Historically, the property was extensively cleared of vegetation, which contributed to localised soil salinity and acidity in the region. In the 1980s and 1990s, shelterbelts were introduced back into farming land primarily to control problems with secondary salinity. These days, the integration of shelter and shade into farming systems is often a strong motivation, as well as improving the aesthetics of a farm and providing habitat for native wildlife. There is growing evidence of productivity gains because the reduction in wind speed can lead to higher survival rates for livestock and lambs, which has a flow on to improved weight gains.

Participating in the Riverina project is a natural extension of revegetation work the Scotts have already undertaken with the aim to diversify species and revegetate 10% of the farm. They have planted shelterbelts over the past 20 years, evolving from narrow single rows to wider corridors of native vegetation. Now the Scotts are carefully integrating the shelterbelts between paddocks (see seedlings from recent plantings in Images 7 and 8). 

The Scotts use direct seeding (see Image 9) because it is cheaper and faster than planting tube stock by hand. They accessed direct seeders through LLS and Greening Australia, and with two drivers, the Scotts can plant 90 km of seed in just one day. Steven says that the most important consideration is weed control prior to sowing. The Scotts will hard graze the area and then burn or spray with herbicide.

The results from direct seeding have been mixed, ranging from 80% of the seeds failing to germinate in some instances to areas too thick to walk through in others. Steven says it’s normal to have failures due to a range of unpredictable conditions. Where there are high rates of germination failure, the Scotts come back in with a ute and do more direct seeding. If there are only low rates of failure, then they tend to replant with tube stock. 

Image 9: Direct seeding of shelterbelts at Glen Elgin. Source: The Scotts.

The Scotts hope these new plantings offer a range of benefits that contribute to farm productivity and the conservation of natural assets. In recent years, the Scotts have been celebrating the return of native birds and animals, which they view as central to the farm ecosystem. The sounds and regular sightings of small woodland birds such as superb fairy-wrens (Malurus cyaneus), songlarks (Cincloramphus sp.) and grey-crowned babblers (Pomatostomus temporalis) are a welcome indication for the Scotts of an improving ecosystem. And Steven recently saw his first bare-nosed wombat (Vombatus ursinus) on Glen Elgin:

 ‘A wombat on the farm?! Yeah. Got a hell of a kick out of it.’

Cindy Scott will continue to be closely involved in a study with University of Melbourne to quantify benefits of tree corridors like increased lambing rates or weight gains.

‘We get a great sense of satisfaction when we drive around the farm. We used to be able to see five kilometers and now we can’t see any further than 500 m, and beyond that there’s another tree corridor.’ – Steven Scott

Image 10. Mature shelterbelts at Glen Elgin that show the ongoing planting across the properties for several years. Source: Grow Love

Choosing a monitoring site

Soils for Life worked with the Scotts to identify a location on their farm where they could do their in-field soil assessments, and that was also suitable for any future monitoring of their soils, vegetation and biodiversity. The Scotts chose a site in ‘Munyabla Melon P’ paddock on a lower slope, north of one of Glen Elgin’s many established shelterbelts. 

Setting up monitoring routines

Finding the time to regularly monitor can be challenging, so Steven and Cindy needed to make it manageable amidst their many priorities. To begin with, they are focusing on one location and have chosen a convenient site beside a laneway that Steven drives down daily and where he already has a habit of taking photos of groundcover. ‘We use that area as our basis for the [recent] soil testing, so that everything is basically done within that one little area’, says Steven.

‘I’ve got my groundcover hoop hanging on the fence to remind me. The first Monday of every month I pull up there, I take my photo into the distance and then I’ll walk out 20 paces and drop the groundcover hoop and take photos of the ground.’ – Steven Scott 

In-field assessments

The Scotts did three independent rounds of in-field assessments at the ‘Munyabla Melon P’ site in August 2023, February 2024 and May 2024. Each time, they applied the following monitoring techniques using guides provided by Soils for Life: photopoints, groundcover, soil infiltration, aggregate stability, soil organisms and soil pH assessment. 

