MORE THAN JUST N, P, K

case study farms have demonstrated how to build healthy soils and the production outcomes that can subsequently be achieved.

By building good levels of soil organic carbon and supporting soil biology, nutrients are much more easily and effectively transferred through plants and into the food and fibre on which we depend.

Giving back through compost and green manure crops

Although these natural cycles are inherently regenerative, by harvesting our food and fibre and moving our stock we are breaking the cycle. We must consciously give back to the soil to ensure nutrients and minerals do not become depleted.

Bill and Rhonda Daly of Milgadara on the NSW South West Slopes, and Cam and Roxane McKellar of Inveraray Downs in the NSW North West Plains are responding to any loss of nutrients from harvested products, by the regular application of organic compost. This allows for recycling of off-farm nutrients by re-introducing composted materials back on to the property.

The Dalys have restored their soil structure, chemistry and biology through applying specially formulated humus compost. As a result, they have increased soil organic carbon (SOC) levels, improved cation exchange capacity (CEC), their pastures are more diverse and prolific and their crops are producing greater yields. The Dalys have also experienced an improvement in the quality of the wool their sheep are producing and lambing percentages have increased. This could potentially be linked to the improved nutrition in their pastures.

The Dalys are delighted by the outcomes they have achieved through the application of humus compost and are so enamoured with the product they have developed that they seek to share it with others through their business YLAD Living Soils.

Improved plant nutrition is also linked to higher test weights in crop production. As a result of improved soil structure, nutrient cycling and water holding capacity, it is possible to achieve the same yield with lower applied nitrogen. Improved translocation and allocation of other nutrients to the grain, as well as improved water and carbohydrate transfer occur when plants are less moisture stressed – conditions generated by healthy soils.

On Inveraray Downs on the Liverpool Plains, the McKellars are regenerating what used to be some of Australia’s best soils, which had become degraded through cultivation and use of inorganic fertilisers and biocides. The McKellars have re-designed ecological cropping practices by altering crop rotation, applying compost and introducing stock into production – all of which are contributing to restoring essential biological processes, nutrient cycling and healthy soils. As a result, they now produce better quality and more healthy and nutritious food – more sustainably and with lower input costs.

Cam and Roxane are capturing increased nutrients such as nitrogen from plant growth through incorporating green manure legume crops, and through the retention of crop stubble. Consequently, greater soil microbial population response is promoted, which in turn feeds improved cycling of the other nutrients needed for plant growth. Under the previous conventional management system, this would have been lost to burning and oxidation.

By moving from synthetic to compost-based minerals for nutrient replacement, the McKellars are now also adding trace elements, organic matter and biological by-products of the compost process that contribute to soil fertility over and above simple nutrient replacement.

Hopefully the examples over the last few weeks have demonstrated the range of activities that can be taken to improve soil health. You don’t have to do them all or all at once, but the important message for all our farmers and land managers is just to start. Any step towards improving your soil health is a step in the right direction.

Leave a comment or contact us if you need any more support in getting you started.

Wishing you healthy soils over the holiday season, in 2013 and beyond. Tune in early next year as we start to explore the importance of water management and what we can do to use it more effectively.

The Soils for Life Team

THE WONDERFUL WORLD OF SOIL BIOLOGY

case studies have demonstrated that by supporting the biological activity in their soil, they can increase the nutrient availability, health and productivity of their soils. This process is becoming more widely understood, as new technologies provide access to much more detailed information about the biology of the soil and how to adjust it to improve productivity and profit (see the recent ABC Landline episode on Soil Secrets).

Our case study participants used techniques such as the application of organic composts, worm juice and biological amendments to enhance the biological activity and productivity of their soils. (It is important that appropriate amendments are tailored to individual soils.) They also used stock management practices to control grazing pressures and distribute nutrients, the direct-drilling of seed and reduction or cessation of chemical inputs.

From sand to soil…

By focusing on restoring the natural biology of their soils, farmers in WA and SA have been able to regenerate nutrient-poor sands back into productive and resilient soils.

In the WA Central Wheatbelt, Ian and Dianne Haggerty of the Prospect Pastoral Company coat seeds with beneficial micro-organisms before sowing and apply biological fertilisers, including high grade worm liquid and compost extract, at the cost of $30 a hectare. By limiting soil disturbance through direct-drilling or no-till cropping, they also limit disturbance to micro-organisms and fungi. As a result, they are producing consistent crops and premium fat lambs on very limited rainfall (as little as 100mm in the growing season!).

Soil under the Haggerty’s crop is clearly improved with organic matter after just two crops, compared with the spadeful of sand taken from the edge of the property.

Similarly, David Clayfield of Clover Estate in SA adopted a soil biology building program. This incorporated an annual application of compost extracts (at 50 litres a hectare), as well as bio-fertilisers to help address plant nutrient imbalances, cycling and availability limitations in his sandy soils. As a result he can now grow pastures to help rear calves for export as dairy heifers with a 33% production increase, using 25% less irrigation. And look at the changes he’s achieved in his soil!

After 15 years of organic treatments, David Clayfield’s sandy soils are darker with higher organic matter content and biological activity, enhancing nutrient transfer and water-holding capacity.

David’s soil improvement photos almost rival Colin Seis’ from last week’s post. Don’t forget to take a picture of your soil profile and share it with the Soils for Life Community.

The Soils for Life Team

IMPROVING THE CARBON CONTENT OF SOIL

last week’s post for why that’s important.

Soil organic carbon (SOC) is the main constituent of soil organic matter (SOM). SOM is formed by the biological, chemical and physical decay of organic materials on the soil surface and below the ground. On average, SOM is composed of 50% carbon, 40% oxygen, 3% nitrogen and smaller amounts of other elements as micronutrients.

SOM varies in its stability. Some is labile, relatively quickly biodegradable, and other components are more stable (non-labile). The ratio of labile to non-labile depends on microbial conditions.

As in nature, we can transform arid soils into healthy soils and biosystems by accelerating pedogenesis processes..

The carbon sequestration potential under conventional farming practices should not be seen as the maximum possible or be the drivers of policy, when there is evidence that numerous innovators have been achieving greater bio-sequestration outcomes by some order of magnitude.

It is possible to biosequester up to 10 tonnes of stable carbon per hectare per annum back into our soils. This would regenerate their structure, hydrology, nutrient dynamics, bio-productivity and resilience.

How to increase soil carbon levels

The easiest way to increase your soil carbon levels is to incorporate more organic matter into and onto your soils, such as by maximising ground cover and mulching.

Generating SOM was a primary step for many of our case study farmers to improve their soil health, and this took a range of different forms…

Colin Seis of Winona near Gulgong in the NSW Central Highlands has developed and implemented a completely new cropping technique – ‘pasture cropping’ – which has led to dramatic increases in soil and soil minerals, including SOC. Pasture cropping involves direct-drilling crops into dormant native perennial grasses. Colin has also integrated time-controlled planned grazing, with sheep grazing prior to sowing, during growth before seed-set, and after harvesting. This technique promotes ongoing groundcover and minimal soil disturbance, supporting high biological functioning and constant formation of fertile soil.

Extensive soil testing on Winona, including paired-site analyses by the University of Sydney through the Communities in Landscape project, has shown that this technique has increased SOC by 203% in ten years. SOC has been measured up to depths of 500mm. In total, this equates to around 45 tonnes of SOC a hectare, or per hectare storage of around 170 tonnes of CO2 (equivalent) over the ten years.

Importantly, 78% of the newly sequestered carbon on Winona is in the non-labile (humic) fraction of the soil. This is therefore much more stable and significantly less subject to degradation.

In a very different environment in the NSW North West, Graham and Cathy Finlayson of Bokhara Plains are restoring the soil structure to claypans in the rangelands. Through planned grazing practices, stock are being used to break up the surface of the claypan, which formerly comprised 50% of their land. (See the transition in the image above.)

High density stock levels trigger soil disturbance, exposing seed already present or carried in from manure, stock hooves and/or hide and enabling it to germinate. The stock density used by the Finlaysons also ensures nutrient deposit (from urine and manure) carried in from other areas of higher natural fertility.

By allowing water and seeds to penetrate and also leaving manure fertiliser deposits, the claypan and degraded areas of Bokhara Plains are becoming revegetated. Soil structure is continuing to improve and SOC levels are increasing from the greater plant biomass and root systems in soil.

By regenerating the soil and increasing groundcover, the Finlaysons have significantly increased productive land on their property and improved their sustainable carrying capacity. Through addressing the health of the soil, the Finlaysons are creating a viable business and are moving towards drought-proofing their property.

It’s amazing how fertile soils can be built, and the photos of the soil and pasture changes from Colin Seis and the Finlayson’s places are inspirational. What does your soil look like under the surface? What percentage of groundcover do you have on top?
What are you do to improve your soil carbon levels?

Click on ‘Comments’ below and let us know.

Get involved! Take a photo of your soil profile, including a ruler or measure – maybe from various parts of your property (or your back yard or veggie patch) – and post it on our Facebook page or send it to info@soilsforlife.org.au and we’ll share it for you. Let’s see how deep our topsoils go! (This will also serve a good record for your own regeneration journey!)

Until next week, when we look at the wonderful world of soil biology,
The Soils for Life Team