Healthy Soil = Healthy Food
A short report on a Seminar presented by the Local Land Services, Greater Sydney, NSW Govt. on March 4 2014.
The aim of this Seminar was to present practical tips for producing healthy food in an urban environment.
The location of the Seminar was at the Coal Loader Centre for Sustainability, 2 Balls Head Drive Waverton. This location is a sustainability educational centre and includes a Community Garden on the grounds; the development of this garden was part of the third presentation. This interesting and historical centre is open 6 days a week Mon-Sat, well worth a visit).
Attendees included representatives from Community Gardens, Schools, Street Verge growers and some commercial and council interests.
There were three presentation topics:
A good Soil Recipe – Michael Hewins, Milkwood Permaculture.
Tips included how to cultivate a healthy soil structure and a suggested produce cycle to maintain effective production.
Creating safe produce – Prof Mark Taylor & Macquarie University’s VegeSafe program team.
A discussion on Soil contaminants, their usual sources and identification using technology. Soil sampling was carried out on soil samples brought by the participants using their handheld XRF “gun”.
Case Study of a successful Community Garden – Ralph Forinash, North Sydney Council.
This presentation showed how North Sydney Council, under the management of a dedicated council employee, has developed three Community Gardens in its area; on a bitumen surface, over contaminated soil and on a difficult and small sloping site.
This was followed by a brief facilitated discussion by the attendees covering further subjects of interest worthy of subsequent follow-up by others, including Macquarie Uni.
The introduction to the seminar mentioned that the interest in local growing was becoming worldwide in cities and that the urban environment presented unique challenges. This seminar about healthy local produce has a ‘back to basics’ approach. Soil health is a huge field of study and this seminar can only be a brief introduction.
1. A good Soil Recipe
Good gardening is an exercise in observation skills, seeing patterns, and soil manipulation, both organic and permaculture.
Healthy soil is alive (with microorganisms) so feed the soil not the plants.
Soil cultivation is both biological (bacteria and fungi) and physical (types of dirt).
Soil in nature is generally covered (leaf litter, etc.).
Nutrient dense food comes only from nutrient dense soil. Feeding the soil with compost requires balance and diversity. Compost is a stimulant and is concentrated; it should be aimed at cultivating the soil’s biology.
Digging the soil stimulates bacteria growth and produces a short term stimulus.
Worms and hot composting builds up bacteria and fungi. Overuse of leachates, concentrated nutrients such as seaweed teas, worm wee, etc., does weaken the plant’s ability to use the soil.
Mulches provide a covering protecting the biological activity and moisture retention (lucerne, etc.); green manures allow the soil to rest awhile.
The suggestion is to move away from just physical cultivation.
This suggested produce cycle over time will feed and develop the soil for each successive crop:
Green manure (cover crops i.e. vetch, oats, etc.) coming into winter
Vegetable fruit crops (any that produce crops to pick)
2. Creating safe produce
“VegeSafe” is a Macquarie University pollution research program, its aim is to identify soil pollutants and their distribution, initially in the Sydney area.
They have designed a handheld tool to identify soil contamination, mainly from heavy metals in the soil, on-site alleviating the need to have soil sent for laboratory processing at some cost.
The most common contaminant found is lead, the sources of which include petrol, paint, industrial pollution and introduction from various external soil sources (can include dumping or ‘clean’ waste or even ‘new’ soil)
These contaminants end up in the plants and subsequently in the food, or they can be ingested from the soil and even inhaled from soil and dust.
VegeSafe provides free soil testing to Sydney residents, advice and affordable solutions.
VegeSafe is on www.facebook.com/pages/vegesafe/571316076267515
3. Case Study of a successful Community Garden
The Coal Loader location includes a Community Garden on the grounds; the development of this garden commenced with a bitumen surface. Slides showed the development of several garden types including Boxes, Keyhole gardens (with brick walling), an in-ground level garden and a ‘no dig’ garden plot
Another site, Milson Park, was over contaminated soil and necessitated a protective layer (“geotech”) between the garden and the subsoil (preventing plant roots from entering the contaminated soil), a layer of crushed compacted sandstone and another layer of gravel, etc. was then placed over this protective layer which became the walkway surface between the garden plots. Again use was made of Boxes and keyhole garden plots.
The third site was on a difficult and small sloping site. Tests showed no contamination and so the garden was introduced straight into the soil, this site is still under development.
We finished the Seminar with a most delightful lunch, catering for all tastes (vegetarian, gluten free, dairy free, etc., etc.). We have learnt a tremendous amount and we have included everything that we can remember (with help from our notes) in the report above and hopefully our community garden members can benefit from this information.