The in-field assessments are described below and have been developed into a ‘Soil Health Challenge’, see the Soil Health Assessment Guide at the bottom of the page (with the exception of the pH assessment). Insights from the monitoring are summarised in the next section. 

Photopoints: This assessment involves setting up permanent locations where photos are taken repeatedly to capture changes over time.

Groundcover: A simple way to measure groundcover is by visually estimating the percent of the soil surface within a confined area that is covered and not bare. 

Steven has a well-rehearsed routine for assessing groundcover once a month, allowing the Scotts to see changes over time and under different conditions (see Images 12 and 13).

Soil infiltration: Soil infiltration is the downward entry of water into the soil. The rate at which water can infiltrate can be estimated in the field by recording the time it takes for a volume of water to enter and move through the soil. 

Steven had not done water infiltration assessments prior to the project and now plans to add this assessment to his monitoring routine, along with periodic aggregate stability assessments (see below) to inform grazing and cropping decisions. 

Aggregate stability: Soil structure regulates the movement and storage of air, water and organisms, and therefore nutrients, in the soil. Soils with stable aggregates are more likely to retain their structure and are better able to withstand the forces imposed by wetting and drying, raindrop impact, stock trampling, cultivation and other disturbance.

Soil organisms: Soil organisms are responsible for many soil processes, including contributing to the development of soil structure, the breakdown of organic matter and the cycling of nutrients. One of the simplest methods for assessing the soil organisms that are visible with the naked eye (e.g. worms, beetles, spiders, ants, etc.), is to record the number that can be seen in a sample of soil within a defined period of time.

Soil pH assessment: Soil pH is the acidity or alkalinity of the soil. Soils may be naturally acidic or alkaline, depending on the parent material on which they formed. Agricultural practices also influence soil pH, often removing alkalinity from the farming system, which results in an increase in soil acidity over time. A number of methods for estimating soil pH in the field are available. The Scotts used the soil pH kit provided as part of the project, which is readily available from hardware stores.³

³The kit is called a Manutec Soil pH Test Kit and comes with easy to follow instructions. The kit is based on Raupach and Tucker’s field method for assessing soil pH. See Raupach, M and Tucker, B (1959) The field determination of soil reaction. Journal of the Australian Institute of Agriculture Science 25:129−133. To see a soil pH demonstration, visit: https://www.youtube.com/watch?v=HZz3-cv_GGc&t=123s

Sampling for lab tests

To supplement in-field monitoring, the Scotts collected soil samples from one location at the ‘Munyabla Melon P’ site for laboratory analysis. The samples were collected from four different depths in the soil (see Image 17) and submitted to the laboratory for a range of soil physical, chemical and biological tests. The purpose of sampling at a single location was to provide the Scotts with a more in-depth account of the soil at their monitoring site so they can track changes in these soil properties over time. With additional investment, soil monitoring and sampling at multiple locations across Glen Elgin would provide the Scotts with a broader understanding of their soils.

The soil at the ‘Munyabla Melon P’ site is well-drained, with a gradual increase in soil texture from loam to clay loam and a neutral pH trend. Based on the in-field assessments, observations at the time of sampling and the results of the soil testing, the most notable potentially limiting properties are the weak soil structure, low organic matter and low cation exchange capacity (CEC) below 5 cm depth in the soil and the low quantity and activity of soil organisms.

Organic matter and fertility

Soil organic matter is complex, comprising many components, including (but not limited to) soil organisms, plant residues, active soil organic matter and stable organic matter (humus). Because of its complexity, soil organic matter is estimated from soil carbon measurements, and the Scotts previous soil testing has included soil carbon. 

The lab results from the ‘Munyabla Melon P’ site show that total carbon is moderate to high (3.3%) in the 0– 3 cm sample, which equates to an estimated soil organic matter of 5.8%. While this result is 1–2% higher than the Scotts have seen in previous soil testing at different locations on Glen Elgin, soil organic matter (and therefore soil carbon) can be highly variable over time and within, and between, soil types. 

