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5. Future Directions and Outlook
To assess the rate of change in recent years, trend analysis was carried out for the different
regions. To minimise the difficulties caused by the annual fluctuations within the limited data
available, the analysis was carried out to assess the trends in the proportion of the area of
winter crops sown to cereals, rather than to broadleaf crops3. Broadleaf crops are then the
difference between these figures and 100%.
A log-linear trend line was fitted to the data for each region in the form:
log Cn = a + b n,
where Cn is the percentage of cereals in year n, b is the annual rate of growth in C, and n is the
year. In this form, the parameter b defines the annual proportional rate of growth in the
relative importance of cereal crops.
The results are shown for the percentage area sown to cereals for each of the regions and for
NSW as a whole for the period 1993-2003 (Table 6). Because of the variability in the data,
particularly in relation to the recent drought, and the limited number of years for which
consistent data are available at the regional level, there are relatively large errors associated
with these trends estimates. However, they indicate the direction of change and the relative of
the rates of change in the mix between cereals and broadleaf crops for different regions.
Table 6: Rate of Change in Proportion of Area Sown to Cereals, and Projected Levels
|
Annual rate |
______% crop area sown to cereals_______ | |||
|
Actual |
Projected _______2010 |
Projected 2020 | ||
|
North-east |
-0.12% |
88% |
88% |
86% |
|
North-west |
-0.65% |
88% |
77% |
66% |
|
- Total North |
-0.41% |
88% |
82% |
75% |
|
South-east |
-0.24% |
77% |
76% |
72% |
|
South-west |
-0.08% |
91% |
92% |
90% |
|
- Total South |
-0.18% |
85% |
84% |
80% |
|
NSW Total |
-0.27% |
86% |
83% |
78% |
3 Over the period 1993-2003, the mean of the cereal percentages ranged from 81% to 94% for the different
regions, with a standard deviation of between 2% and 5%. The alternative measure of the percentage of
broadleaf crops, therefore, had means from 6% to 19%, and standard deviations of 2% to 5%. Thus the relative
variability was considerably lower for cereals, and it was therefore more convenient to apply the trend analysis
to the percentage of cereals.