CHANGING PRACTICES TO DEAL WITH RAINFALL VARIABILITY

Gunningrah. Read Charlie’s own experience of why and how he changed to regenerative farming practices and the wonderful outcomes the Maslins have achieved on their property.

PART ONE

CHANGES TO THE MANAGEMENT OF WATER ON GUNNINGRAH

The variability we face on our southern Monaro property is the factor which drove us to make substantial changes to the way we manage water. This applies to both the rain which falls, and the runoff which flows through our land.

The impact of rainfall, and the resulting season’s growth, has a great bearing on our cost of production, and as a result our profitability.

As an example, between two consecutive years, one with good rain and the next with very low recordings, our cost of production doubled for our sheep enterprise, and tripled for the cattle.

Our rainfall records go back to 1918, and a neighbour’s records back to the 1858. As the place where the neighbour’s records are taken is less than 2km from our boundary, I will use them for this exercise.

How variable is the rainfall?

In our area, the annual precipitation over the last 160 years has an average just over 600mm. The range within which the average comprises goes from a low of 250mm to a high of 1200mm.

It is this variability, both within and between years, which causes the problems for farmers planning ahead.

It is very hard to find either annual or monthly patterns. The standard deviations for all data, both monthly and yearly, is very high.

The number of years with rainfall falling within +\-10% of the average is only 33, or less than 20% of the 160 years recorded! The only thing which is noticeable about the data, is that the number of years with above average rainfall are half that of those with below average figures.

DSE* days / hectare / 100 mm of rain, and try to keep this figure in the 300 to 350 range. This enables us to better match the stocking rate with the carrying capacity of the land.

…and through water management

While run off events became rarer due to the grazing management changes, when at times it did happen, damage to streams still occurred. This was firstly, erosion in the stream bed, and secondly, sediment transfer downstream.

To overcome this, we also made changes within the streams on our property, to slow down the rate of flow during such heavy rainfall events.

Along the lines of the Natural Sequence Farming principles, we placed weirs in the upper sections of some streams, with the aim to slow the flow, trap the sediment, and improve the water quality.

The weirs were made from a variety of materials. Ranging from rocks and earth ( the majority ), and others out of old logs, old fence posts, old rolls of fencing materials… whatever suited the spot and was available.

The cost of doing these stream works was really very low. The first stream we tackled was not overly incised, and 20 structures were built at an average cost of just $200. These weirs were all earth and rock, built using an excavator.

Some of the later streams we worked on had much greater incisions, and while costs varied, some structures were up to around $1200, with an average cost of about $500 to $600.

Weir construction in 2006 (left) and the same gully showing significant improvement in 2008 (right).

While it is almost impossible to evaluate a cost / benefit value on the weirs, there are many observable benefits. For the grazing changes, there are observable benefits like the weirs, but also some very quantifiable advantages…

We hope you enjoyed reading Charlie’s story. Tune in next week when he’ll outline the many benefits and advantages he’s received as a result of adopting these regenerative practices.

The Soils for Life Team

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MANAGING WATERWAYS

Many of the Soils for Life case study participants are applying techniques which are based on the natural hydrology of the Australian landscape and how nature evolved and sustained immensely productive and resilient biosystems despite Australia being such a dry continent. By understanding these hydrological processes, resilient water systems can be designed and restored.

Restoring hydrological processes

Australia’s landscape used to be characterised by ‘in-soil’ reservoirs. Complex microbial ecologies maintained soft deep soils which allowed for infiltration and retention of rainfall into well-structured subsoils. These in-soil reservoirs then leached any salt to depth and slowly recharged and sustained what were typical reed covered billabongs, chains of ponds, meandering waterways and fully functioning floodplains. As a result, most of Australia’s inland rivers did not discharge rainfalls to the sea, but recharged aquifers or created highly productive inland deltas and extensive wetlands and intermittent lakes.

With the introduction of grazing across the Australian landscape, riverside vegetation was grazed and repeated stock access caused the banks to become eroded. Gradually, rainfall would wash into what was becoming a gully and only in significant rainfall events would it flow over the banks, each time washing away more soil. Confined to a gully, water flow continues to erode and gullies become more deeply incised.

A primary step by many of the case study participants in more effectively managing water on their property has been to fence off water courses to prevent stock access, or limit access through time-controlled planned grazing, to reduce further erosion of river banks. Combined with the establishment of leaky weirs, as drawn from Natural Sequence Farming methods, this enables regeneration of vegetation and restoration of riparian areas to function as they did prior to the introduction of grazing. Read more about how this works on the Earth Integral website.

