We live in a land where WATER is usually the most limiting factor. Our enterprise is beef cattle breeding, fattening, backgrounding, & trading. Part of our herd is certified organic & part not certified. All stock are managed under organic principals. Our rainfall here is average 700 mm per year & ranges from around 300 mm up to 1400 mm. How does one manage livestock production in this variable environment?
We use a few “base” rules:
We rest our pastures after grazing. This is done through using a “cell” grazing system. In short we have 100 paddocks, in which we run from two to three herds of cattle. We “shoot” for 60 days rest at start of growing season (summer) allowing grass plants to establish good deep root systems. trials in South Africa demonstrated that grass rested for 60 days gets roots down 120 cms, while unrested grass only has roots down to 30 cms.
We like to have a diverse sward of PERENNIAL grasses. Trials in West Australia demonstrated that with perennial grass rainfall infiltration rate can be up to 175 mm per hour, while with litter cover infiltration is 45 mmm per hour, & bare ground is 25 mm per hour. On day two infiltration rate went up to 300 mm per hour on perennial grass, while litter reduced to 30 mm, & bare ground to 12 mm. Yes infiltration rate almost doubled (175 mm to 300 mm)on second rainfall event, while on litter (45 mm to 30 mm) & bare ground (25 mm to 12 mm) it significantly reduced!
SOIL ORGANIC MATTER
SOIL ORGANIC MATTER & water holding capacity. We strive to always be increasing our soil organic matter levels. 100 kg of soil with 1.5% to 2% organic matter holds 45 litres of water, while with 4% to 5% holds 200 litres of water. 1 & 2 above help facilitate 3.
We aim to maintain a minimum of 1/3 of our landscape in trees. Eighteen years of grazing yield data from our whole farm demonstrates little gain in production from re-clearing trees from our landscape. We have now from this data shown that it will take 98 years to recoup the $’s we spent on re-clearing!!! Not a good return on investment. Having all the preparations out there is similar to having a full symphony orchestra playing!
What then do trees do in our landscape?
- Keep it warmer & cooler. A 4 degree reduction in maximum temps & a 4 degree rise in minimums where we have trees. This has led to a great reduction in frost damage to our pastures.
- Trees cycle nutrients from deep in the soil where grass roots do not go.
- Trees attract moisture due to their cooling effect. This action is similar to the condensation we see on the outside a glass of cold water.
- Trees reduce surface evaporation by up to 70%. Our annual average rainfall is 700 mm while surface evaporation is 2000 mm! Any reduction in surface evaporation is very valuable in aiding pasture growth.
We use the full set of biodynamic preparations across our landscape. Rather than using the preparations individually we use Biodynamic Soil Activator (a combination of all the Biodynamic preparations). Our belief is that nature can choose what preparations it wants to use & at what time!
In permaculture Mollison spoke of “maximum production being at the edge”, & designing a landscape to maximise edge effect. This we achieve through diversity. A diversity of grasses, legumes, forbs, shrubs, trees, & also a diversity of animals.
MATCH STOCKING RATE TO CARRYING CAPACITY
We continually monitor & adjust stocking rate according to rainfall. To do this we measure stock days per hectare per 100 mm of rain, having a benchmark which indicates whether we need to increase or reduce stock numbers.
The seven points above we regard as the base “rules” for maximising water use efficiency on our farm.
Using a combination of these key points has facilitated our landscape health improving steadily over the past 30 + years, & has delivered a more consistent PRODUCTION outcome in a highly variable rainfall.
Article courtesy of Shane Joyce