Surface drainage systems to reduce waterlogging of pastures

2007
CC BY 4.0

Research organisaton

Trial details

Researcher(s) Troy Jenkin
Tim Johnston
Graeme Ward
David Watson
Year(s) 2007
Contributor Southern Farming Systems
Trial location(s) Derrinallum, VIC
Surface drainage systems to reduce waterlogging of pastures locations
Aims

To investigate the effect of two different methods of surface drainage ('raised beds' and 'hump and hollows') of pasture compared to an undrained control treatment on farm productivity and the potential impact on the environment. 

Key messages

During 2006 and 2007, a field trial designed to quantify the effect of two different surface drainage strategies of pasture (hump & hollow and raised beds) on farm productivity, profitability and sustainability was conducted on a commercial farm near Derrinallum. Under the rainfall conditions experienced for the two years of the trial, it is concluded that the use of raised beds for the growing of pastures for grazing has little to offer the sheep industry. On the basis of the data obtained in this trial, it is recommended that the hump & hollow system is the preferred method of surface drainage for sheep grazing systems in this environment and should be promoted in the region. Major findings included:

  • In both years, total annual pasture dry matter (DM) yields from the raised bed treatment were substantially less than for the undrained and the hump & hollow treatments.
  • In the drought year of 2006 the raised bed treatment grew 37% (2.8 t DM/ha) less while the hump & hollow treatment grew only 7% (0.6 t DM/ha) less than the undrained (total of 7.6 t DM/ha).
  • In the higher rainfall 2007 year the raised bed treatment produced 15% (1.6 t DM/ha) less pasture than the undrained. In contrast, the hump & hollow grew 10% (1.1 t DM/ha) more than the undrained (total of 10.7 t DM/ha) in 2007.
  • The reasons for the lower than expected pasture yields on the raised beds are speculated to be a combination of low yields in the furrows, poorer plant establishment and density on the beds, and a reduction in the water holding capacity of the soil relative to the other treatments.
  • Soil physical health was however considerably better on the raised beds than the other treatments. Aeration porosities at field capacity in November 2007 were a very healthy 16.3% in the raised beds, a moderate 11.8% for the hump & hollow and a poor 7.0% for the undrained.
  • No significant differences in ewe or lamb weights at weaning were found between treatments in either year. This was most likely due to the set stocked sheep having pasture on offer in excess of requirements for most of the spring. In 2006 however, the raised beds were stocked at around 1 ewe/ha less due to the lower pasture growth rates.
  • From a catchment and general environmental health perspective, the water run‐off results raise some concerns about the environmental impact of growing and grazing pastures on raised beds.
  • The raised beds proved to be very effective in removing excess water from the pasture. Over 2007, the raised bed treatment (47.1 mm) had 170% more runoff water than the undrained (17.4 mm) while the hump & hollow (26.7 mm) had 53% more runoff.
  • Both drainage treatments had considerably higher concentrations of, and total loads of phosphorus (P) and nitrogen (N) in runoff water. Of particular concern were the losses of 0.5 and 0.4 kg P/ha for the raised bed and hump & hollow treatments respectively compared to 0.1 kg P/ha for the undrained in 2007. For N, corresponding losses were 6.3, 2.1 and 0.9 kg N/ha for the raised beds, hump & hollow and undrained respectively.
  • It is recommended that if raised beds are to be used for grazed pastures, then the best practice recommendations developed for raised bed cropping also be applied to pasture.
Lead research organisation N/A
Host research organisation N/A
Related program Grain & Graze
Acknowledgments

Thanks to Darren and Michelle Evans for supplying the land and Cam Nicholson (Grain & Graze).


Other trial partners Not specified
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Method

Crop type Weed: Ryegrass
Treatment type(s)
  • Adverse Effects Management: Waterlogging
  • Management systems: Soil engineering
Trial type Experimental
Trial design Unreplicated

Derrinallum 2007

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Other trial notes

Approximate location. Dave Watson

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Download results

Trial results Table 1

# Variety
Treatment 1
Dry matter (t/ha)
1 Crusader & Abundant (short term ryegrass) Undrained 10.65
2 Crusader & Abundant (short term ryegrass) Raised bed weighted (based on 1.7m width top of beds and 0.3m furrow width) 9.07
3 Crusader & Abundant (short term ryegrass) Raised bed tops 9.68
4 Crusader & Abundant (short term ryegrass) Raised bed furrows 4.61
5 Crusader & Abundant (short term ryegrass) Hump & hollow 11.71

Dry matter t/ha


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Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Derrinallum, VIC Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Derrinallum, VIC Sodosol
Soil Moisture Source: BOM/ANU
Average amount of water stored in the soil profile during the year, estimated by the OzWALD model-data fusion system.
Year Derrinallum VIC
2007 385.6mm
2006 385.1mm
2005 414.7mm
2004 428.1mm
2003 424.6mm
2002 416.3mm
2001 390.8mm
2000 343.0mm
National soil grid Source: CSIRO/TERN
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties

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Climate

Derived climate information

No observed climate data available for this trial.
Derived climate data is determined from trial site location and national weather sources.

Derrinallum VIC

NOTE: Exact trial site locality unknown - Climate data may not be accurate
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Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.

Trial report and links

2007 trial report



Trial last modified: 20-11-2019 09:14am AEST