LIME AND LIMING IN THE SOUTH.

New Zealand Journal of Agriculture, Volume XIII, Issue 2, 21 August 1916, Page 87

LIME AND LIMING IN THE SOUTH.

Paper read by Mr. W. D. Hunt, Representative of the Southland Agricultural and Pastoral Society, at the Annual Conference of the New Zealand Council of Agriculture, held at Wellington, July, 1916.

Z H|" A HE district of Southland and the adjoining districts of south I Otago have been the pioneers in the use of lime in connection with the agriculture of New Zealand. The first to use lime

on an extensive scale in this country was the New Zealand and Australian Land Company, on its Edendale Estate in Southland. The company made a beginning in 1890, during which year it limed about 200 acres. It continued the work until it disposed of the property in 1904, partly by sale and subdivision to settlers, and partly by sale to the Government for closer settlement. During these fourteen years the company limed about 6,000 or 7,000 acres with an average of about 2 tons of burnt lime per acre. The use of lime on an extensive scale has been continued since 1904 by the settlers, and the Edendale and surrounding districts are

now by far and away the best example of successful liming to be found in the Dominion.

The credit for initiating and continuing this work belongs to the late Mr. Thomas Brydone, then superintendent in New Zealand for the Land Company, and Mr. Donald Macdonald, who managed the Edendale Estate during the whole period that the company was using lime upon it. Both these gentlemen had had previous experience in the use of lime in Britain before coming to this country. When the estate was subdivided Mr. Macdonald bought the Edendale homestead and about 1,700 acres of land attached to it, and he still lives there. He has had more experience in the use of lime than any one else in the Dominion, and is as enthusiastic about its use as ever.

The following figures will give an idea of the manner in which the use of lime has increased in Southland and south Otago. The year 1890 can be taken as the date when the commencement was made in a practical way. Ten years laterthat is, in 1900 — output. of lime from the works in the districts named had grown to approximately 11,000 tons for the year. In 1905 the output was 17,000 tons ; in 1910 it was 20,000 tons ; and last year, 1915, the limeworks of Southland ,and south Otago put out 37,000 tons.

The use of lime in agriculture is no new discovery. Its use goes back probably thousands of years. It is too large a subject to deal with comprehensively within the limits of a paper such as this. I shall not attempt to treat the chemical or scientific side of the subject. Any one wishing to study this side of the question can find many books and pamphlets on the subject that deal with it much better than I can. I will confine my remarks chiefly to the experience gained in the use of lime in Southland and south Otago, and, unless otherwise stated, anything I say refers to the use of lime in those districts named, and not elsewhere.

Lime is used in three forms —(i) Shell burnt lime, (2) ground burnt lime, and (3) ground carbonate of lime, or raw lime.

SHELL BURNT LIME.

This was the first method used, and although the others mentioned have been used largely, and at a steadily increasing rate during recent years, there is still probably more shell lime' used than either of the other forms, although ground burnt lime will now run it pretty close. All the liming done by'the Land Company was with shell lime ; in fact, the other two forms have only come into extensive use since the subdivision of the Edendale Estate. Shell lime, as you probably all know, is the burnt lime as it comes

from the kilns. It is in lumps averaging about the size of a teacup. The present cost of this lime is 15s. per ton in bulk ,on trucks, in truck-load lots. The railways carry lime free of cost for distances not exceeding 100 miles, and as every railway-station in Southland and south Otago has a lime-kiln within 100 miles, it means that farmers can buy shell lime at 15s. per ton at their nearest station.

The lime must be carried straight from the trucks to the paddock in which it is to be used. It is applied to the land after the latter is ploughed, generally at the rate of 2 tons per acre. The best method of doing this is to mark the paddock off in lines 8 yards apart. The lines are poled off just as one would do in laying off a paddock for ploughing in lands. A horse drawing a light plough, a log of wood, or anything that will make a good clear mark is driven along the lines. The man carting the lime then takes his dray along these lines, and every 8 yards stops and puts out three shovelfuls. of the shell lime in a heap. The shovels used are the short-handled, square-nosed shovels commonly known in the South as lime-shovels. When the carting is finished the paddock will be dotted with heaps of lime 8 yards apart every way. Heaps this distance apart each containing three shovelfuls will equal approximately 2 tons per acre. The lime is then left until it has air-slacked. In this process it increases enormously in bulk and forms into a fine powder. Directly it is in this state it should be spread. The spreading is done with a shovel, and with a little practice and care a man can spread it in this way very evenly over the paddock. If it is desired to use' less than 2 tons per acre, as little as 1 ton of shell lime can be used. When using this quantity about a shovel and a half is put in each heap, and then, in order to increase the bulk, three or four shovelfuls of earth should be thrown on each heap. In slacking, the lime will rise, right through the soil, and the two~ will be thoroughly mixed together, and' then can be spread. Unless the bulk is increased in this way as small a quantity as 1 ton per acre cannot be spread evenly with a shovel. Even though mixed with soil as stated,' a smaller quantity of shell lime cannot be spread evenly. After being spread, the lime should be well worked into the soil by cultivation. . '

