TOP DRESSING.

Manawatu Herald, Volume L, Issue 3945, 21 May 1929, Page 4

TOP DRESSING.

LECTURE BY PROFESSOR SCRIVENER. (Concluded from page 3). applied into the produce taken from the land, such as meat, milk or wool. 'The correct procedure of course has ‘been to replace what was taken frojm the soil as they went along and to put on proper manures in the proportion of the returns desired. The extent of economical manuring was a matter for the individual farmer, the soil and local conditions. It was true to a great extent that a fanner could only get back what was put into the" soil. The better the physical condition of the soil, the better the drainage, warjmth etc., the better the medium for converting the manures. Therefore it was the best policy to limit the expenditure in top dressing sandy soil. In any case, a fanner with a limited amount of money for top dressing should be sure to top-dress his best paddocks first as he would, always get a better return from his good paddocks than from the poorer one, but, nevertheless this did not mean that he was to let the poorer land on his failm- go back. From a chemical point of •view, there were eleven chemical units or elements which plants required in appreciable quantities and many more which were required in smaller amounts. Of the eleven only four could ibe found in common practice that gave any return when increased in the soil. These were phosphates, potassium, nitrogen and calciulm or lime. ‘These four elements served quite different .functions and were not interchangeable. If a property was deficient in phosphates no amount of potassium would do it good and vice versa. Dealing with each of the four units separately, Mr. ‘Scrivener said that phosphates had many and varied applications. The two main ones used in New Zealand were straight super phosphate or mixed or basic slag. It was practically impossible to say which was the best. If anything super gave a quicker return than slag, but slag lasted longer. Chemists could not distinguish much difference between straight or basic super but this was a matter they hoped to be able to tackle at Massey College when they had a few more facilities. At the present time the experience of farmers with these manures was very valuable and would Ibe appreciated by the ■College. At the college last year experiments were started to compare super and .slag. Paddocks had been set aside and treated with the two manures and they will receive annual treatments and it is hoped by this method to be able to discover some tangible difference. Air. Scrivener referred to the rumour that was current among farriers to the effect that super created a sourness in the ground. Thero was no proof of this at all and they could only rely on their own experience in this matter. His advice to the farmers concerning topdressing was: If you find that super gives good results stick to it and "don’t bother trying anything else, provided the price is iright. If you haven’t tried super, do so. Referring to the Manawatu district, Mr. Scrivener said that in this locality phosphates were a first essential. As long as some phosplmtic manure gave good results there was no need to try anything else, but the time would come, as it already had in other districts, when the farmers would have to look to other manures to increase the stock carrying capacity and fertility of their lands. In this connection potash was found to give the best results on light or peaty soils. The>re was a definite response to bopdressing both these lands with patash. It gave a greater vigor to the growth and stimulated clovel’growth It was difficult to actually see the improvement effected by the applicationl of this manure and it was likewise difficult to measure but they were now experimenting at Massey College with a view to being able to show some definite improvement and it was hoped to have developed some scheme in a very short while. Mr. Scrivener said that in this district, where the farmer Was in a position to go beyond phosphatie manuring, it would be very advisable for him to try potash. If it was tried and there was no apparent good result, they should not be disheartened. Live it a good trial, lie urged, try 2cwt. on a small strip and a betterment in colour and clover development is almost sure to result. Thirty per cent, potash salts was the best, grade to use. Touching on nitrogenous manuring, Air. Scrivener said that this top-dressing had had a great fillip of recent years owing to the production of synthetic ammonia from the atlmospheire. If the farmers were not already considering whether nitrogenous manuring iu sulphate of ammonia had a stimulating effect on the rate of growth of grass they soon would because it was found to he very considerable. Soon after application a higher growth of highly productive value resulted. The growth was highly nutritious and therefore had the effect of increasing production. Its application, however, presented one or two minor difficulties. Owing to the amount of growth resulting grazing control was necessary and many of the smaller fanners were not in a position to take this matter up as it called for smaller paddocks, more water, and possibly the use of a mower. Experiments with nitrogenous manures conducted so far showed that it iwas particularly valuable for bringing forward as much as several weeks, an early spring growth. The top-dressing if applied in the summer months was found not to

give the same good results but applied in latei sunffWcr iSlhad Itlie effect of lengthening the period of high production vary considerably. Air. Scrivener was unable to’ say just how economical the treatment was. Tho size of the herd would be increased and good grass would grow ■lmt smaller paddocks would be required of such dimensions that the helrd would graze down a 4 inch growth in one day at. 12 cows to the acre. In other countries where nitrogenous manures had been adopted the stock carrying capacity had doubled. If that could be done here then the fartmers could afford the extra expense that would be involved as they would receive an' adequate return. The chief thing to remember were small paddocks, good grasses, and control of grazing. Liime manuring said Mr. Scrivener, has been the cause of a good deal of discussion and is a controversial topic. Lime was required for two purposes. It was a plant food the same as phosphates and potash and it was also required to neutralise sourness in the ground. Lime also improved the texture of the soil by reducing the sticky properties of clay. The lime of the soil was constantly being depleted cither by the action of the rain or in the products of the land,-such as milk. It had been found that many soils responded to an application of lime yet this fact was difficult to prove in New Zealand. Farmers would find that they would get just as good results from phosphates as from li/me. It had been considered that some of the breeding troubles were due to an absence of lime in the soil, but this had not yet been proved. Research work was being instituted in this direction, though, and as .soon as Alassey College had anything definite to go on it would be passed on to the farmer. In dry weather a paddock top-dressed with lime was frequently found to he greener than other pastures. If •farmers desired to give lime a trial they should give it a fair trial. Mixed with super it was put on somewhere in the vicinity of 301bs. to the acre and this could not be said to be a fair trial. A paddock should be selected, cut up into two and one half treated-with a ton of lime to the acre and the other half with super or some phosphatie manure. A careful watch should be kept for colour, clover and whether stock preferred either pasture. If no good resulted then the farmer should not bother further with it. Lime application was one of the most difficult problems they weru faced with at present. Nearly all soils showed that they required lime. In Europe to-day similar soils to those of New Zealand responded visibly to lime treatment yet there was almost a lack of visible response here.

In conclusion Professor Scrivener said he would like to hear the experiences of any local or district farmers in connection with top dressing. At Alassey 'College they were carrying out laboratory work chiefly and the field experience .of the falfimers would greatly assist them in their research work in connection with top dressing. He would be pleased to answer any questions anyone eared to put to him relative to farm manuring. In answer to a question Air. Scrivener said that 2cwt. of potash of the 30 per cent, grade should be used to the acre, or. equivalent quantities. At the conclusion of his lecture Professor Scrivener was thanked by Air. Ross for his interesting and instructive address and lie was accorded a hearty vote of thanks. Prior to returning to Palmerston North Air. Scrivener made an inspection of Air. R. ,J. Thompson’s property, in Baker Street.