ON THE LAND

Taranaki Daily News, 28 April 1934, Page 12 (Supplement)

ON THE LAND

manures and manuring KEEPING UP SOiL FERTILITY POTASH AND PHOSPHATE ADDRESS BY MR J. M. SMITH “The necessity for manuring . is brought about by the gradual depletion of the plant foods in the soil as the result of our farming operations,” remarked Mr J. M. Smith, of the Fields Division of the Agricultural Department, m prefacing his last talk over 2YB, New Plymouth. “In all virgin New Zealand soils,” he continued, “there is sufficient plant food to ensure growth, although that growth will be governed largely by the quantities of plant food present, or, in other words, by the fertility of the soil, as exemplified by the variation from our heavy forest on our better country, in the poor birch country and, lower still, in the stunted scrub lands and tussock country. While there are other factors regulating these various growths it is generally recognised that the fertility factor is the main one. “In nature’s plan there was a gradual increase in soil fertility as time went on, as nothing was removed from the soil and actual plant food additions were made through the plants taking in certain foods from the air and these in turn being added to the soil through the rotting vegetation. With the advent of man, however, the position was largely reversed, and with our export of wool, meat and. butterfat a gradual depletion of the fertility of the soil commenced. The rapidity of this depletion naturally depended largely upon the class of farming and the ability of the farmer. With dairying the rate of soil exhaustion is much greater than, is the case with grazing, while the variation within the dairying business itself is great. For instance, there are farmers who, through ability, , are to-day taking 3001bs. of butterfat per acre off their farms, while the average butterfat return for New Zealand is 801bs. per acre. Thus it will be seen that the standard of fertility of our individual farms to-day will depend upon (1) the greatness or poorness of the natural fertility before the use of the axe or plough, (2) upon the rapidity of depletion of fertility since then dependent upon the type of farming undertaken and the ability of the farmer to produce, and (3) the attempts that have been made by the individual farmers to replace the fertility by the use of manures. VARIATION IN RESULTS “These few brief facts explain very largely why there is such a variation in manure results at times between one farm and another, or even between one paddock and another, and they also explain why crops grown by the early settlers were so much better than many of the crops grown to-day. These crops had the advantage of the natural fertility of the soil, a fertility that no matter how hard we try to imitate we fail in the trying, and while these early settlers to-day sit back with pride and relate the crops they used to grow (probably weighing a little more in the relating), they should finish up by apologising to the present farming generation for having removed some of nature’s gifts and handing on to posterity a much depleted soil. As an indication of the rate of depletion might be cited the fact that a 3001 b. butterfat cow in the consumption of 20 tons of grass yearly takes in nearly 601bs. of phosphoric acid (equal to 3cwt. of slag), and of this amount approximately 201bs. is lost to the soil in the form of milk. “Further it might be stated that a three-ton crop of hay r< moves roughly lOOlbs. of nitrogen, lOOlbs. of potash and 301bs. of phosphoric acid, a 60-ton mangold crop 2601b5. of nitrogen, 5001bs. of potash and lOOlbs. of phosphoric acid, and a 40-ton swede crop 2001bs. of nitrogen, 1601bs. of potash and 501bs. of phosphoric acid. Of course the. bulk of these crops goes back to the soil in the form of manure, so that the actual drain is nothing like so much as the figures indicate', unless the crops are removed and fed elsewhere. These figures indicate very clearly to us the necessity of feeding back on to hay and ensilage paddocks the crops harvested from them. FACTORS AFFECTING FERTILITY “Besides actual plant foods there are other factors that influence the fertility of a soil. These are: (1) the mechanical condition and (2) the biological condition. In connection with the first it is obvious that a soil to be fertile must be well drained, for, although a wet swamp may be rich in plant foods, it may be poor in production until it is drained. Again a pure sand may be rich in plant foods, but mechanically poor as far. as production is concerned. With regard to the biological condition of the soil unless the soil is alive with beneficial bacteria the soil may be low in fertility. Bacteria have the power to liberate plant foods lying dormant in the soil and in the case of legumes such as lucerne, clover, etc., the presence of the nitrogen fixing bacteria in the soil is the very life essence of the plant. Here again to be in good biological condition the soil must be well drained and sweet. The use