Summer Pasture Cropping and Soil Health Demonstration Site

Year of study:

2008-09

Lead organisation & collaborators (if any):

Sonia Lee (of Vital Farms), on behalf of the Bass Coast Landcare Network

Bass Coast Landcare Network

CFoC

Craig & Stuart Matthews

Colin Seis (Advanced Pasture Cropping Company)

Mapleton Agri Biotech (TwinN)

Bass Coast Seed Supplies

Contact:

Sonia Lee Vital Farms

T: 0411 843 128

 

Trial Site Details:

Dec 2008- Sept 2009 (10 months)

Unusually low rainfall throughout the growing period.  January & February received 23mm compared to the long-term average of 94mm over these two months. To offset this, a small area of the site was irrigated. 930mm

Brown dermosol

Upper slope (2 hectares)

Project details

Objectives:

The aim of the demonstration site was to investigate alternative soil and crop management practices suitable for dairy farms in West Gippsland in order to address issues of:

  • Degrading soil and pasture health leading to the need for conventional pasture renovation
  • Soil degradation and nutrient-leaching issues associated with meeting summer feed gaps using traditional cultivation-based cropping practices
  • High nitrogen inputs

It was hoped that methods could be demonstrated that addressed summer feed gaps while simultaneously improving soil health, pasture composition and reducing nitrogenous input requirements.

Basis of trial:

Adapting a variant of practice (summer pasture cropping) that has been applied elsewhere. Winter pasture cropping is established practice in parts of Gippsland region

Farm details

Pre-trail management:

Dairy cattle, rotational grazing

Typical dairy-farm applications of NPKS.

Trial Management:

One or two grazings of the pasture-crop were planned, but this did not eventuate (even on the irrigated portion of the site) as the crop did very poorly due to over-competition from the existing pasture base (predominantly ryegrass). Once these pasture cropping outcomes became evident, the site was rotationally grazed as per normal procedure on the dairy farm.

Methods and Measures

Trial design/layout:

This was a demonstration site rather than a scientific trial. No plots, one single 2 ha paddock on-which the Pasture Cropping technique & TwinN was applied.

 

Summary of key messages/findings of trial:

The crop result was extremely poor. This was partly an outcome of unusually low rainfall through January and February, however a portion of the site was irrigated and whilst the response was better in this portion, ryegrass and weed competition were strong and the crop was unable to compete.

It was concluded that there is no natural fit for summer pasture cropping techniques in West Gippsland due to unsuitable temperature range, rainfall & pasture base.

The success of pasture cropping in other regions of Australia is dependent on temperature & rainfall ranges that suit the interplay between C3 & C4 species during summer & winter.

West Gippsland temperatures do not hold consistently above 25 degrees Celsius during summer. This gives little competitive advantage for C4 over C3 species. Furthermore, rainfall during summer is often insufficient for C4 cereal crops. Perennial ryegrass is the predominant pasture species and, in absence of consistently higher temperatures, is highly competitive with C4 annual cereals. Hence, even in years of sufficient rain (or with addition of irrigation) lack of consistently high temperatures precludes pasture cropping success.

Methods

Fertiliser application during pasture cropping phase Fertilisers were applied to the pasture cropping phase but this was not a test or demonstration of these fertilisers as such but an integral part of pasture-cropping procedure. Requirements were calculated using a soil test. Growth elements applied at sowing and after sowing. Mix of urea, DAP, guano, Granam (Ammonia sulphate), copper sulphate, zinc sulphate and sodium molybdate.

Inoculation with diazotrophs After the pasture cropping phase, the site was inoculated with nitrogen-fixing microbes (diazotrophs) using the product, TwinN. Application date: May 1, 2009

A mix of summer-growing, annual and perennial forage species was direct drilled using pasture cropping techniques into the two-hectare perennial pasture. Sowing date: 27th December 2008

Seed Mix

Millet (Shirohie)                       6 kg/ha

Cow Peas (Caloona)    8 kg/ha

Chicory (Puna)             2 kg/ha

Plantain (Tonic)                      2 kg/ha

White Clover                2 kg/ha

Red Clover                   2 kg/ha

All legumes were inoculated.

Herbicide

Herbicide was applied three days prior to sowing at a rate calculated to shut down but not kill the existing pasture. The non-selective herbicide Gramoxone (paraquat) was used at 800ml per hectare.

Portion of the paddock irrigated to offset the drought conditions & allow some outcome from the demonstration.

Soil Sampling Method:

10 cm cores. 25 cores per treatment, bulked.

 

Production Measures

  • Extremely poor crop yield was visually obvious

 

Treatment results:

  • Post-cropping nitrogen deficiency in pasture, most likely due to the nutrient demands of millet.
  • Excellent response observed in clover, probably as a result of inoculation with diazotrophs (TwinN) – plant vigour & number, size, & colour of clover nodules increased dramatically from the baseline.Increased pasture species diversity due to over sowing: plantain, chicory & clovers.
  • Other measures of treatment responses were not specified.

Reporting:

How have these results been reported:

Technical report to Bass Coast Landcare Network

How can a copy of any relevant reports be obtained:

Sonia Lee of Vital Farms Pty Ltd, 0411 843 128

Level of review of results: not specified

Next steps

There is not the “natural fit” to support summer pasture cropping in West Gippsland.

There appears to be good potential for diazotroph inoculation (TwinN). Further replicated trial recommended.

Challenges/opportunities to apply trial results/findings

Replicated trials of TwinN & other diazotroph inoculants is recommended. Summer pasture cropping not worth pursuing in the region.