PHOSPHATES AND LIME.

New Zealand Journal of Agriculture, Volume XII, Issue 3, 20 March 1916, Page 217

PHOSPHATES AND LIME.

SOME FARMERS’ EXPERIENCE.

B. C. ASTON, F.I.C.,

Chemist to the Department.

In previous issues of the Journal I . have endeavoured to show that New Zealand soils are usually so deficient in Lime that phosphates, especially superphosphate (which is acid in . reaction), benefit, by being mixed with - either lime or some phosphate containing lime in excess, such as basic slag or bonedust, or even by using basic slag by itself. The following selection of extracts from letters received from farmers in connection with the advice given to them by the writer (through the Fields Division) regarding the manurial treatment of their land contains matter of general interest and . instruction bearing on this subject: — A Stirling (Otago) farmer reports : The manurial treatment advised namely, 2 tons of lime per acre, with a liberal dressing of guano — have found very beneficial for this class of land. On ground that I treated according to .your directions I grew swede turnips up to 25 lb. in weight; on the same ground that was not treated with lime, &c., there were none that would weigh more than 6 lb. The same result was noticeable on all other crops treated. ' ' ; - A farmer at Awarua Plains (Southland) writes : j Regarding advice as to manurial treatment of soil for grass : The paddock treated was 15 acres. It was ploughed out of oat-stubble'at the end of May and. early June, cultivated and rolled 10th to 16th October, limed with 9 cwt. burnt crushed lime on the 17th. Owing to rain it was not harrowed until the 20th. The grass, with 2 lb. of rape, was sown on the'3rd and 4th November and harrowed, immediately (10 cwt. grass-manure sown with grass). Twenty cows were turned in on the 23rd January, 1914. It grazed fairly well all summer, but in winter' had a red unhealthy appearance. It was top-dressed with 2 cwt. basic slag on the 26th July, with simply marvellous results. Twenty cows were put on on -the 10th October, . and although they were on it almost continually in the daytime the. growth of clover was so luxuriant that we fenced off about 5 acres , and cut it for hay. It was fenced off on the nth January and cut on the 15th February, giving, although the weather was very unfavourable, about 2 tons of hay. I think it worthy of mention that one width of the drill was left un-top-dressed, and the rest of the paddock (1 acre) was top-dressed with kainit, 2 cwt. . I could see nodifference ' between the untreated strip and that on which the kainit was put —at least not during the summer. I can see a difference now, but hardly traceable. The part treated with kainit was like a saved paddock, the stock not touching it till late in the season. I think lam within the mark when I say the ground treated by your advice will carry three cows for one on untreated ground. You advised 1 ton lime and 5 cwt. slag. Had I used these quantities no doubt the result would .be still more marked, but I am well pleased with the resultswith the lesser quantities, and am very grateful to the Department for the advice. The following is the report of a farmer at Lichfield,. Waikato : With respect to slag and superphosphate on pumice soil Consequent on your statement that basic superphosphate was but ordinary super, with 15 per

cent, of lime added, coupled with the fact that our experimental use of lime had been absolutely resultless, we decided not to use basic super. The failure to do so experimentally was perhaps a pity. We have, however, as advised by you, used the mixture of 1 cwt. superphosphate and 2 cwt. basic slag per acre, and the results would seem to prove that the value of both is increased by the mixing. In fact, in some cases slag seems of little use unless applied in conjunction with super. ■jA-A . -'■ ■ ■A? t -AM L-i AT '■ s "* i kA- ••<> )’