of lime to bring about a good condition for bacterial activity is often necessary. “Improvement in plant food in the soil can be brought about in two ways: (1) by the addition of substances containing the plant food and (2) by the addition of substances which have the power of liberating plant foods already in the soiL In the case of the former, artificial fertilisers and farmyard manure are used, while at times green crops are ploughed in for this purpose. A complete analysis of our soils would reveal the fact that there are sufficient plant foods in our soils for many years to come, but a large proportion of this is lying in an unavailable form and locked up as far as the plants are concerned. The addition of lime will frequently liberate plant foods that are tied up in the soil. FOURTEEN PLANT FOODS “As far as our New Zealand soils are concerned, although there are some 14 plant foods required, there is likely to be a deficiency of only three of these as far as we are likely to be concerned, and these are phosphates, potash and nitrogen. There is a very definite deficiency in our soils in regard to phosphate, ' while there are indications in Taranaki that potash is fast becoming the factor - limiting production in many cases, while there is also a . robability that nitrogen will need to be applied. As pointed out earlier, we open our farming account with a certain amount of phosphate, potash, nitrogen, etc., and the time will come when a depletion will occur with these unless the leakage of usage is made good each year. During past years we have been making good the usage of phosphate by applying super, slag, etc., while nature has helped us to keep our nitrogen supply up by the bacteria action of the leg.-

umes and in the nitrogen content of our rainfall, but little has yet been done to counteract the drain on potash, which, by the way, constitutes the main portion of the ash of milk. ■ “Dealing firstly then with phosphates, a plant food that we know to be lacking and holding down production, our principal fertilisers supplying phosphate are: Superphosphate, basic slag, Nauru, and the various other rock phosphates, and bone dust. While these supply phosphate they are not composed wholly of phosphate and some little difficulty is often experienced by the farmer in finding out just how to compare the phosphoric content of each. In England it is necessary to always give the phosphoric acid content of phosphatic fertilisers, but in this country it may be stated in different ways and this complicates matters as far as farmers are concerned. For comparison purposes all phosphates should be brought to a common term and for this purpose phosphoric acid content is usually used. To bring total phosphates to phosphoric acid divide by 2 1-5, thus a super having 44/46 per cent, total phosphate has 20/21 per cent, phosphoric acid, comparable with 20/22 per cent, phosphoric acid of high grade slag, and 35 per cent, phosphoric acid of a 77 tuicalcic rock phosphate. Another extremely important factor that must not be lost sight of, however, is the solubility of the phosphoric acid. While slag and super have the same quantity of phosphoric acid, the super is soluble in water, while the slag is not. Slag and rock phosphates, however, are soluble to a degree in soil water and this degree of solubility is termed ‘citric solubility.’ For instance, slag having 17.4 per cent, phosphoric acid has 15.9 per cent, citric soluble, or, in other words, 92 per vent, of it is citric soluble. A rock phosphate with 35 per cent, phosphoric acid has only 11.2 per cent, soluble or actually 32 per cent, of it is citric soluble, so that while you may have quoted to you a 17 per cent, slag and a 75 per cent, rock phosphate, actually in the slag there is 15.9 per cent, of phosphate available to the plant and only 11.2 per cent, of phosphate available in the rock phosphate. The degree of solubility will also determine the rate of activity of the manure, while in the case of rock phosphate the fineness of grinding will have some bearing on the rapidity of action. PHOSPHORIC MANURES “Dealing with the phosphoric manures individually superphosphate is manufactured in this country from imported rock phosphates (Nauru, North African, etc.), and sulphuric acid, this latter manufactured in this country also. As a local product, this manure is worthy of support, providing it will ‘deliver the goods.’ An average high grade super contains approximately 10.72 per cent, moisture, 1.76 per cent, silica, .84 per cent, iron oxide, 20.72 per cent, phosphoric acid, 24.71 per cent, sulphur and 28.38 per cent. lime. The lime and sulphur, however, are in a combined form called gypsum, which renders them unavailable to plants. Super forms the basis of. 1883 manure mixtures out of 2064 registered proprietary manure mixtures used in this country, including 65 brands of basic super, 58 of potassic super and 40 of ammoniated super. Economic conditions over recent years have been a large factor in the increased use of super and there is no doubt that there are many districts in this country where it gives the best results. “Basic slag is a manure that has been responsible for the building up of much of our grass land and' Taranaki owes much to this manure. Slag is all imported, the bulk of it being of Belgian origin. The slags of England are open hearth slags and are low grade, ranging round about 15 per cent, phosphoric acid. The Belgian slags, which are the by-products of the Bessemer system of steel manufacture, are higher grade, ranging from 17 per cent, to 22 per cent. An analysis of. basic slag discloses that it contains some 11 component parts, these being lime 45 per cent., magnesia 7 per cent., alumina 1.5 per cent., ferrous oxide 2 per cent., ferric oxide 15 per cent., with lesser amounts of silica and sulphur and 18 to 22 per cent, phosphoric acid. Generally speaking, slag promotes clovers very strongly, but that this is not always the case is indicated at the Stratford Demonstration Farm where, after 12 years’ slagging at the rate of 3cwt. per acre each year, the pasture showed 64 per cent, of perennial rye and 21 per cent, of white clover, quite a good balanced pasture. Just as economic conditions have encouraged the use of super, so they have sounded the death knell of slag to a large extent MANY ROCK PHOSPHATES “There are quite a number of rock phosphates on the market, under various trade names, but the principal sources of rock are Nauru Island, North Africa (Morocco and Tunis), Walpole Island and Seychelles. Some of these go under the name of Guano, but they are not true Guanos like the Peruvian Guano. Nauru Island rock phosphate has the highest analysis, having 36.5 per cent, of phosphoric acid, while the North African vary from 25 to 30 per cent, phosphoric acid. These manures, while not quite good in the long run, are slow in action, although some of the finest ground are medium acting. With regard to bonedust and similar animal manures, these are manures that we will probably hear more of in the future. While they do not give the immediate response of super or the rich green sward of slag, used in conjunction with either of these they will put a foundation in the land that will stand to the farmer. “Taranaki is a district where to-day we must consider potash almost in the same light as phosphate as far as grassland is concerned, and this is particularly so on land where production has been fairly high during past years. The chief potassic manures are sulphate of potash, muriate of potash, 30 per cent, potash and Kainit, and as with phosphates there has been some difficulty for the farmer in estimating the values of these manures from the potash content value. For instance, sulphate of potash is commonly called 90 per cent, potash, but it actually contains 48 to 50 per cent, of potash, while 30 per cent, potash actually contains 30 per cent, of potash. At present prices of £l9 15s a ton for sulphate potash and £9 15s a ton for 30 per cent., this latter is easily the best buying on a unit value basis, the price of a unit of potash as sulphate costing 8s 3d while a unit of 30 per cent, costs 6s 6d. Muriate of potash contains about 50 per cent, potash, but is seldom quoted in this country, while in England it is usually from £1 to 30s cheaper than sulphate. Kainit contains from 12 to 20 per cent, potash and at present prices the unit of potash in Kainit costs 8s even for the highest grade. One thing to be remembered, however, is that if potash is to be mixed with super oxother manures it may be necessary to use sulphate, as the lower grades are inclined to paste when left mixed for for long. If they are to be used straight away, however, they can be mixed all right. NITROGENOUS MANURES “With regard to nitrogenous manures these can be looked upon at the present time as special manures, only to be employed for special purposes, such as to 1 boost the hay or ensilage crop, to get a

bit of extra early grass, etc. The most common form in use at the present time is sulphate of ammonia, and this is used chiefly in conjunction with super as ammoniated super. Sulphate of ammonia is a manure that requires to be used with discretion, otherwise the slumping effect that may follow its use will far outweigh any advantage it may possess. It should only be used on good pastures and then only at a moderate rate and with increased phosphate. Other nitrogenous manures are nitrate of soda, calcium cyanonide, nitro-chalk and dried blood or blood and bone. This latter form is a cheap and safe form to use. Agricultural chemists are at present endeavouring to find a suitable form of nitrogen, and much more may be heard of this in the future. “With regard to manure mixing there are certain rules which should be followed, otherwise loss of fertilising units or injury to the mechanical condition may result. Super can be mixed with all manures except slag, and it can be mixed with slag if used immediately. Slag (or any manure containing lime) cannot be mixed with sulphate of ammonia.

