sustainability - SUNY College of Environmental Science and Forestry

Sustainability 2011 , 3 2382

Table 14. Percentage changes in the largest inputs per hectare to wheat and rice, 1999 to 2009.

FY

Wheat Rice

N fertilizer Output N fertilizer TW diesel Insecticide Output

1999

2000 2.7 14.8 1.8 12.0 29.3 6.3

2001 5.7 −6.6 8.1 8.6 −17.8 −1.3

2002 2.5 −2.7 13.4 8.4 65.1 −10.2

2003 3.1 5.6 −2.3 10.0 6.2 9.6

2004 5.2 −0.6 −2.7 25.9 50.0 −2.2

2005 19.9 9.0 20.5 2.8 −20.8 1.3

2006 3.5 −2.6 0.6 1.7 −60.2 6.0

2007 −10.8 7.8 −8.1 −10.2 119.7 −0.3

2008 10.7 −9.7 13.3 −5.6 −57.3 5.2

2009 −1.9 8.4 −11.9 −3.7 −15.1 6.5

The relationship between all per-hectare inputs and per-hectare output also shows some interesting
patterns. The 11-year dataset shows that wheat yield is still increasing with rising inputs. Rice,
however, shows a gradually declining trend (Figure 6).

Figure 6. Relation between energy inputs and output for wheat and rice crops in Pakistan

from 1999 to 2009.

For wheat per-hectare input against per-hectare output, the linear, quadratic, and quartic regressions
were significant (Table 15). None of the regressions were significant in the case of rice (Table 16).

0

5

10

15

20

25

30

35

40

45

Per-ha output of wheat and rice (GJ/ha) 0246810121416

Per-ha inputs to wheat and rice (GJ/ha)

Wheat

Rice

G