Soil organic matter can range from recent (e.g. fresh plant residues and animal manures) to ancient (e.g. charcoal) and its cycling is largely dependent on water availability, soil structure and soil pH. The building and cycling of soil organic matter, or ‘turnover’, is largely dependent on climate and soil type. Achieving sustained increases in soil organic matter is typically a long term process that occurs over decades. Steven recognises this and sees the building of soil organic matter and carbon as a ‘slow game’ but something he and Cindy will enthusiastically continue to work on.

Soil cation exchange capacity is a measure of the soil’s capacity to exchange and retain basic cations (and therefore nutrient availability for plants). It is also an indicator of soil fertility and is influenced by the soil clay content, organic matter levels and soil pH. 

The CEC of the monitoring site soil at Glen Elgin was low to moderate from 0–3 cm and low from 5–50 cm in the soil. The higher CEC in the 0–3 cm sample reflects the high soil organic matter, and the decrease in CEC from 5 cm depth in the soil reflects the decrease in soil organic matter and the amount and type of clay in the clay loam subsoils. 

In an effort to increase soil fertility in certain paddocks, the Scotts have added phosphorus and lime, experimenting with different rates of application (from 2.5 t/ha to 4–6 t/ha) incorporating to about 10 cm depth in the soil. Results from previous soil testing indicate that the soil fertility has increased in areas where phosphorus and lime have been applied.

A question that remains for the Scotts is whether soil acidity exists to the extent that incorporating lime deeper than 10 cm and maintaining a higher rate of application are viable management options. This is a common query raised by farmers who struggle to find efficient and affordable solutions to subsoil acidity.

Because soil organic matter, particularly humus, has a CEC many times greater than any clay type, increasing its levels in the topsoils will not only stabilise the topsoils, but will also increase soil water retention and act as a substantial source of nutrients for the soil organisms and the plants. 

The Scotts participation in the project has also led to an increased understanding of nutrient balances in the soil, in particular the relationships between CEC, clay content, organic matter and soil pH. 

Soil organisms 

Soil organisms contribute to soil health in a number of ways. Many are important in helping break down organic matter, cycling nutrients and the mineralisation of nutrients into plant-available forms. Others contribute to soil aggregation via their secretions, which bind soil particles together to form aggregates. In addition to being critical to soil fertility, the absence of abundant, diverse and active soil biology may contribute to soil instability and soil structural decline. 

Soil organism counts conducted at the Elgin monitoring were low. Considering their focus on plant diversity, commitment to reinstating trees across the landscape and the steady increase in land area that is under pastures rather than cropping, the Scotts expected to see more ‘life in the soil’ at Glen Elgin. While soil organism counts are a reasonable indicator of the presence of soil organisms that we can see, there can be any number of explanations for low counts, including: monitoring when the soil is too wet or dry (which was common for many of the project participants, including the Scotts); low soil organic matter levels representing a lack of food sources; and compacted, structureless soils resulting in a loss of habitat and limiting the movement of soil organisms. 

Many Australian agricultural soils are bacteria-dominant due to the loss of fungal communities following the clearing of trees and shrubs, soil disturbance (tillage destroys fungal hyphae and mycelium) and the use of fungicides. The low count and activity of the soil fungi in the 0–3 cm sample from the ‘Munyabla Melon P’ site suggests that the mycorrhizal (fungus to roots) relationships responsible for microbe-root-plant interactions, such as water and nutrient uptake and exchange are low, limiting nutrient cycling and availability. 

In such a scenario, the soil’s capacity to store and transmit oxygen, water and nutrients can be improved by increasing soil organic matter, beneficial fungi and the diversity and abundance of food sources for organisms living in the soil. One way that the Scotts are working on increasing soil organic matter and nutrient cycling is by introducing different species of dung beetles. The Scotts have learned that certain species of dung beetles are active at different times of the year, and they are aiming for an ‘annual blanket’ of activity to help stimulate microbiology and circulate nutrients.