“The last manure to deal with, the commonest, one of the most important, the cheapest, and yet the most neglected, is farmyard manure. Too often do we see huge accumulations of this valuable manure round the farm buildings wasting and causing trouble. One is often pointed out patches of luscious green herbage on the grazing fields and the remarks made are that ‘that’s how we would like the whole of our pasture land.’ Well, these patches are merely the result of stock nitrogen, and were the accumulations of manure round the shed to be distributed evenly over the pastures something akin to those green patches would be achieved. These remarks apply equally to the better harrowing of our grassland for the more even distribution of the animal droppings. To allow the droppings to remain undisturbed would be equivalent to a farmer obtaining, say, a ton of super or slag and putting double handfuls of this here and there over the pasture sward. If one saw this happening one would come to very definite conclusions about such a farmer and yet we allow that valuable animal nitrogen to lie in these small heaps.” BRAKE ON PRODUCTION POSITION IN SOUTH TARANAKI POSSIBLE CAUSES DISCUSSED The production increase of only 8 per cent, in South Taranaki this season, as indicated by the South Taranaki Herd Testing Association figures, is causing some concern among dairymen, who see in it the effect of low prices in restricting production. From a climatic point of view it has been the best season for many years. One South Taranaki grazier told the writer that it was the best season he had ever known for grass. He had never known sheep and cattle fatten so well, and the feed right through had been excellent. Other districts are showing much larger increases on soil that needs a good deal more top-dressing, which gives rise to speculation as to why the comparatively small growth in production this season. On the whole South Taranaki farms have been more heavily stocked than usual. One man with farming interests suggests that there may be a deterioration in the quality of the average herd. 'Hie bobby calf business affected the building up of herds while high prices lasted, and in addition the annual drpin from the Waikato has continued. Very few farmers have been able to hold on to their best calves when they have been sought by Waikato buyers. SHEEP BREEDERS TO MEET MASSEY COLLEGE GATHERING LECTURES AND DEMONSTRATIONS The large attendance of farmers from a very wide area at Massey College last year on the occasion of the annual meeting of sheepbreeders there was evidence of the appreciation of the previous meeting. From the interest taken in that meeting, as well as the fact that the sheep and its products is now attracting more attention, there is certain to be a much larger attendance at the annual meeting which takes place on Thursday and Friday, May 23 and 24. The programme arranged is a very comprehensive one, including lectures and demonstrations, and inspections of the Massey Agricultural College farm and of the grass and clover plots of the Plant Research Station. The programme of lectures and demonstrations include :“Types of Rape and Kale Used in New Zealand,” by Mr J. W. Hadfield, Department of Agriculture; “Research in Problems in Connection with the Treatment of Hidas and Pelts,” by Mr P. White, Department of Scientific and Industrial Research; “The Control of the White Butterfly,” by Mr J. Muggeridge, Plant Research Station; “Some Known Causes of Sterility,” by Professor G. S. Peren, Massey Agricultural College; “Foot Rot in Sheep,” by Mr J. M. McLinden, M.R.C.V.S., Massey Agricultural College; “Sheep Dogs,” by Mr A. C. Morton, Massey Agricultural College; “Chilled Beef; Type of Cattle Required and Process,” by □. meat trade expert (to be arranged); demonstrations on Romney sheep, by Mr J. E. Hewitt, Mangamaire, and Southdown sheep (demonstrator to be arranged). * * # * There are many farmers in New Zealand who will not agree that the dehorning of cattle is as painful—as distinct from cruel—as Lord Bledisloe would claim it to be. A well-known Taieri farmer states that the pain inflicted on an animal ■when its horns are cut off is similar to that experienced by a human being when he has a tooth extracted. There is a momentary acute pain and shock, and that is all. The Taieri farmer says that he has been dehorning cattle all his life and that within the past 18 months he lias treated over 100 animals. Immediately after the operation a dab of Stockholm tar is put on the wound. Not one death has to be recorded in the 1000 cattle dehorned, and the Taieri farmer states that in practically every instance the animals were feeding in the paddocks a couple of hours afterwards. He claims without hesitation that the temporary pain inflicted is justified in the result achieved, as cattle in herds, in railway trucks and in other confined spaces cannot wound each other as do cattle with their horns intact. A Dunedin man who has also had a wide experience of cattle states that he has seen an animal taken from a truck so badly injured by the horns of other animals that it died shortly after. He gave it as his clearcut opinion that dehorning may be painful, but that it is really a humane operation. Cows Going Off Quickly. Milk production is now falling off. “Despite the favourable weather conditions which have induced a good growth of grass it is impossible to keep up the milk supply,” remarked a coastal farmer. He considers that the cows are dropping their production this year more quickly than usual, and that it is probably accounted for by the fact that each year there is a tendency to bring the cows into profit earlier.