
0.153574
21.60315
30.12598
No-till used
248.0961
177.8572
0.421492
154.1898
200.1675
Tile drainage
-41.0329
32.15755
-0.11175
-16.2936
-22.9094
Slope
-44.1224
48.14568
-0.12105
-16.806
-23.4059
Rented**
-75.7667
32.14944
-0.20624
-28.9987
-40.3042
Rotation with winter
cover crops**
86.94256
41.66603
0.225794
38.07737
53.90144
Isds_com
-7.76554
14.87927
-0.0211
-3.14282
-4.44051
_cons
168.9228
90.32249
* - 10% significance, ** - 5% significance
Probability
(%)
Adopters
Nonadopters
C ONCLUSION

Farmers’ age (+) and experience (-) had significants
effect on cover crop adoption.

Conservation payments positively affected the
adoption of cover crops.

Interacting with other farmers who were using cover
crops increased the probability of adoption, but
organic fertilizer dealers had negative effect on
adoption.

If the field is rented then the nitrogen use decreased
by 29 and for adopters and 40 pounds/acre nonadopters.

Cover crop adoption significantly decreased nitrogen
use by farmers (68 and 96 pounds/acre for adopters
and non-adopters respectively)
T HANK Y OU
Questions/Comments ? ? ?