GROUND BURNT LIME. ' This is merely the shell lime put into a grinder and ground to a coarse powder. It is put up in sacks, and is railed in truck lots free in the same way as shell lime. It is sold at £1 per ton the sacks are charged for, and, if returned, are allowed for, generally

at about 2d. each less than the cost price. Including the sacks, therefore, the cost comes to, roughly, £1 2s. per ton. Lime-spreaders are used to spread this lime, and it slacks on the ground. Several useful horse-drawn machines are on the market for this purpose; they can be set to spread from a few hundredweight to about 2 tons per acre ; their cost runs to £2O to £25 per machine. Care must be taken to spread ground burnt lime as soon as received, otherwise it will air-slack and burst the bags. Ground burnt lime came on the market at a much later date than shell lime, but its use has '■ increased very much during recent years. It costs more than the shell lime, but it is more convenient to spread, and it can be used in much smaller quantities.

GROUND CARBONATE OF LIME, OR RAW LIME.

This has only come into use comparatively recently. The raw limestone is taken just as it comes from the quarry. It is first broken into small pieces in a jaw crusher or other suitable machine, then dried by artificial, means and ground to a fine state of division. The fineness of the grinding is important if ■ quick results are to be obtained. Drying is necessary to enable it to be ground finely, as moist stone cannot be ground efficiently. Ground carbonate of lime is put up in sacks and sown through a lime-spreader in the same way as the ground burnt lime. It is often used, too, in smaller quantities by mixing it with . manure and sowing it through the ordinary seed and manure drills. The price - charged for carbonate of lime has varied from 16s. to £1 per ton, according to. the fineness of the grinding. Bags are charged as extra as with burnt lime, and railage for 100 miles is free. Carbonate of lime came on the market later than burnt lime, and the total quantity of it used is very much below that of either of the two classes of burnt lime. . The use of carbonate, however, has been steadily on the increase during the last few years.

RELATIVE VALUES OF BURNT AND CARBONATE OF LIME

There has been considerable controversy on this . question. Carbonate of lime when burnt in a kiln becomes quicklime. In the process of burning it loses 44 per cent, of its weight. When air-slacked and mixed with the soil it changes into carbonate of lime again and regains its former weight. In the ultimate result both are carbonate of lime, and looked at in this way 56 lb. of burnt lime should be the equivalent of 100 lb. of finely ground carbonate. Some years ago a series of experiments were conducted .in the United States of America with the two classes of

lime, and in these experiments the lime was used approximately at the equivalents I have named. In every case and from every point of view the carbonate of lime gave the best result. The bulk of our experience in the South bears out these experiments, and it is evident that for some reasons the equivalent in practice is much nearer than 56 .to 100. Besides this, the carbonate of lime is much more convenient to use. It can, . too, be sown in smaller quantities in drills mixed with manure and be put right alongside the seed. Burnt lime cannot be used in this way. For the reasons stated many people prefer carbonate of lime to burnt lime, even when the costs are equal.

PRICES.

I have stated the price at which the different kinds of lime are being sold in the South. I do not see any prospect of a reduction in the price of burnt lime. The steady rise in the cost of labour is not only increasing the cost of handling the stone, but it is also increasing the cost of the coal necessary to burn it. Railway rates, too, have lately been raised, and this further increases the cost of the coal. I think the tendency is more in the direction of an increase than a decrease in the cost of burnt lime.

Carbonate of lime has not yet been going long enough to say just where the selling-price will settle. The output is, as yet, not very large, and the machinery for dealing with it, under the conditions existing in this country, has not gone very far beyond the experimental stage. The chief difficulty to get over is that of drying. The limestone must be thoroughly dried before it can be ground to a fine state of division. The slightest dampness in the stone will decrease the output and spoil the grinding immediately. In some parts of the United States, I understand, carbonate of lime is sold in bulk on trucks as low as 3s. per ton, but there the conditions are entirely different. The climate where, these works are situated is dry, and the limestone can be crushed without any artificial drying. Then, the output is enormous, and the most up-to-date labour-saving appliances can be used. I understand, too, .that the production of carbonate, of lime is largely a by-product of these works. The main object of the works is either the burning of lime for building purposes, which after burning is casked up and sent all over the United States, or the crushing of lime for use in connection with steel and iron works, and for road and ballast purposes. With all these processes a large quantity of fine material is obtained in the crushing of the rock. This material would in any case have

to be moved out of the way, and doing so would cost money. It can therefore be disposed of at a very low rate. Such conditions do not apply in this country. New Zealand, although a comparatively small country, is sb formed that no one spot can command more than a small proportion of it, and the result is that no one limeworks can command a big enough area 'to get the large output required to enable the most up-to-date laboursaving appliances to be used. Some of the , American works crush more lime in a week than the best-situated works in New Zealand are likely to put out in a year.

