From oas@alphalink.com.au Tue Nov 16 13:37:10 1999 Date: Tue, 16 Nov 1999 21:00:29 +0930 From: Chris Alenson To: sanet-mg@ces.ncsu.edu Subject: Food nutrition and soil regeneration I have followed this interesting subject for some time and I am grateful to Steve Diver and the many respondents for further references on the subject. Our organisation has just completed a study looking at mineral levels of four vegetables (silver beet, capsicums, beans and tomatoes) to see whether soil manipulation could improve the nutritional characteristics of these vegetables. Equivalent vegetables from a supermarket were also analysed. The hypothesis was based on the observation that consumers purchase fruit and vegetables from supermarkets and stores on the assumption that they are providing them with sound nutrition. They do not necessarily know the variety or where or how they are grown. Our belief is that despite its often glossy wonderful appearance food today is not delivering the range of nutrient elements that it should. The taste is often very average. We all know that many factors in the production process can affect the ultimate nutrition of the crop, ie fertility management, variety, stage of ripening, post harvest chemical treatment, storage, etc We concentrated on the production end of the supply chain. The soil that the trial vegetables were grown on is a degraded volcanic soil pH of 4.5 low in nutrient elements such as calcium, magnesium, potassium and trace elements. It is in fact in the last stages of the weathering cycle with aluminium and iron oxides and hydoxides evident in the mineral fraction (X-ray diffraction was used to analyse the mineral components). Analysis indicates that the cation exchange minerals are scarce (supported by a low CEC in the soil analysis) and humus is low, meaning that storage of plant nutrients for ready access for plant roots is also low. This soil was revitalised with rock dust(basalt) and specific prescription mineral fertiliser containing calcium, magnesium, potassium, phosphorus and trace elements, a zeolite mineral added to increase the exchange capacity and good quality compost added to increase the biological activity of the soil and to aid in mobilisation of nutrients from the minerals added. It should be emphasised that this was not a replicated plot experiment and the results are only an indication and not a direct comparative study. The trial is however sufficient to illustrate that replenishing a depleted soil with the correct minerals will result in mineral rich foods. A lot more work needs to be done in this area and to expand the nutrient elements to include more mineral elements, proteins, amino acids, phytochemicals, etc. When we examined the analytical results from the vegetables grown on the revitalised soils and the supermarket items mineral levels were often ten times higher on the revitalised soil. Australian soils as many people would know are very old and fragile requiring careful treatment. Our results indicate that perhaps conventional management supplying only a limited number of nutrients through synthetic fertilisers and not replenishing organic matter may not be providing the nutrition that Australian consumers believe to be the case. I believe it was Wm Albrecht that said production levels continued well after quality diminished. Perhaps we are seeing this in Australia at the present time? We hope this limited study will stimulate further research. Results are below: beans tomatoes capsicum silver beet calcium S 40 6.7 4.7 6 O 480 67 84 1600 potassium S 260 200 150 450 O 1900 300 1600 2600 magnesium S 26 10 11 69 O 240 89 700 1700 sodium S <1 2.4 <1 180 O <10 26 20 1800 iron S .6 <.5 <.5 1.4 O <5 <5 <5 9.4 zinc S .38 .19 .13 .57 O 3.4 1.2 2.5 130 mg/kg S-supermarket produce O-organic/revitalised soil I hope this table reproduces so readers can follow the results. Chris Alenson Technica Adviser Organic Advisory Service Organic Retailears & Growers Association of Australia email oas@alphalink.com.au I hope this table reproduces so readers can follow the esults. Chris Alenson Technica Adviser Organic Advisory Service Organic Retailears & Growers Association of Australia email oas@alphalink.com.au To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail