It’s a curly question, for sure, and one I wouldn’t have taken a stab at answering (without a wry smile and a clever pun) before attending a workshop at the Greater Sydney Local Land Services (LLS) Demo Farm in Richmond earlier this month.
Focused on recognising the value of healthy soils, the hands-on event covered:
* simple techniques to assess the current condition of your soil
* practical tips to address limiting factors on your property
* what is natural capital, why is it important and which new natural capital support services are available for you.
Hosted by Greater Sydney LLS’s Sustainable Agriculture Facilitator, Richard Stephens, the workshop also featured the relatively new concept of ‘Natural Capital’.
“In a nutshell, it’s the value of all living and non-living parts of the landscape that we rely on to survive – water, trees, soil, air, animals, ecological elements,” explained LLS Natural Capital Advisor, Madeleine Florin. “In the past, we’ve used the term ‘nature’ to describe it.
“These natural ‘assets’ provide free ecosystem services [air and water filtration, food and fibre production, pollination] and support our environment, society and economy, so it’s vital to protect, manage and restore them.”
When asked why the rebrand, Madeleine said: “One way of viewing natural capital is to consider it like other forms of capital such as financial, built, human and social capital.
“Investing in it creates value for your business, your property management and the broader economy. It can help you improve farm productivity, expand or safeguard your market access, or save on input and finance costs.
“It may also allow you to take part in environmental markets and earn a return. For example, the carbon market enables land managers to create and sell carbon credits from storing carbon in soils and vegetation.”
While environmental markets are in the early stages in Australia, this is likely to change sooner rather than later in line with worldwide movement in this area.
Testing times
Agronomist Ben Azzopardi then ran us through healthy soil do’s and don’ts, including chemical, biological and physical factors, before heading into the field to conduct soil testing.
“What you need to ask yourself is ‘What’s your goal? Why are you doing this?’ When you know the answers to these questions then you can work out a regime.
“For example, if it’s to grow lettuce, then you’ll want to work out a program that enhances the soil to produce the juiciest lettuce you can. If it’s to mitigate weeds, your program will be different. But starting with healthy soil, for pretty much any enterprise, is the answer.”
Soil composition is key to this. For instance, heavy clay soils will require different additions to sandier or humus-rich versions.
“pH is vital too,” said Ben while digging up a handful of dirt and, using a basic kit bought from any hardware or garden store, testing it. “It’s pretty much spot on here, in the neutral zone, which is around seven. Lower than that and the acidity increases, higher and you could have an alkalinity issue.”
After discussing what amendments to add to balance each, Madeleine introduced us to her penetrometer, which is designed to provide a measurable indication of the hardness or compaction in soils.
“This type of test gives you an impression of how much work the plant roots need to do to get through the soil,” Madeleine said. “So, if you’ve got a really poor soil structure, then your plants roots will have to work harder and might not be able to make it through at all.”
“You want a soil where there’s lots of room for water and air to get in, but not so much that it doesn’t stay in when you need it.”
The other test was all about water infiltration.
“We use a piece of drainage pipe, cut to 12.5cm, and embed it in the soil to a depth of 2.5cm.
“Then we fill the pipe up to the top, which gives you 100mm, set a timer for six minutes, and measure how much water has gone into the soil. Multiply that by 10 and you get a rate per hour. This gives you an indication how well your soil absorbs water. A higher infiltration rate is generally better.”
Soiled undies?
At the end of this demo we headed back inside to find eight pairs of cotton undies laid out on a table. Each was in a state of disintegration.
“We buried these for about six weeks in plots that had received different amendments, including poultry manure, kelp-based liquid and frass, to see how quickly they broke down,” Richard explained. “Generally speaking, the faster they do, the greater the biological activity and the healthier your soil because these same soil organisms can break down plant materials in much the same way.
“You can do this test at home. In fact, you might want to soil your undies a few times, and at different spots, to get the best results.”
Touche, Richard. Touche!
Find about more about Greater Sydney Local Land Services events.
Story and photos/video: Liz Ginis, Director Communications & Marketing, RDA Sydney