Water management in action

On Tallawang on the NSW North West Slopes and Plains, Craig Carter was concerned about the poor condition of the land – erosion, soil compaction and impoverished pastures – and the severely eroded creek and gullies. The banks of the creek and tributaries were incised, with gullies and contour banks further draining water off the property, increasing susceptibility to drought. The creek had eroded down to a base of basalt rocks and stones for its length. Craig sought advice from Peter Andrews, to design leaky weirs to restore natural water cycles.

Mainly constructed from dead trees, later in conjunction with plantings of native reeds, these structures created a ponding effect and retarded water flow. Six years on, previously bare soils and gravel beds are covered with regenerating plants and considerable siltation is evident as the vegetation traps sediment carried from upstream. The creek on Tallawang is now a ‘chain of ponds’, and while inflow varies with rainfall, outflow is constant due to improved water retention in the soil and subsequent hydrological processes.

Left: The river on Tallawang used to be typified by an exposed basalt rock base.
Right: Downstream weirs have resulted in silt build-up and regeneration of vegetation along the banks

On Tallawang, existing contour banks in higher country were also modified, by blocking them at intervals, to form swales that retain and more effectively use water in the upper parts of the landscape. This process has enabled surface water to infiltrate higher in the landscape, thus maintaining the quality and quantity of the diverse perennial pastures longer in the drier times.

Similar techniques applied to the landscape in some of our other case studies include…

On Jillamatong NSW, Martin Royds has shallow drains radiating out from weirs to divert water from the waterway across the paddock.

As a result of the regenerative practices applied on Tallawang, the property has become significantly wetter along the upper and mid slopes with increased palatable vegetation later in the drier seasons. Wells that were empty on Craig’s arrival to the property are now full. Previously dry soils along the creek flats are now swampy meadows and wetland plants that did not exist on the property prior to the commencement of the work are in abundance.

Tallawang provides a great example of how rainfall can be made available to be used effectively where it falls, rather than being run off due to poor ground cover or eroded creek lines. Read more of Craig’s story in our Tallawang case study.

Next week we’re going to have the first of our guest blog posts by Charlie Maslin of Gunningrah , who has also achieved some amazing results on his property by actively managing to maximise his received rainfall.

Stay tuned.
The Soils for Life Team

MAXIMISING RAINFALL INFILTRATION FOR PRODUCTION

last week) and maximise rainfall infiltration and retention to support longer production times, Soils for Life case study participants have focused on improving soil structure and increasing vegetative cover.

Improved infiltration through grazing management

On a number of our case study grazing properties, time-controlled planned grazing has been implemented (many based on Allan Savory’s Holistic Management techniques). A key component of this form of grazing management is increased mob sizes. By using higher density stocking, regrowth of unpalatable mature grasses is knocked down and this, plus any other plant litter, is trampled into the soil enabling it to break down more rapidly. This strongly contributes to the generation of soil organic matter and ultimately soil organic carbon level improvements. (Remember1 gram of soil organic carbon can hold up to 8 grams of water!)

Planned grazing also provides sufficient rest and recovery for pastures and triggers succession from low order species to more palatable and productive plants, particularly perennial species, increasing ground cover.

It is these processes that give Shane and Shan Joyce of Dukes Plain in the Southern QLD Brigalow Belt and Charlie and Anne Maslin of Gunningrah on the NSW Southern Tablelands (amongst others), the capacity to manage production in periods of low rainfall. The improved soil structures and increased ground cover aid the:

  • infiltration, retention, availability and sustained supply of water from such soils;
  • aeration and capacity of roots to proliferate and penetrate deep into soils;
  • capacity for water to recharge and irrigate soils from below to limit loss due to evaporation; and
  • restoration of in-soil reservoirs and aquifer recharge.
The Joyces produce organic beef on Dukes Plain and manage their stock to
help improve their soil and pasture to maximise rainfall infiltration

The Joyces monitor post rain events to observe how deep moisture has penetrated and have found that rain infiltration in the soil has improved over the years since they implemented planned grazing. Rainfall events of less than 10mm were traditionally seen in the area as ineffective, however with the conditioned land and high levels of soil organic matter this moisture is now being absorbed into the Duke Plains soil. With around 70% of their rainfall events comprising less than 10mm rainfall, the Joyces are now able to harness this resource that previously had been lost.

Both the Joyces and the Maslins have increased production time on their properties, even with variable rainfalls, due to the improved hydrological function ensuring maximum infiltration and extending the growing season of pastures.

