EXPERIMENTS WITH MANURES.

Otago Witness, Issue 2059, 10 August 1893, Page 6

EXPERIMENTS WITH MANURES.

When Mr F. J. Cooke, an extensive English farmer, told the members of the London Farmers' Club, that on his farm a dressing of 3cwt of nitrate and 3owt of superphosphate per acre failed to produce even a moderate crop of barley, but when he added to the mixture 2cwt of muriate of potash, he obtained a crop of 54 bushels per acre, the statement occasioned some surprise, as the nitrate and superphosphate are favourite dressings. Mr Cooke explained, however, that he had tested the wants of the soil and of the crops by trials carried out on small plots using the following elements of plant food : — Nitrogen, phosphoric acid, potash, and lime, one plot remaining unmanured, another having all the ingredients, whilst upon the other plots each ingredient was in turn omitted. The results clearly showed the necessity for the addition of potash. Last year a series of experiments on similar lines were carried out by Professor Gilchrist of University College, Bangor, Wales, with the view to ascertain the effect and comparative economy of various dressings of manures applied in growing turnips. The following manures were used : — Superphosphate, 26 per cent, phosphate of lime made soluble ; basic slag, 37 per cent, phosphate of ..lime ; nitrate of soda, nitrogen equal to 19 per cent, ammonia ; kainit, 12 per cent, potash ; phosphoguano 35*40 per cent, phosphate of lime, 34 per cent, ammonia ; gypsum ; salt. The land was divided into 11 plots, each receiving different treatment. Plots 1 and 11 got no manure, and they gave crops weighing 13 tons 19cwt 141b and 14 tons 71b respectively. Plot 2 was dressed with scwt superphosphate and lewt of nitrate of soda, at a cost of £1 4s 9d per acre. This produced a crop of 24 tons 13cwt 211b. The scwfc superphosphate applied to plot 3, at an outlay of 14s 9d, returned a crop of 23 tons 421b. To plot 4, 2cwt of kainit were added to the dressing of plot 2, at a total cost of £1 9s 9d, and this gave a yield of 25 tons lewfc 71b. The fifth plot received an application of 4cwt phospho-guano and 2cwt kainit, at a cost of £2 4s, the yield of crop being 26 tons llcwfc 71b. The effect of using kainit along with the phospho-guano was shown by the result of plot 6 to be worthless. The 4cwt of the latter manure alone — applied at a cost of £1 19s — gave a heavier crop (26 ton? 12cwt 491b) than was obtained by adding kainit. The weightiest crop of the whole series was on plot 7, which was dressed at the moderate outlay of £1 3s 9d with 2cwt superphosphate, 4cwt basic slag, and lewt nitrate of soda. The yield of this plot was at the rate per acre of 28 tons 17cwt 141b. At a cost of £1 4s, plot 8 was dressed with 7cwt basic slag, and lewt nitrate of soda. The crop here weighed 27 tons 4cwt 1051b. On plot 9, scwt superphosphate, lewt nitrate of sods, and 2cwt salt, costing £1 6s 9d, gave 26 tons 16dwt 911b, and on plot 10, scwt superphosphate, lewt nitrate of ooda, and 4owt gypsum, gave 25 tons llcwt 421b The most notable resalts of these experiments, Professor Gilchrist adds, are : — 1. That basic slag is the most suitable manure for this land, as shown by the excellent results on plot 8. 2. The results on plots 2 and 3 show that the addition of lewt nitrate of soda to a phosphatic manure for swedes on this land materially increases the crop. 3. If we compare plot 2, where no kainit was applied, with plot 4, where kainit was applied, we find that only a small increase results from the addition of kainit to the other manures, and if we compare plot 5 with plot 6 we find that we have no increase whatever from an application of kainit. 4. If we compare plot 2 with plot 10, it is found that the addition of 4cwt of gypsum per acre does not materially increase the crop. 5. The comparison of plot 2 with plot 9 seems to indicate that salt will produce a considerable increase in the amount of the crop. 6. The result with the most expensive manure — viz., phospho-guano — are not satisfacfactory, better results being got on plots 7 and 8 with ether simple manures at a much less cost. Particulars of these experiments are given as showing lines on which farmers may in a small way conduct trials for themselves, and this is

the time of year when they may be conveniently undertaken in the case of cdro, grass, alia mangels, and of turnips a little later dn 1 . ' Another direbtion in which 1 a great deal of useful information may be obtained experimentally is in the change of seed, which is in sotoe bases habitually practised, while' in others it is too much neglected.