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Dealing with salinity in Wheatbelt Valleys - Department of Water

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Lloyd<br />

0<br />

-500<br />

-1000<br />

-1500<br />

-2000<br />

-2500<br />

Jan-97<br />

Mar-97<br />

May-97<br />

Jul-97<br />

Sep-97<br />

Figure 1 shows the relationship between two<br />

bores <strong>in</strong> the same area. Prior to August 1997,<br />

both bores were surrounded by annual (sparse<br />

barley grass) pasture. There was a difference <strong>of</strong><br />

approximately 30 cm <strong>in</strong> the water levels between<br />

the two bores. Saltbush was seeded around bore<br />

8 <strong>in</strong> August 1997. With<strong>in</strong> twelve months the<br />

relationship had changed <strong>with</strong> the water <strong>in</strong> bore 8<br />

now lower than bore 9. This <strong>in</strong>creased <strong>with</strong> the<br />

onset <strong>of</strong> summer, until a difference <strong>of</strong> 70 cm<br />

between the two bores was observed – a total<br />

turnaround <strong>of</strong> 1 m. In August 1999, saltbush was<br />

Nov-97<br />

Jan-98<br />

Mar-98<br />

May-98<br />

Jul-98<br />

Sep-98<br />

"Bundilla" Bore 10<br />

Nov-98<br />

Jan-99<br />

Figure 2: Effect <strong>of</strong> saltbush on the watertable at bore 10.<br />

Mar-99<br />

May-99<br />

Jul-99<br />

Sep-99<br />

Nov-99<br />

Jan-00<br />

Mar-00<br />

May-00<br />

seeded around bore 9 and now the orig<strong>in</strong>al<br />

differences observed prior to plant<strong>in</strong>g saltbush at<br />

either site are evident. However, s<strong>in</strong>ce March<br />

2001, both these bores have been dry.<br />

Figure 2 shows the effect <strong>of</strong> saltbush on the<br />

watertable at bore 10. Saltbush was planted<br />

around this bore <strong>in</strong> August 1999. In the 13 months<br />

to the end <strong>of</strong> January 2000, Bundilla recorded<br />

twice its annual ra<strong>in</strong>fall, culm<strong>in</strong>at<strong>in</strong>g <strong>in</strong> the area<br />

be<strong>in</strong>g flooded <strong>in</strong> late January 2000. The watertable<br />

is now the lowest it has ever been, and <strong>in</strong> fact, for<br />

the last 6 months the hole has been dry at 2.3 m.<br />

Table 1: Differences <strong>in</strong> wool value from sheep grazed for longer on saltland pastures<br />

Mob Wool cut Micron Yield Price Value per head<br />

A 6.5Kg/hd 22.7 64.8% 375c/Kg $24.38<br />

B 6.5kg/hd 22.7 58.9% 342c/Kg $23.59<br />

Table 1 shows the difference <strong>in</strong> wool value from<br />

sheep grazed for longer on saltland pastures. Mob<br />

A grazed saltland pastures for 4 months from<br />

December to March follow<strong>in</strong>g 8 months (April to<br />

November) on annual pastures.<br />

– 4 –<br />

Mob B grazed saltland pastures only <strong>in</strong> December,<br />

be<strong>in</strong>g on annual pastures for the rest <strong>of</strong> the year.<br />

Both mobs were shorn <strong>in</strong> April. In addition, Mob<br />

B had supplementation <strong>of</strong> approximately $2.00 per<br />

head <strong>of</strong> lup<strong>in</strong>s <strong>in</strong> February and March.<br />

Jul-00<br />

Sep-00<br />

Nov-00<br />

Jan-01

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