An Economic Assessment of Banana Genetic Improvement and ...

SOCIAL CAPITAL AND SOIL FERTILITY MANAGEMENT IN UGANDA 101
Table 7.3 (continued)
Probit model:
Manure
Probit model:
Mulch
Second step of
Heck man model:
Manure
Ordinary least
squares model:
Mulch
Variable
Marginal
effects
Standard
error
Marginal
effects
Standard
error
Coefficient
Standard
error
Coefficient
Standard
error
Observed probability 0.416 0.690
Predicted probability at mean 0.399 0.785
Correctly classified 79.2 78.1
Likelihood ratio χ 2 (25) 124.24 = 120.18 =
Probability > χ 2 0 = 0 =
Log likelihood –163.26 –145.518
Pseudo R 2 0.2756 = 0.2922 =
Note: ***, **, and * indicate statistically significant differences at the 1, 5, and 10 percent levels, respectively.
findings from other studies that slope is
positively associated with perceptions about
soil fertility problem, which in turn encourages
use of soil fertility management practices
(Ervin and Ervin 1982; Shiferaw and
Holden 1998; Mwakubo et al. 2004).
One explanation for this finding relates
to the properties of the technologies. Although
erosion potential may encourage the
use of erosion control technologies, such as
conservation structures, it may act against
the use of technologies whose benefits are
likely to be lost when erosion potential is
high. Such is the case with manure in banana
production. On high slopes, the water
runoff can easily wash manure out of the
plantation, reducing its benefits. The capacity
of the soil to retain moisture is a statistically
significant factor only in the probability
of using mulching practices. The negative
sign can be interpreted in the same way as
in the case of slope with manure. Benefits
of incurring the high costs of mulching may
be low when the capacity of the soil to retain
moisture is low. Combined, the two
results suggest a “Malthusian scenario” that
people may perceive a soil fertility problem
but do nothing about it. Poor drainage conditions
of the soil affect only the probability
of applying manure. Again, the positive association
between poor drainage conditions
and probability of using manure lends itself
to the same explanation given for the findings
regarding slope. Poor drainage conditions
in the banana plots can also act
through disease risk, because manure—and
hence good plant nutrition—increases plant
vigor that enhances tolerance to leaf spot
diseases.
Most of the household characteristics
(demographic factors, education, and
wealth assets) were significant in the management
decisions. As expected, education
has a positive effect, reflecting the high
degree of knowledge that these soil fertility
management practices require. Other studies
have also found a positive association
between education and adoption of soil
conservation technology (Ervin and Ervin
1982; Mwakubo et al. 2004). Endowment
of wealth assets is equally important in
decisions regarding use of soil fertility
management practices. Ownership of livestock
may reduce the cost of using manure,
hence the positive effect of this parameter.
Estimated effects of the per capita size of
cultivatable landholding (adjusted for area
in swamps and water bodies) have a posi-