The merits and pitfalls of biological farming
Biological farming is a catchphrase that is bandied about by some fringe fertiliser companies and consultants.
They often radically reduce the inputs of conventional NPK fertiliser products and introduce ideas and products that supposedly enhance soil biology (earthworms and microorganisms) and improve the nutrient value of plants. Improved plant and fruit brix levels, lower weed and pest infestation, a lessened dependence on chemical sprays and building up of soil carbon levels are also claimed.
Biological farming differs from organic farming, as growers can still use chemical sprays when needed, and some of the fertilisers used are artificially manufactured, whereas under organic farming, only registered naturally occuring products such as reactive phosphate rock (RPR), elemental sulphur, potassium chloride, animal manures and composts that meet certain standards can be used. Conventional synthetic chemical sprays are a no-no.
On the face of it biological farming sounds too good to be true and it’s understandable that farmers and growers are tempted to look at what these fringe companies are promoting.
Biological fertiliser companies take their lead from overseas ‘experts’ who have come to New Zealand promoting their ideas through seminars and workshops, such as American, Arden Anderson, who is author of a number of books related to agriculture and also is a practitioner of alternative human medicine. Expat Kiwi musician Graeme Sait, has set up a successful business called Nutri-Tech Solutions across the Tasman in Queensland and has also written several books, again overlapping agriculture and human nutrition.
And American agronomist, Neil Kinsey, is the author of the book Hands on Agronomy. Kinsey’s approach to soil fertility rigidly embraces the ideas of Dr William Albrecht who in the 1930s 40s and 50s researched the deleterious effects of high NPK fertilisers on the uptake of other elements, and their negative effect on plant, animal and human health. Along with fellow researchers Drs Bear and Toth they came up with an ideal ratio of major cations calcium, magnesium, potassium and sodium, suggesting they should make up 68 percent, 10-12 percent, three to five percent and one to two percent respectively of the base
On the face of it biological farming sounds too good to be true and it's understandable that farmers and growers are tempted to look at what these fringe companies are promoting.
saturation percentages from soil tests.
This base saturation ratio (BSR) approach to soil testing for crop nutrient levels was later trialled in the United States against the standard sufficiency level of available nutrients (SLAN) approach using parts per million (ppm) of nutrient levels (Ministry for Primary Industries’ Quick Tests are based on this), and it was found the SLAN approach was a better predictor of crop responses.
Anderson is a critic of the most common fertilisers we use here such as urea, diamonium phosphate (DAP), superphosphate and muriate of potash (potassium chloride), claiming the latter in particular was the worst possible fertiliser for soils. This is all music to much of the alternative fertiliser industry who seize on the supposed harm caused by conventional fertilisers, selling their brands of biological fertiliser products or blends which, when analysed on their nutrient value, are often highly
inflated in price compared with an equivalent blend from one of the two major fertiliser companies, Ballance or Ravensdown.
A common feature of these biological farming salespeople is that they generally lack any formal qualification in agricultural science and are dismissive of historical scientific research done in NZ or are very selective in any research they do quote.
In the NZ Journal of Experimental Agriculture 1987, Vol 15, there was a paper investigating the effectiveness of a commercially available enzyme-based soil conditioner on sports turf at Tonga Park and Carisbrook. The researchers reported:
“The claims made for the effects of the conditioner are impressive. If proven effective in ‘activating soil bacterial activity’ and ‘increasing deep water penetration’, this product would indeed be a valuable tool for sports ground management as well as in agriculture generally. This trial has tested the efficacy of the conditioner using a wide range of soil chemical, biological/biochemical and physical criteria and found no evidence to support these claims. There was no visual field evidence of any response to the conditioner… Our results support those of previous studies.”
In a critical review of the value to agriculture of microbial fertilisers, activators, and conditioners, Duigan (1979) referred to them as “miraculous cure-alls” for any soil or crop problem, and stated that ‘their mode of action was usually shrouded in mystery.He found no replicated test data to support manufacturers’ claims.
Duigan’s comments can probably be echoed when we consider the current fertiliser scene in NZ where so-called fringe fertiliser companies sell their products whose “mode of action is usually shrouded in mystery”. The fertiliser industry is still a buyer-beware industry and there are many millions of dollars wasted each year on useless or expensive products.
Most of the biological farming philosophy involves using some form of lime (calcium), phosphate in very small quantities if at all, trace elements and supposed biological stimulants such as humus, fulvic acid, sugar, molasses, compost teas, silicon, compost, rock dust, zeolite, probiotic enzymes and specific strains of bacteria or fungi. From what I have observed, it is usually the lime or trace element component in biological mixes that gives a response, as it is these that nutrients the mainstream fertiliser companies have not historically promoted as being that important. Lime and trace elements are vitally important, but so too are the major elements nitrogen, phosphorous, potassium and sulphur, and these need to be applied in the most cost effective way, sourced from whichever company is the cheapest. Biological responses are very unpredictable and can be quite significant, but biology still needs the nutrient base in the soil to work with.
Having good drainage and soil structure (plenty of oxygen), good organic matter (humus) levels, a good soil pH and good levels of all 16 of the essential macro and micronutrients should give soil biota the best chance to work any magic.
CPAg, Member of the Institute of Professional Soil Scientists