Agriculture Reference
In-Depth Information
In the Distribution Module, the most common power range (P
beginning,
m,y,
P
end,m,y
) of machinery is selected on the basis of experience and divided
into n intervals. The midpoint of interval i as its representative power p
i,m,y
can be obtained using the following relationship:
(5)
The total number of machinery L
m,y,c
and the total power P
m,y,c
can be
obtained from statistics, so another two equations can be established:
(6)
(7)
Equations (4)-(7) should be solved simultaneously to estimate param-
eters a
m,y
and b
m,y
. Then the number l
i,m,y
of the agricultural machinery (ex-
cluding tractors) with the representative power p
i,m,y
in the interval i can
be determined.
Tractors are the most common agricultural machinery and play an im-
portant role in mechanized agriculture in China. The number and total
power of tractors increased from 9.86 million and 1.08 × 10
8
kW in 1996
to 21.78 million and 2.84 × 10
8
kW in 2010, with annual increases of
5.82% and 7.16%, respectively. The rated power of the main tractor mod-
els in Chinese market is between 8 and 12 kW, while in China's Depart-
ment of Statistics, the rated power for tractors starts from 2.2 kW, so in
SECA, it is assumed that the number of large and medium-sized tractors,
referring to tractors with power ratings greater than or equal to 14.7 kW,
still follows an exponential distribution. On the other hand, the number of
small tractors, referring to tractors less than 14.7 kW and greater than 2.2
kW, follows a parabolic distribution [Figure 2(b)]:
