Technical
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All things are poison, and nothing is without poison; only the dose permits something not to be poisonous
high quality turf can be achieved with meagre resources and inputs. In the second of this series of articles, I
referred to the biological aspect of turf management on numerous occasions. The biological aspect covers many facets - some like to add biostimulants, others may use compost teas, and even specific strains of bacteria or fungi to serve a specific purpose. There are demonstrated results of this type of management regimen at several venues, so it is certainly not without foundation; however, for every success story, there is a failure. This path of biological turf management is extremely complex, and I do not think that science has all of the answers as yet - I’m afraid that it is not a simple case of adding a biostimulant and being done with it - successful biological turf management requires an ‘all in’ mentality, rather than a monthly application of an ‘elixir’ on top of an already chemically overburdened soil.
I think that it is fair to say that science is not
yet in a position to provide us with quantifiable, repeatable and predictable results, though there are a number of basic principles which are proven to aid with microbial turnover and acquisition of mineral nutrients from the soil, and I am a firm believer in adopting them. In terms of fertilisers, it’s all in the amounts,
The advent of modern sewerage systems has opened up the phosphorus cycle, whereby what could be considered as a valuable, renewable phosphorus source is lost to the sea
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In the early part of the 20th Century, each year in China more than 182,000,000 tonnes of human manure was collected in cities and villages - 450 kilogrammes (900 pounds) per person per year. This was good for a total of 1,160,000 tonnes of nitrogen, 376,000 tonnes of potassium and 150,000 tonnes of phosphate, which was returned to the soil. In 1908 Japan, 23,850,295 tonnes of “humanure” was collected and given back to the soil
130 I PC JUNE/JULY 2015
and of what we apply. Yes, some forms of fertiliser are more damaging to soil biota than others - many that make every effort to protect the soil biota will often quote salt indexes when talking mineral fertilisers. I, on the other hand, prefer to focus on the quantities first and foremost. I believe that the role of soil biota mining for nutrients is often underestimated, and I believe that excessive levels of fertilisation suppress several natural phosphorus acquisition mechanisms, amongst other negative effects. As I remarked in the first in this series of
articles, mycorrhizal acquisition is often found to be redundant in soils where excess levels of phosphorus are present - I would also add the fact that applications of inorganic phosphorus can repress phosphatase enzymatic activity which, in itself, is a product of microbial activity.
In the last article, I also remarked about the
vagaries of soil testing, with several different soil testing methodologies being commonplace, and more benchmark figures in place than I could care to recite. I have long questioned the ‘recommended’ guidelines and, in recent years, have adjusted my own fertiliser methodology to fall in line with MLSN (Minimum Level of Sustainable Nutrition) guidelines. My philosophy is to apply the minimum amount of
fertiliser possible, whilst achieving the desired result.
This is achieved on a ‘little and often’ basis - all in an effort to ensure that at no point in time is there an excess of any nutrient over and above what the plant requires, thereby avoiding the ‘peaks and troughs’ that can be so disruptive to the microbial biota and their acquisition mechanisms. Whilst the path that I now follow may seem
like the new ‘latest fad’ in terms of fertiliser programming, I would have to say that this ideal is far from new, it is just the terminology that has been given to a long acknowledged process of ‘spoon feeding’. I have already discussed Shelford’s Law of
Tolerance in the second in this series of articles, but perhaps it was the medieval alchemist, Paracelsus (1493-1541) who said it best: “All things are poison, and nothing is without poison; only the dose permits something not to be poisonous.” In short, dose rate matters, and overdosing is
often more problematic than a limited supply. The above falls in line with the basic principle that all living organisms should maintain a balanced nutrient supply - nothing in limitation, or excess. Throughout this series of articles, I have referred to the use of various forms of excreta,
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