The ground carbonate of lime in this country is never likely to be a - product from works whose main output is either burnt lime or crushed rock required for the purposes I have mentioned. The crushing of carbonate of lime for use in agriculture will in this country 'be the main object of . any works erected, and it is to the carbonate of lime and not to any of the other products mentioned - that the works must look for expenses and profit. In the South the climate is fairly wet, and the limestone comes out of the quarries in a wet state and takes a lot of drying. The greatest demand for lime is 'in the winter and spring months, whereas the time of the year when the limestone is driest is the summer and autumn months. Grinding in these months would be cheaper than in the winter and spring, but the storage of the ground material involves extra handling, which would more than do away with any saving. , If limestone, after being quarried, is left out in the open for a month or two before grinding it dries to a considerable extent, but not enough to do away with artificial drying altogether. This, moreover, involves a second handling, which more than balances the' saving in drying. Our southern limestones when taken from the quarry in • winter contain from 15 to - 20 per cent, of moisture. To grind efficiently the moisture must be reduced to a proportion not exceeding 3 per cent. This makes it necessary to . take about 15 per cent, of moisture out of the stone, which means the removal of - about 3 cwt. of water from every ton of rock.

In north Otago and Canterbury climatic conditions are much drier • than in Southland and south Otago, and limestone could be ground much cheaper there than with us. The same may apply to a comparatively dry climate like that of Hawke's Bay, but I think it is the wetter parts of New Zealand that are going to require ‘ lime most. The lime will have to be ground somewhere near the districts where it will be used. Free railage only extends to zoo miles, and if it is carried - farther than this and railage has to be paid the saving in the cost of drying in the drier area is lost. If the demand for carbonate of lime increases

so that works can get a . larger output and the machinery and facilities for handling it are improved, I think it probable that prices could be reduced, somewhat from those now , being charged.

The outlook for prices generally is that those for burnt lime will not be reduced, - and may .be increased, while those for carbonate of lime will probably be reduced.

QUALITY OF LIMESTONE-DEPOSITS.

From my experience, it is never safe to judge the quality of deposits by merely taking a few samples out of the face. The actual quality of the body of the rock can never be definitely ascertained until after it has been opened up to a certain extent. I have noticed great difference in the quality of layers in the same quarry. The different layers run horizontally, or at all events originally ran horizontally, but may have dipped in one direction or ' another through movements of the ’ earth's crust. A layer of first-class stone is sometimes found overlying a layer of inferior quality, and then a first-class layer underneath again. The best way to judge a deposit of limestone before it is opened up is to have bores put down in different places to the depth that the limestone-deposit will probably be worked, and have samples analysed from different levels in the bore. By this means, before the actual work of quarrying begins, a fairly accurate knowledge can be obtained of the class of stone to be met with.

APPLICATION OF LIME.

In the South we generally find that our land wants a dressing of about 2 tons of lime per acre to start with. After that a smaller dressing can' be used every few years, but the first dressing requires to be a good one. If 2 tons cannot be put on, smaller quantities are better than none. Even a few hundredweights can give good results. Before liming, the land must be thoroughly drained. It is no use liming land that is not well drained; putting lime on wet land is mere waste of money. The lime, too, must be put on the surface ; it always has a tendency to sink. If it is ploughed in to any depth, little good is obtained from it. The best way is to put it on before sowing down in grass, and the longer it can be put on before the. grass is sown the better. The best way of all is with a crop of drilled turnips, if this is to be followed by sowing the land with grass. The lime is put on the surface after the land is ploughed for the turnips, and is thoroughly worked in, first by cultivating the land, then by the raised drills for the turnips, and finally by the cultivation and thinning that the turnips receive. After the turnip crop is eaten off. the land should be ploughed as

lightly as the plough can be got to run; not more than 3 in. deep at the outside, and less if possible. This is merely turning over the top 3 in. of soil that the lime has been thoroughly mixed through by the cultivation in connection with the turnip crop. If the land is then sown with grass the result is immediate, and the grass comes away very much more quickly than if the land is only limed before sowing the grass.