In April, 1913 (before receiving advice), we applied the two separately, but inNqual quantities, as a top-dressing. The spot chosen was a gully-bottom that was growing tussock, fog, and white clover. By close inspection the clover was just discernible among the fog. On the coming of spring the result of the super, dressing was startling. The white clover took complete possession, the fog disappeared, and by summer there was as fine a showing of leaf and seed-head as one could desire ; whereas the only result of the slag dressing was that the grass and clover both became a slightly livelier green, no increase in growth beyond the ordinary being noticeable. It was observed, however, that when the stock had access to it they preferred that portion dressed with slag to that which had received no dressing at all, ' though certainly not in preference to the super.-dressed portion. For a comparative illustration of the results of the slag - and - super, mixture as compared with the super, alone I will report from an experimental plot of grasses and clovers established by my brother on the Bth October, 1913. Although the clovers in the -dressed portion of the plot were quick to establish and continuous in growth, it was noticeable that in the slag-and-super. portion they had slightly the advantage from the first —an advantage which they have distinctly maintained to the present (May, 1915). The difference was even more marked with the grasses. In fact, the grasses in the super.-dressed plot did little better than in the unmanured part alongside. The slag and super., however, distinctly encouraged the grasses, and was only beaten by the rye in the blood-and-bone portion. I might add here that the clovers in that portion were comparatively a failure. ... ■ . - , . With respect to slag and super, for turnips, no such careful experiments have been carried out as would give valuable data. Our experimental plot in this crop was quite resultless. After an elaborate system of manuring no one section showed better than another, or little better than the unmanured section. It was, however, our first trial with turnips (swedes), and it taught us that the best and most necessary preparation for any manuring on pumice soil is the thorough working of the soil, concluded with a final firm rolling. We have this year a portion of a swede paddock sown with slag and super., and a portion sown with super, and Island phosphate. So far there is no visible difference in growth, but it was distinctly seen that germination in the slag-and-super. portion was quickest and best. < A farmer near Palmerston North writes I consider I had good results from the fruit-trees I treated as you recommended with 1 lb. each bonedust, superphosphate, and seed gypsum, and J lb. sulphate of potash, forked in round each fair-sized tree. I used it on peach-trees only, and 'the fruit was well grown, and the trees put on more growth and showed a healthier appearance. The early peaches were well formed and of very good colour and quality; the late peaches were well formed, but not so good in colour, due, I think, to the cold dull weather ,in the autumn. I hope for better results in the coming season. . A farmer in Waiau (North Canterbury) reports t as follows: — ! For oats you advised drilling with the seed, 1 cwt. of superphosphate and f cwt. island phosphate per acre. This advice was acted on, and gave first-class returns. The mixture was -drilled in with.the seed on a field of 12 acres on the 16th September, 1912. In January, 1913, there was stacked from the field of oats three 6-yard stacks estimated to contain 40 tons of oat-sheaves. During May, 1913, these stacks were threshed, and yielded at the rate of 80 bushels per acre. For your information I wish to add that in 1911 this field produced one 6-yard stack, which threshed about 34 bushels to the acre ; this crop was grown without manure. On the 25th September, 1914, you advised the use of superphosphate, bonedust, and basic slag in equal parts for rape and turnips. This advice has been followed and has given the greatest satisfaction during the past dry summer.

The following report is from an Opuatia (Waikato) farmer :

Regarding manorial treatment recommended by your Department: I topdressed with slag as advised, applying 6 cwt. per acre, except for a small portion which received 2| cwt. per acre, and another portion unmanured. The manure was applied in January, 1914, and for some time I saw no result, partly on account of the dry weather. lam now (May, 1915) well satisfied with the result. That which had the 6 cwt. of slag came away splendidly in the spring, being of a much darker green than the 2 J cwt." piece, and thickening up much more quickly. Although 1 it has had no more top-dressing since, it is a much better sole now than ever it was, and comes away well when closed up, excepting of course the unmanured piece, which shows signs of running out, and is much inferior in every way to the top-dressed grass and clovers. The 2 J cwt. piece does not grow as quickly as the 6 cwt. portion when the stock are off it, and the slag did not appear to act as quickly on it. A Hukunui (Eketahuna) farmer writes I might mention that I ploughed in a light crop of oats on scrub land and then sowed down in grass, using basic slag as you recommended, and the resulting sward of clover and grass is the best I have had.