Soil Scientist Q&A

Published on
July 20, 2023
We sat down with principal soil scientist Declan McDonald from Regen Soils to answer some of the most commonly asked questions about the enrich360 organic fertiliser and its applications:

Q: Does what I eat affect the fertiliser from my dehydrator? How can the food waste input impact the composition of my fertiliser?

A: Different foods have different nutritional properties. If your diet contains high protein for example, you will be eating a relatively high proportion of nitrogen and sulphur, and these will show up in waste food. If your diet consists of a lot of processed foods, it is likely that elevated salt will show up in waste food. And, if your diet consists mainly of vegetables, leftover food will probably be of lower nutritional value given that these foods have higher water content and are less nutritionally dense than say, steak.

Food that is high in protein will contain high levels of protein-building elements such as nitrogen and sulphur. Fruit and vegetables contain a wide and balanced array of essential elements such as calcium, magnesium, potassium and a host of trace elements. Carbohydrates (bread, pasta, lollies) contain a relatively narrow array of carbon, hydrogen and oxygen. As a general rule, all food that is recommended for human consumption will reflect its value in the fertiliser produced by a food dehydrator. 

Q: Isn't enrich360 fertiliser just dry food? If so, does that make it fit for human or animal consumption?

A: Enrich360 fertiliser is produced by dehydrating food waste at high temperatures. Given that food contains relatively high moisture contents, driving off most moisture with sustained heat concentrates the nutrients. The resulting product is a compost-like material that can be used as a fertiliser.  Analysis has shown a chemical profile not dissimilar to blood and bone. Therefore, Enrich360 fertiliser should be used in a similar manner to blood and bone.

Q: If my dehydrator is producing more fertiliser than I can use, are there any other uses for the bioproduct?

A: Dehydration of left-over food concentrates nutrients to a high degree.  This means that the Enrich360 fertiliser has a high level of embedded energy. The material could therefore be used in anaerobic digestion, composting or (theoretically) in a waste-to-energy process such as incineration. However, the best and most cost-effective use is simple ground application as a fertiliser, so if you are producing too much, contact your local landscape gardener, community garden or council to see if they can benefit from your surplus.

Q: What is the role of fertilisers in soil health and plant growth?

A: When we grow food and vegetables in home gardens or commercial farms, the export of food and fibre (whether it is apples, sugarcane, beef or wool) removes nutrients from the soil. For many thousands of years, humans have understood the benefit of adding organic matter – usually in the form of fresh or composted manures – back to the soil. We understand now that these manures contain valuable plant nutrients to grow the next crop. Enrich360 fertiliser effectively closes the loop and quickly returns nutrients in left-over food back to the soil.

Q: What are the pros and cons of using enrich360 organic fertiliser vs. a synthetic one?

A: Synthetic fertilisers are usually highly concentrated. This means that a small amount is required to address soil nutrient deficiencies. However, synthetic fertilisers do not feed the huge numbers of soil organisms. Research has shown that continuous use of synthetic fertilisers is detrimental to soil life. Soils and the soil community have evolved to receive and process fertilisers in organic form. Enrich360 – like most organic fertilisers – contains all essential macro and micro elements together with a significant level of organic carbon, the backbone of soil health.

Q: How can farmers and gardeners determine the optimal type and amount of enrich360 fertiliser to use in their soil?

A: Soil testing is the only reliable way to optimise soil condition and nutrient input. However, the organic nature of Enrich360 fertiliser means that very high application rates would be required to over-apply any nutrient. The general rule for soil fertilising is ‘a little and often’. This means that a light application of Enrich360 fertiliser in the order of 50g/m2/season is a good guide to maintenance of soil health and nutrient sufficiency.

Q: How do soil characteristics like pH, nutrient content and organic matter content affect the success of a fertiliser?

A: pH influences the availability of most nutrients. At very low pH values (≤5.5 in water), aluminium can become toxic to plant roots; at very high pH values (≥8.5 in water) nutrients such as phosphorus, iron or manganese can become immobilised and unavailable to plants. So long as pH is corrected to sit between about 5.8-7.0, nutrient availability will not be constrained.

Existing soil nutrient levels can only be determined by soil testing. If that testing shows that macro and micro elements are already at optimal levels, it is unlikely that any plant response will be seen. In contrast, if soil nutrient levels are very low, plants will respond very strongly to application of fertiliser.

Organic matter content does not negatively affect fertiliser application, especially if the fertiliser is organic. Synthetic fertilisers, particularly high nitrogen fertilisers, will deplete soil organic matter over time. Organic fertilisers, being less concentrated and containing carbon, will support and are more likely to increase organic matter over time.

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