Soil infiltration, sodicity and stability 

Over time, the natural weathering of soil parent materials can result in nutrients, clays and salts accumulating in the soil. If one of these salts is sodium, and the sodium is associated with the clays as an exchangeable cation, the soils are described as sodic and potentially unstable.

The soil test results showed that the soil at the ‘Munyabla Melon P’ site is non-sodic from 0 to 40 cm, with exchangeable sodium percentages (ESP) ranging from about 3 to 4%, and sodic at 40 cm, with an ESP of 8.7%. While the common threshold for sodicity is 6%, soils with ESPs as low as 3% can be unstable. 

Steven has observed that the ‘stability of most of the soils is fairly sound’. Given the soil test results for aggregate stability show the soil to be moderately stable from 0–40 cm, and the in-field aggregate stability assessments yielded a similar outcome, his observations seem well-supported. These outcomes, however, are based on a small number of in-field observations and lab tests and may not be representative of the property as a whole.

One of the many benefits of observing, sampling and testing deeper in the soil is being able to identify potential limitations to soil workability and productivity such as sodicity across the farm. Subsoil properties not only influence soil water movement and storage, and the depth at which plant roots can grow to access water and nutrients (effective rooting depth), but they might also reveal other limitations to productivity. 

At Glen Elgin, if it is present deeper in the profile, soil sodicity may only be an issue if the soils are exposed or disturbed and subsequently wetted (e.g. during the process of building a dam, or brought to the surface through cultivation, when dispersion can occur).

Soils with low stability, including sodic soils, are more susceptible to soil structure decline than stable soils. This loss of soil structure limits key soil processes such as soil water infiltration and aeration, resulting in a less than ideal habitat for soil organisms and plant roots. In heavy clay soils this would prove a limitation to soil water infiltration, but in the ‘Munyabla Melon P’ soil, the lighter loam to clay loam textures will assist the movement of water into the soil. 

Steven observed soil water infiltration rates ranging from slow (15 mm/hr in August 2023) to rapid (260 mm/hour in February 2024), noting that the infiltration rate slowed after 60 minutes for the February monitoring event. This is not unexpected, as infiltration rates tend to vary depending on a range of conditions at the time of monitoring, including the moisture content of the soil. 

Future monitoring 

Prior to their involvement in the Riverina project, the Scotts had not undertaken any in-field assessments of their soils. The farmer-led soil assessments that were introduced as part of the project encouraged the Scotts to observe their soils more regularly and to consider how their paddock observations might relate to soil function. 

Steven now sees value in continuous observation and the periodic paddock assessment of soil properties to inform their grazing and cropping decisions. He believes that the in-field assessments of soil water infiltration have contributed to their overall understanding of how much water might be available for plant growth, and this has informed them when it comes to livestock rotations to avoid overgrazing certain paddocks.

Participating in the Riverina project has led Steven to reflect on ‘how little value he had been getting out of lab results in the past’, and ‘how little he really understood about what the soil test results mean’. Although he is a firm believer that monitoring is essential to good management, in his experience not all of the data he has collected over the years has been useful. He found it ‘incredibly valuable to have expert consultation’ in interpreting the soil test results and relating the results to practical implications in the context of his farming enterprises.

The Scotts are interested in discovering how variable their soils are and intend to progress their monitoring routine. They recognise the value of more regular sampling and testing, including of the subsoils, but they would also like to maintain the higher level of interpretation that the Riverina project offered so they can use the information more effectively. 

Reflecting on their participation in the Riverina project activities, and the results of the farmer-led assessments and soil monitoring site test results and interpretation, Steven recognises that certain soil and landscape characteristics are beyond his control. However, he also acknowledges that while they have adopted many worthwhile practices at Glen Elgin, there is more they can do to improve their overall soil functionality, especially through managing their grazing regimes.