POINTS OF VIEW

Waipa Post, Volume 48, Issue 3471, 26 May 1934, Page 7

POINTS OF VIEW

LETTERS TO THE EDITOR.

RAGWORT AND POTASH SALTS

Sir, —I was more than surprised to read in the Dairy Exporter of the Ist May an article by Mr C. E. Cuming, late editor of the N.Z. Farmer, stating that Waikato farmers have discovered that potash salts are just as effective as sodium chlorate in the destruction of ragwort. In the first place the former is essentially a “killer,” and both are manufactured for their respective purposes. It is only a few weeks ago that I helped to dispel the illusion that sulphate of ammonia is a “killer.” He is a bold man who can state that any manure is a “killer,” or in one season only, because ragwort infested pastures cannot be cleared up entirely of ragwort in less than three years even by sodium chlorate and lime mixture, and as the originator of this treatment, from my own practical experience, I unhesitatingly make this statement. For many years past potash salts and sulphate of ammonia have been extensively used for topdressing, but no suggestion has ever before been made that they kill ragwort; why not, when up to five years ago there was no sodium chlorate or any other cheap and effective method of eradication knciwn. It is very regrettable that irresponsible statements should be issued to farmers until any system whatsoever had been thoroughly tried out. In the case of sodium chlorate and lime treatment, I carried out experiments on my own farm for a full year before making my first official pronouncement of its success, which was given in the New Zealand Farmer, and a month later in the Dairy Exporter. Its success has been fully established all over New Zealand as the cheapest and most efficient system whereby complete eradication and reconditioning of pastures can be carried out. That it is the cheapest method, there can be no question about, because 1 cwt of sodium chlorate is equal in “killing” value to one ton of any other substitute known, for when this is mixed with one ton of lime it yields 21 cwt of the famous 4.75 per cent mixture which has been responsible for clearing up thousands of acres. None of the other substitutes can be broken down in this way bv mixing with lime. They have to be used in the pure state, which renders their cost prohibitive for large scale operations, with this marked difference also that the sodium chlorate and lime mixture does ‘kill” ragwort, whilst substitutes only burn the plant down to ground level and fertilise the roots, the mixture kills them. Let any of your readers try for themselves. Take three plants of equal size—sprinkle one with a few grains of potash salts, another one with sulphate of ammonia, and dust the other once with sodium lime mixture. Mark the plants, and in a month’s time examine the roots. Those treated with potash salts and sulphate of ammonia will be found to be in a healthy, vigorous state, whilst the roots of the plant treated by sodium and lime will be dead. Mr Cuming mentions the case of a farmer who says “the method I used was exactly the same as with sodium and lime, just putting a few grains in the cen tre of the plant.” That is the wrong way to apply the sodium and lime treatment. In all my various articles and pamphlets on the subject of my treatment, I have never suggested only putting a few grains of the mixture in the centre of each plant. Plants require dusting all over, as each leaf is connected with the root system underground, and it would only be the smallest of plants just above ground, that would be killed by a few grains, “injuring is not killing,” and these two words represent precisely the difference between substitutes and my mixture, which does kill. It must be remembered, however, that you cannot kill ragwort until it appears above ground, so therefore in heavily infested distr.cts where it has been allowed to seed, it will take the best part of three years to get rid of it all, arid more than that if the ground is ploughed up without first giving it a heavy dressing as advised in my last pamphlet, because ploughing uncovers seed lying dormant. This has to be dealt with as it appears. Now as to cos t—Mr Cuming glibly states that potash salts cost £lO a ton as against sodium chlorate at £56 a ton, but he omits to state that only 1 cwt of sodium chlorate is necessary to do the same amount of “killing” as one ton of potash salts does of surface burning and root fertilising, so even assuming that potash salts did really kill, taking Mr Cumings’ figures, we find that 1 cwt of sodium chlorate at £2 16s pluls a ton of lime at £l, produces 21 cwt of real killer at a total cost of £0 16s, while 20 cwt of potash salts would cost £lO 10s, thus conclusively showing a saving in favour of the sodium chlorate and lime treatment of £6 14s on 21 cwt. An even more striking example of the cheapness of the sodium lime treatment may with advantage be given. One ton of sodium chlorate when mixed with 20 tons of lime over the same basis of cost would yield 21 tons of the 4.75 per cent mixture for £56 plus £2O, or £76 in all. Twenty-one tons of potash salts at £lO would cost £2lO, thus showing a difference in favour of my mixture of £134 on a 21 ton lot. Finally, as to the cost per acre tor the first main dressing in October—the 21 cwt mixture is sufficient for 4 acres at 51 cwt per acre. The 21 cwt costs £3 16s, therefore the cost per acre is 19s. To top dress 4 acres with 51 cwt per acre with potash -alts would cost £lO 10s, showing, a cost per acre of £2 12s 6d, and a difference per acre in favour of the sodium l'.me treatment of £1 13s 6d. The difference would be more marked still in the case of substitutes costing more than potash salts. I trust that the facts herein given may be of assistance to all those who are affected by ragwort, and serve to d ; spel the fallacy that sodium chlorate and lime mixture is an expensive treatment, when actually it is many times over cheaper than any method yet discovered, and absolutely reliable. Its efficiency has been approved by Governmental and every other authoritative source, including your own columns, through whose assistance the method has now come into use throughout New Zealand. If sodium chlorate were .to cost £IBO per ton it would be cheaper than potas-

slum salts at £lO a ton, because, y cwt of sodiulm chlorate at that price would cost £9, and with a ton of lime £lO, yielding 21 cwt as against £lO for 2*o cwt of potash salts.—L am> etc W E. CAYLEY ALEXANDER. Pio Pio, 25/5/34.