Archive for March, 2014

Sustainable farming – what is it?

Wednesday, March 19th, 2014

Yesterday as a guest of Trevor and Anne-Marie Mills and the Western Port Catchment Landcare Network I attended a field day on the Mills’ dairy farm at Drouin South.

Amongst the principles of sustainable agriculture are that farming should:

– provide an amenable lifestyle for the farmer & family

– protect and enhance the productive capacity of the farm

– protect and nurture the natural environment and reduce environmental impacts

Judging by these criteria, the Mills have gone a long way to creating a sustainable farm. Much of this has been achieved by thinking ‘outside the square’ and often going against conventional thinking. For example T & A-M have fenced off and replanted many of the drainage areas and watercourses on the farm. Water is now piped to stock high up in each paddock. The result; less contamination of water, less nutrient runoff and cleaner water for the cows to drink.

The South Gippsland area was originally heavily forested and early accounts have detailed the diversity of wildlife that once existed. Now with areas on the farm returning to natural vegetation, some of the native animals are also returning. Happily these areas are often those that would be less productive and difficult to manage. The photos below taken from the same spot approx 5 years apart show the dramatic change around a natural waterway.

Before and after watercourse revegetation on the Mills Farm at Drouin South. By excluding stock from wet gullies significant improvements have been made to the quality of water flowing from the farm and as drinking water for stock. Approx 5 years between photos. Courtesy of T & A-M Mills and WPCLN.

Before and after watercourse revegetation on the Mills Farm at Drouin South. By excluding stock from wet gullies significant improvements have been made to the quality of water flowing from the farm and as drinking water for stock. Approx 5 years between photos. Courtesy of T & A-M Mills and WPCLN.

The WPCLN as part of their involvment in the property have been monitoring water quality and this has provided valuable feedback for farm planning.

On the farm management side T & A-M have adopted a rotational grazing system that takes advantage of the natural productivity of the soil and facilitates nutrient cycling whilst protecting against overgrazing and damage to pasture. The result, an increase in productivity which has meant that the herd size can be reduced whilst maintaining production.

I was especially interested to hear how Trevor had cut back on use of urea as a nitrogen fertilizer. This came about because he saw that the urea was favouring grass growth and supressing clovers. Now clovers are thriving and producing nitrogen naturally!

I think that soil testing still has a role to play on this farm. Particularly if it is done in a way that provides a better understanding of management effects on soil processes and the dynamics of nutrient movement around the property as well as off the property as natural losses and in farm products.

Judging by the attendance at the field day there is a lot of interest in sustainable farming and land management. The Mills farm is an excellent example for all to see that shows how productive farming can go hand in hand with protecting and enhancing environmental quality.

How can I improve the pasture on my farm?

Tuesday, March 11th, 2014

A complete soil test is an important first step to help restore the productivity of pastures. Most soil tests provide a breakdown of major and minor plant nutrients but many also profile the soil’s overall health, potential and fertility.

I was recently asked to visit a property in Gembrook east of Melbourne that was used to run horses. This was in February and the soil was very dry, around 3% moisture. At this level most biological activity in the soil ceases (more about this later). Now no-one expects a farm to be at its most productive during summer but its a good time to check on how well the soil and pasture is standing up to the stress of summer. Good indicators are the amount / proportion of bare ground, if there is any useable pasture left standing and the presence of weeds. Unfortunately this property showed signs of stress with little standing feed for the horses.

Horse paddock in Gembrook. A complete soil test is the first step towards re-establishing a good feed base for horses.

Horse paddock in Gembrook. A complete soil test is the first step towards re-establishing a good feed base for horses.

This is a higher rainfall area and soils are highly oxidized hence the red iron colour common in the area. On the positive side these soils have a good structure and are well aerated but they tend to be acidic and this is difficult for most plants.

Some results:

Test measured preferred comments
pH in water 5.83 6 – 7 too acidic
pH in CaCl2 5.04 5.4 – 6.4 too acidic
Bulk density 0.89 ‘light’ soil
Soil water 3.1% around 20% very dry

The soil is acidic as expected.  The bulk density value shows that the soil is lightly textured and because the soil felt soft this suggests that there may be organic materials in the soil and the soil may be well aerated. By contrast some soils in West Gippsland have a heavy consistency like butter and when dried lose their structure and become powdery.

How much organic matter was in the soil?

Test measured preferred comments
Total organic C 37184 ppm 29000 – 52000 moderate
Fresh organic C 466.5 ppm 860 – 2100 very low
Proportion fresh org C 1.23% 2.9 – 3.9% low

The soil had moderate levels of organic matter but most is ‘older’ humic type organic matter. There is not much fresh organic matter present. Overall the picture is of little recent return of plant material to the soil. Is this important? Yes, because organic matter has a significant role in making nutrients such as phosphorus and sulphur available to plants – a very important role in these types of soils. Check my previous blog entries for some results and comments for dairy farm soils.

Complete soil tests are a cost effective management tool. Tests that cover all nutrients, many of the main physical factors and organic matter levels cost around AU$150. In future blog entries I will cover more of the test results from this Gembrook soil.