LITTLE KNOWN FACTS ABOUT WORMS AND SOIL You might not consider 50 worms per square foot a large population. But if the worms average a weight of 1.5 gram each (conservative), then there will be 75 - 100 grams or close to 4 - 5 ounces per square foot. Let's say they "eat" half their weight in soil daily. This actually translates to over 8 tons per hectare. In a healthy soil, the presence of worms encourages the development of a biota which will reach a mass six times that of the worms. Therefore, in a hectare containing 8 tons of worms, there can be another 48 tonnes of biota, which amounts to no less than 54 tonnes of life, per hectare, beneath the surface - far in excess of what you will ever have walking on top of it !In illustration of this, imagine you are running beef cattle on your very fertile pastures, and you can run at an exceptionally high stocking rate of five beasts per hectare. On the fifty-four tonnes of undersoil organiclife, you have only maybe two or three tonnes of oversoil four legged organic life Remember too, that these worms will eat half, or more, of their own weight daily and, as they do, will till, aerate and fertilise at the rate of nearly4 tonnes of soil per hectaredaily. This is 1,400 tonnes of soil per haper year soil which becomes more moisture retentive and more productive as the years pass. However, worms are not able to work for you 365 days of the year, but only when the soil is sufficiently moist. But, because worm-populated soils wet more quickly and more deeply, and retain their moisture longer, the better it gets, the better it gets. A good, or even better than average, perhaps even a bumper wheat crop is around four tons per hectare. In Europe, four times this yield can be achieved. There are a number of factors influencing this figure, such as protein levels (hard or soft wheat), quantity and reliability of rainfall, but it is significant that field worm populations of 2000 worms per m2 have been recorded in Europe. It is partly for this reason that England, which has a land area which can be fitted into Victoria several times, (the next to smallest Australian state) can sometimes produce more wheat than the whole of Australia.
COMPARE ! Here are some crop/pasture yield comparisons which were influenced, by a variety of factors, but the common thread is earth worms or their products. Orchard Dr. Judy Tisdall at the Tatura Research Station (Victoria, Australia) conducted a trial on a peach orchard. She took counts of the soil worm population and found an average of 150 worms per square yard before the trial commenced. Average peach yield per acre over the harvest season was 16.5 tons.She mulched the orchard with 5 tons of sheep manure and straw per acre and over the three years of the trial the worm population increased to 2000 per square yard. The yield of peaches increased to nearly 74 tons per acre per season.(Source: Tisdall J.M. (1978) “Ecology of earth worms in irrigated orchards”, in “Modification of soil structure”. Edited by Emmerson, W.W., Bond R.D. & Dexter, A.R. Wiley, New York).
Horticulture A joint operation by the US Agency for International Development and the Canadian International Development Centre. They found that worm-populated soil when compared to similar soil without worms disclosed the following increases in productivity: Peas .................. 300% Corn.................. 250% Potatoes ........... 135% Rye ..................... 64% (Source: ”Wall Street Journal”, December 19, 1974).
Dr. Thomas J. Barrett, an American of remarkable and various talents and a pioneer of the practical uses of worms in the 1930s and 1940s, achieved quite significant results. He reported harvests of potatoes of 30 tons per acre and onions of 14 tonnes per acre.(Source:‘Worms for Ecology and Profit’, Vol.1, by Ronald Gadde Jr.). PastureIn New Zealand pasture soils, after the introduction of earth worms (by the sod transfer method which can be seen in David Murphy’s book Organic Growing with Worms at the website https://brightsunpublishing.com/), researchers have found an immediate increase in productivity, usually to the order of 70 per cent, reducing in time to around 25 per cent, providing the numbers of earth worms are kept at least constant. (Source: Stockdill, S.M.J., (1982) “Effect of introduced earth worms on the productivity of New Zealand pastures”).
Agriculture Canberra City Government, (Australia) in agricultural trials associated with a worm-driven waste management facility, found that the application of vermicast to broadacre lucerne on a property “Illourie” at Boorowa at the rate of 75 pounds per acre produced an increase in dry matter yield of 15%.(Source: Gerard Gillespie in “Vermiculture as Waste Management”). Viticulture A trial by John Buckerfield and Katie Webster of applying vermicast under vines and then mulching heavily with straw and/or shredded paper increased the yield of Pinot Noir by 55%. On another site Chardonnay vines produced 35% more. In neither case was there any reduction in juice quality. (Source: “The Australian and New Zealand Wine Industry Journal”, February 1998).
Personal communication with John Buckerfield discloses that “yield increases continue to be noticeable” five years later. (John Buckerfield, EcoResearch, 92 Angas Road, Westbourne Park 5041, Australia). Different species of worms are constantly found working harmoniously together, despite their functions and behavior differing slightly between species, even though, basically, all tunnel through the soil. This tunneling results in soils of differing strata being mixed together and quantities of this mix being deposited on the surface as castings. In time, the surface deposit builds up as a thick stoneless layer of enriched topsoil.
MAKING TOPSOIL In Europe, and in the more temperate parts of America, over one hundred years, worms can deposit a 200 mm thick layer of topsoil. Australia, because few if any, of the indigenous worms surface frequently to deposit their castings, the surface rate of buildup due to worms would be closer to 25 to 40 mm. (Source: Handrek K.& K.E. Lee, Worms for Gardeners and Fishermen, CSIRO). This difference would be due not just to the different species of worms but also to Australia’s harsher environment, the sunnier, dryer climate, resulting in an uncomfortably higher surface temperature causing moisture depletion and, also, the ancient nature of the soil. Agricultural soils of the world lack organic matter (OM).In monocultural farm systems – where the same crops are produced every year in the same soil - the average OM content of the top soil is under 1%. Some countries are even worse than that !Soils capable of supporting naturally renewable fertility must have an OM of at least 5% but some organic growers can even boast OM as high at 15% - 20%. OM includes not just vegetative matter, but also the biota. However, not only is the OM depleted and deficient, the soils themselves are also deficient in minerals. This has occurred not only because of the ravages of time, but latterly, over the past 100 years, through our flogging the soils to constantly to be more productive. In Australia, a major aggravation of mineral deficiency in soil is that the landmass missed the last Ice Age and the soil remineralisation and refurbishment which occurs during that period.
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