Mulch is useful. It provides food for the microbes and other organisms in our soil which then make the nutrients it contains available to our plants. Mulch reduces soil erosion, compaction, water loss from evaporation, and keeps soil cool on extraordinary hot days.

But spreading mulch is not the easiest, cheapest, or best thing to do.

We’re better off growing living mulch. Here’s why.

Living mulch – superior food supply for our soil ecosystem

Living Mulch is a mixture of perennial and self-seeding annual and bi-annual ground cover plants designed to grow mulch right where you need it. Grow living mulch anywhere you usually spread mulch – under fruit trees, shrubs, vine crops, and even in your vegetable plots when you know what you are doing!

Growing living mulch, we increase the amount, diversity and consistency of food supplied to our willing teams of nutrient recyclers and soil structural engineers (see diagram below). [1]

Benefits of living mulch for our soil

Provided with a decent diet, these microbes and other soil organisms work 24/7 recycling plant nutrients and making them available to plants when they are needed.

“Plants get ‘Silver Service’ catering directly from our soil ecosystem, rather than intermittent, and inadequate inputs supplied by us.”[2]

Living Mulch increases soil organic matter and carbon levels

We used to think that above-ground inputs of organic materials like mulch, crop stubble, and compost increased the retention of organic matter and carbon in our soil.

But it’s not true. These above-ground sources of organic materials have a limited effect on carbon and therefore, the organic matter levels in our soil.[3]

Most of the carbon is released back into the atmosphere with each ‘out-breath’ of the soil organisms feeding on the plant remains. ![4] That’s why mulch has the annoying habit of disappearing so quickly!

Only living plants have the technology to provide the roots and root exudates needed to increase organic matter and carbon levels, and hence the structure of our soil,  water and nutrient storage. [5], [6]

By growing living mulch and other living ground covers, we supply additional organic material from roots and root exudates to our soil ecosystem.

Root exudates are the sugars and proteins plants release from their roots to feed fungi and bacteria in our soil.  Plants allocate 20-60% of the solar energy they capture to produce these exudates.

When scientists first discovered root exudates, they thought the plants had something wrong with them and called the phenomenon ‘Leaky Root Syndrome’. But plants know what they are doing! Growing in functioning soil ecosystems plants get 85 to 90% of the nutrients they need via the exchange of sugars for nutrients with microbes, and there are many other benefits.[7]

So next time you’re working hard spreading dead plant material, think instead about growing living mulch to supply energy drinks and carbon sandwiches for your soil microbes!

Living Mulch References

[1] Wendy Seabrook, 2019, Eco-logical Farming Handbook. Publ Learning from Nature

[2] Wendy Seabrook, 2019, Eco-logical Farming Handbook. Publ Learning from Nature

[3] Daniel P. Rasse, C. R. &. M.-F. D., 2005. Is soil carbon mostly root carbon? Mechanisms for a specific stabilisation. Plant and Soil 269, 341–356. (https://link.springer.com/article/10.1007%2Fs11104-004-0907-y)

[4] Michael W. I. Schmidt, Margaret S., et al., 2011, Persistence of soil organic matter as an ecosystem property, Nature 478 (https://www.nature.com/articles/nature10386)

[5] Daniel P. Rasse, Cornelia Rumpel & Marie-France Dignac, 2005, Plant and Soil (2005) 269: pp 341–356 (https://link.springer.com/article/10.1007%2Fs11104-004-0907-y)

[6] Michael W. I. Schmidt, Margaret S., et al., 2011, Nature 478

[7] Wendy Seabrook, 2019, Benefits of Mycorrhizal Fungi (https://www.learningfromnature.com.au/soil-mycorrhizalfungi/)