Rooting for Compost and Composting for Roots

On the 14th of August, a large group of farmers came together in Dalwallinu to learn more about compost, what it is and how and why it works to improve soil health.

Ken Bailey was on hand to explain some of the science behind compost and how it works in the soil. Ken brings with him over 25 years of experience working in this field, and describes himself as a biological and compost nutritionist. He certainly knew his stuff.

We were also lucky to be joined by Ellen Walker of Earthwhile Australia.  Ellen brought along her microscope to give people a chance to take a look at the microscopic biology in soils and help us understand that our soil is literally a living breathing entity.

Compost is used to improve soil quality and soil health. Compost helps soil to build aggregates, where compost and other organic materials – including humus – bind with the silt, sand and clay particles. This what gives a healthy soil a crumbly texture. This loose texture improves soil aeration, increases water holding capacity, improves drainage and provides an easier substrate for plant roots to grow in. More roots in the soil in turn help to control and reduce erosion. A five percent increase in organic material in the soil will quadruple the water holding capacity of the soil.

Well-made compost also provides a rich supply of nutrients, essential for soil microorganisms. It can add nitrogen, phosphorus and potassium as well as many micro-nutrients including mangenese, copper, iron, zinc and molybdenum. The exact nutrients available will be determined by the materials used for making the compost.  For example, animal manures tend to be rich in molybdenum. These nutrients feed the soil microbes which in turn feed the plants through a mechanism known as the Rhizophagy cycle. This is a process whereby bacteria and fungi cycle between a free-living phase in the soil and a plant-dependent phase within cells of plant roots.  Simply put, microbial endophytes (bacteria and fungi) harvest nutrients from the soil, and these same nutrients are extracted from the microbes in the cells of plant roots. The plant will exude sugars through its root hairs into the surrounding soil, which feeds the endophytes and helps to attract them to the plant, in effect the plants are “farming” the microbes.  You can read more here: https://phys.org/news/2018-09-harness-microbes-nutrients.html.

Ken explained that different plants will create an environment around their roots that promotes different soil biology. The more diversity of plants you have growing in the soil, the greater diversity of soil biology you will have. A system that promotes a monoculture is always more susceptible to disease, and so the diversity in soil biology from practicing crop rotations (or pasture-cropping or multi-species cropping) helps to build disease resistance. Compost helps to enhance the soil biology too, creating a healthier soil, in turn creating healthier plants that are more resistant to disease and insect attack.

Compost extracts were also discussed. The idea of this practice is to extract the microbes from the compost, using water and aeration, to create a liquid product, which can be sprayed onto foliage or seed, and helps to drive microbial activity. Ken suggested that there is a benefit to broadacre systems for spreading both the bulk compost product, and using a liquid compost extract.

Once our brains were spinning with all this new information, we headed out to the Jorobi Natural Fertilisers site to see where the magic takes place. Rob Harris, who owns and manages the business with his wife Jo, talked us through the process from start to finish.

Rob discussed what raw materials they use, where they source them from and the timeframe of creating a mature compost. Rob then carried out a demo of the compost machine which moves down the rows, mixing, turning, aerating and adding water to the piles. It is a fascinating process to see on a large scale. By changing the inputs, the Harris’s are able to create different composts which are suited best to different situations.

This was followed by a look at a local demonstration site. Here, compost was added several years ago, and the soil is still showing a marked difference from the untreated area.  Some enthusiastic participants started literally digging deeper to see what might be going on under our feet. It was a great reminder that the humble spade is one of the greatest tools we have to understand a little about what is or isn’t happening in our soils and on our farms.

Unfortunately, we ran out of time to make it out to the second trial site, which was a previous salt scold, where compost has been added to great effect. Ken did show us some photographs earlier in the day of the same site over several years, and it looks very promising.  There was plenty of interest in the application of compost to salt though and we aim to follow this up in the future. Please contact the RALF team if you would be interested in being notified about future compost events or if you are interested in trialling something on your property. 

Do be aware that as with all things, there can be huge variation in the quality of compost product, so make sure you research any products you intend to use on your property.

Special thanks to Ken Bailey of Haslen Technology, Rob & Jo Harris of Jorobi Fertilisers and Ellen Walker of @earthwhileaustralia for sharing their time and knowledge.

If you would like to know more, please contact your local RALF’s.

Lizzie King (E) [email protected] (P) 0447 361335

Annabelle Garratt (E) [email protected] (P) 0448 986879

Lizzie King & Annabelle Garratt – Regional Agriculture Landcare Facilitators

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