WHEAT IN BANGLADESH: YIELD GROWTH, PRODUCTION PERFORMANCE AND DETERMINANTS - Soybean and Wheat Crops: Growth, Fertilization, and Yield - page 210

and

13

∑ =

u = δ + δ Z + ζ (6)

i 0 d id i

d 1

where Y i is the wheat output (including grain equivalent of straw output); X ij is j th input for
the i th farmer; E ik are the environmental production condition variables, R im is the dummy
variable for districts, v i is the two sided random error, u i is the one sided half-normal error, ln
natural logarithm, Z id variables representing managerial and socio-economic characteristics of
the farm to explain inefficiency, ζ i is the truncated random variable; α 0 , α j , β j , τ m , δ 0 , φ k and δ d
are the parameters to be estimated.
A total of five production inputs ( X ), seven environmental production condition variables
( E ), and two regional dummies ( R ) were used in the production function, and 13 variables
representing managerial and socio-economic characteristics of the farmer ( Z ) were included
in the inefficiency effects model as predictors of technical inefficiency. Table 2 presents the
definitions, units of measurement, and summary statistics for all the variables.
Table 2. Definition, measurement and summary statistics of the variables used in the
stochastic production frontier model

Variables Measure Mean Standard

deviation

Inputs and output

Wheat (includes
grain equivalent of
straw)

Kg per farm 655.5495 346.414

Land cultivated Hectare 0.13 0.06

Labour Persons 13.35 6.23

Fertilizers Kg of active nutrients (N, P, K, and S) 19.28 9.85

Draft/mechanical
Power

Taka 289.12 158.32

Irrigation Taka 22.25 8.15

Environmental
production
conditions

Land type

Indexed (1 = Medium high land - most
suitable; 2 = High land - suitable; 3 =
Low land - not suitable)

1.49 0.74

Soil type

Indexed (1 = loamy - good; 2 = sandy
loam - average; 3 = clay loam - poor)

1.86 0.71

Weed infestation a Indexed (1 = 1 - 10%, 2 = 11 - 20% of

crop yield)

0.73 0.53