Reducing run off with humus-rich soils

Bill and Rhonda Daly’s mixed grazing/cropping enterprise Milgadaraon the NSW South West Slopes has seen a significant improvement in soil structure to a tilthy, well aggregated soil with higher humus levels. Rainfall that is received penetrates further into the soil profile and is retained in the soil for longer. Any excess now flows through the profile without taking nutrients with it, reducing the amount lost to run off or evaporation. As a result, water is best conserved and used by plants and animals where it falls.

The key innovation implemented on Milgadara was to restore humus and the natural biological balance back into the soils. To build productive soils the Daly’s developed a humus compost designed to influence all three aspects of soil: chemical, physical, and microbiological. For broadacre farming the humus compost is applied at around 500kg a hectare. The improvement in soil structure and plant health does not come from the quantity of compost applied, but rather, it is a catalyst that supports natural system functioning – including hydrological processes.

Increasing available productive land

And as a final example, on Talaheni in the NSW Southern Tablelands, John and Robyn Ive have invested heavily in revegetation to capture rainfall higher in their property. This increased retention at higher levels has reduced the water table on the lower salt-affected flats and subsequently reduced salinity problems.

Together with additional manual planting, the Ives estimate they have established more than 200,000 trees on their property.

Data from regular monitoring over 20 years shows a significant decline in watertable levels and salinity levels of groundwater. John has estimated that each hectare of ridge top that has been revegetated has led to a beneficial lowering of the watertable in over 50 hectares of nearby adjoining flats, much of which is on neighbouring properties, increasing land available for production.

Left: Bare soils and visible saline seeps previously affected productivity on Talaheni.
Right: The same paddock, with increased vegetation. Through active water management the Ives have restored pastures to productivity

Read more in the Talaheni case study and watch Michael Jeffery interview John Ive on our case study page.

If you take action, it’s amazing what can be achieved to manage your water for efficiency in use and productivity outcomes!

Check in next week to read about a great case study in waterway management.
Until then,

The Soils for Life team.

MANAGING OUR WATER IN A CHANGING CLIMATE

Australians are also some of the highest per capita consumers of water and yet Australia is the driest inhabited continent with variable rainfalls.
Variable rainfalls can have damaging results on the landscape and, as a result, valuable water is lost for use by vegetation or stock

The CSIRO/Bureau of Meteorology 2012 State of the Climate report highlights a trend for “increased spring and summer monsoonal rainfall across Australia’s north; higher than normal rainfall across the centre, and decreased late autumn and winter rainfall across the south.” It also notes that despite higher than average rainfall totals across 2010 and 2011, southwest Western Australia received lower rainfalls and has experienced long-term reductions in rainfall during the winter half of the year.

With rainfall patterns changing, how each drop received is conserved and used is critical.

As discussed in earlier posts the structure of soil is imperative to maximise efficient infiltration and capture of water. This is important not only to sustain vegetation during periods of low rainfall and extreme heat like we’re currently experiencing, but also to better absorb water during high rainfall events. (Remember the “inland sea” floods last year? What difference could properly structured soils founded on optimum organic carbon levels have made?)

Conserving water where it falls

The greatest potential for improvements in conserving water and using it intelligently can be found in increasing infiltration and reducing the current high evaporation rates.

On average, 86% of rainfall initially falls on Australian soils, but around 50% – 25 times the quantity held in all dams – is currently being lost to evaporation.

Consider, that of a typical 100 drops of rainfall that currently fall on the Australian landscape, approximately 12 of these flow into streams and rivers, with only 2 ending up being stored in dams for agricultural, industrial, urban and domestic use. 86 drops fall onto soil, and, on average, 6 of these go into groundwater and 30 into vegetation. The remaining 50 drops are lost to evaporation [2].

By applying regenerative landscape management practices, our case study farmers have shown that rainfall infiltration can be improved. As a result, any rainfall received is better initially captured and then retained for longer, providing sustained supply to plants and livestock. These regenerative practices have also been demonstrated to help reduce erosion and increase available productive land.

Our case studies show that by managing landscapes to improve the soil and maximise rainfall infiltration and retention, production can be maintained – or even increased – despite variable rainfall.

Next week we’ll look at a couple of these stories in detail, and see the techniques they have applied to achieve these results.

The Soils for Life Team

1. Chatres, C. and Varma, S., 2011, Out of Water: from abundance to scarcity and how to solve the world’s water problems, Pearson Education, p8

2. Foran, B. 2007, ‘Who uses all the water?’, presentation at Water, population and Australia’s urban future: 2007 Fenner Conference On The Environment.