Euroa MLA Producer Demonstration Site – Soil Results

Over the duration of the project, soil samples were taken in autumn each year from the Euroa site, Longwood site (2009-2011) and the Longwood control paddock (2009-2011). The first test was taken prior to establishment in 2009. Results are presented in Table 1. Resulting fertiliser inputs are provided in Table 2.

Table 1. Soil Test Results 2009-2012, Longwood and Euroa

Test

Unit

Long-wood  2009

Long-wood 2010

Long-wood Control 2010

Long-wood  2011

Long-wood Laneway 2011

Long-wood Control 2011

Euroa 2009

Euroa 2010

Euroa 2011

Euroa 2012

Soil Texture

Clay Loam

pH (CaCl)

4.8

4.8

4.2

5.1

4.9

4.5

4.7

4.6

4.9

4.8

Organic Carbon %

2.3

2.2

2.3

3

2.8

3.5

2.2

2.2

2.3

2.3

Phosphorus Buffering Index

110

90

86

120

110

130

85

72

77

92

Olsen Phosphorus mg / kg

11

12

8

18

17

9

27

32

42

38.1

Nitrate Nitrogen mg / kg

25

41

14

13

19

4.5

28

25

10

9.5

Sulphate Sulphur mg / kg

14

20

7.7

15

12

5.1

56

32

12

11

Potassium mg / kg

160

150

130

140

160

180

130

120

160

150

Aluminium meq / 100g

0.37 (5.5%)

0.17 (2.6%)

0.83 (17%)

0.10 (1.3%)

0.10 (1.5%)

0.52 (9.5%)

0.33 (4.5%)

0.26 (5%)

0.11 (2%)

0.2

Table 2. Fertiliser inputs, Euroa Producer Demonstration Site

Site Year Fertiliser
Euroa plots 2009 100 kg/ha MAP
2010 50 kg/ha MAPTest strips for potash and single super/molybdenum
2011 100 kg/ha Urea
Longwood plots 2009 100 kg/ha MAP
2010 100 kg/ha MAP
2011 100 kg/ha MAP70 kg/ha Urea
Chicory 2009 100 kg/ha MAP
2010 100 kg/ha MAP
2011 100 kg/ha MAP
Ryecorn 2009 100 kg/ha MAP
Control 2009-2011 No fertiliser application

Phosphorus

The 100 kg/ha MAP applied at sowing (Table 4) increased phosphorus levels at both sites.

At Longwood, the 2010 results indicated that Olsen phosphorus (P) was yet to reach target levels (15-18 mg/kg) for optimum production (Gourley et al., 2007). A further 100 kg/ha MAP was therefore applied in 2010, and subsequently in 2011, after which target levels were reached at 18 mg/kg (Table 1).

Olsen P levels were very high at Euroa so only 50 kg/ha MAP was applied in 2010. An even higher level in 2011 meant there was no need for phosphorus that year.

Test strips showed no response

The 2011 soil test identified potassium as the limiting nutrient and a potash strip was set up to determine whether it would be worthwhile to apply potash in 2011. The site also had no history of molybdenum, so a superphosphate/molybdenum mix was put out in another strip. There was no visual response to either of the test strips.

Waterlogging had no impact on nutrient levels

In the spring of 2010, water logging occurred on some of the plots at the Longwood site, therefore in 2011, an additional soil test was taken to see if the water logging had any effect on the soil. There was no obvious difference between the soil tests.

Reduction in nitrogen – a cause for low cattle performance?

Urea was applied in mid-winter 2011 when nitrogen levels at both sites had dropped (Table 1); there were obvious nitrogen patches in the pastures; and cattle performance had significantly dropped with weaners losing or just maintaining weight, despite adequate feed availability.

It is likely that the low nitrogen levels were a result of leaching through the previous wet summer, combined with low clover availability, and therefore lack of nitrogen fixation. The cattle performance dramatically improved soon after nitrogen application, probably due to an increase in protein availability, combined with increased food on offer (See Section 5.8.1).

It is very hard to try to determine an ideal soil nitrate level as it can fluctuate widely during the season, depending on the nitrogen source, temperature, rainfall and plant use etc, and while some agronomists suggest that a level above 10 mg/kg is desirable for pastures, this is debatable.

Seasonal conditions effected sulphur levels

The drop in sulphur observed at Euroa in 2011 was likely associated with the wet summers that occurred in 2010 and 2011, combined with very little sulphur applied in fertiliser since the start of the demonstration (MAP has 2% sulphur). Increased use of high analysis fertilisers followed by wet conditions have contributed to a large number of soil samples showing a reduction and/or deficiency in sulphur levels (Menhenett, 2011). Sulphur is essential for nitrogen fixation by legumes, therefore very important to pasture performance.

As Euroa had a level above the recommend level of 8mg/kg, sulphur was not applied, but would be monitored and addressed in the future if needed.

More stable nutrient levels in 2012

The Euroa 2012 test indicated no dramatic reduction in nutrient levels. The Olsen P was still quite high for a grazing system and no fertiliser was applied. Sulphur levels had dropped again and it was recommended that single superphosphate was needed in the near future.

Acknowledgements

Thanks to the site hosts Andrew and Caroline Walta and John and Mary Kelly for hosting the sites, managing the cattle movements, recording weights, rainfall, grazing data and above all their commitment and passion to this project. Thanks also to the members of the Euroa Grazing Group – the project would not have been such a success without the drive and enthusiasm of the group.

This project was funded by Meat and Livestock Australia (MLA) and the Agriculture Victoria as part of the MLA Producer Demonstration Site initiative. Significant linkages were made to the BESTWOOL-BESTLAMB and EverGraze project to boost extension for the project.  Smyth Seeds and Stephens Pasture Seeds provided seed for the trial sites.

Demonstration and Case Studies

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