EFFECTS OF LIMING.

The effect of lime on our South grass-lands, where they have been thoroughly drained, is nothing short of marvellous. It seems to completely alter the nature of the soil. The growth of all the best grasses, and particularly clovers, is promoted to an enormous extent, and the lime either has the effect of directly checking the weeds, couch, and other valueless grasses, or else the effect is indirect through the growth of valuable clovers and grasses being so stimulated that they smother and destroy the more worthless plants. While grain and root crops are greatly benefited by the use of lime before sowing, the greatest benefit is derived by grass, and by the grain and root crops that are grown after the limedressed land is broken up again. How long the effect of a dressing of 2 . tons to the acre will last I cannot say, but I . know that land that has been limed and left down to grass for twenty years has been enormously benefited by it. No land seems to give such good and quick returns from root, grain, or green crops as an old grass-paddock that has been limed previously- when it was sown down in grass. Possibly much of the lime itself may have been lost,. but the increased growth of grass particularly clovers brought about by the application of lime seems to fill the' ground with humus, enormously increases its fertility, and thoroughly changes its nature. Lime. not only increases the quantity of the grass and clover and subsequent grain and root crops, but it seems to have a great effect on the quality. Stock fattens and . thrives very much better and faster on limed land than on land that is unlimed, and the carrying-capacity is largely increased.

LIME AND ARTIFICIAL MANURES.

Lime seems to be of great ' assistance to artificial manures. Crops and grass 1 respond much better to artificial manures on limed land than on unlimed. The farmers in the South who are the largest users of artificial manures are those who have limed. Nitrogenous manures are not so much wanted on limed land. The growth of clover is largely promoted by lime. Clover collects

nitrogen from the air, and this seems all that is required. Phosphatic manures., on the other hand, give marvellous results on limed land. Many of our South lands would . not grow clovers at all until they were limed. As one farmer put it to me, “ I never sowed clovers before I limed, because they would not grow; now I never sow them, because they seem to be naturally in the land and come up of - their own accord.”

The first expenditure in our South lands should be for draining ; nothing else is any good until that is attended to. The next expenditure after draining should be for lime, and after lime phosphatic manures can be supplied; but the longer the land can be left in grass after the land has been limed the better, for it is the growth of grass brought about by the lime and humus-content that seems to be the chief cause of the fertility of the land that is limed. I knew a farmer who when sowing a paddock out in grass put 2 tons, of lime per acre on half the paddock and an. equal money value of phosphatic manure on the other half. There was no comparison between the two sides; the limed half completely beat the manured half. A few years ago I saw a paddock ploughed up and sown in an oat crop without any manure. The paddock had been down in grass for ten years when the crop was sown. Half the paddock had been limed with 2 tons per acre when the grass was sown ten years previously, and the other half had received no lime. The oat crop on the half that had been limed was more than .twice as heavy as that on the unlimed, portion. ■ The dividing line could be seen straight across the paddock, and there was a difference of quite 15 in. in the height of the two. portions ■ of the • oats.

Last year . I saw a paddock sown in swede turnips. It was ploughed out of land that had been sown in grass for seven years. When sown down with grass half had been limed with about 30 cwt. of lime per acre; the other half had had no lime. The turnip-drills were sown across both limed and unlimed portions, so that each drill was half on the land that had been limed and half on the land that had not been limed. The turnips on the limed portion had to be thinned quite three weeks before the turnips on the unlimed portion. The crop on the limed portion was a splendid one, ' and a very indifferent one on the unlimed portion.

TOP-DRESSING PASTURES.

Lime can be used very effectively in top-dressing grass-lands after they have been sown down, and if in addition to the lime a top-dressing of phosphatic manure is supplied the result is simply

marvellous, and the best of permanent pastures can be obtained on' land that previously would not hold grass for a few years. In speaking of these results, it must be understood that the land has first been effectively drained and the suitable grasses are growing in the soil. Top-dressing in the manner stated will enormously stimulate the growth of grasses and clover, but will not create them. In . top-dressing with phosphatic manures the lime should always come first, and if the available funds are limited they should all be spent on lime till 2 tons per acre are supplied. If further improvement is wanted, then apply the phosphatic manure.

CONCLUSION.

I said at the outset that I was speaking of conditions as I have found them in Southland and south Otago. Whether these conditions apply to other parts of New Zealand can best be found out by farmers experimenting for themselves. Mr. William Perry, of Penrose, Masterton, tells me that he has now limed about 500 acres with satisfactory, results/ but he is here to-day, and will, I have no doubt, give you his experience if you. ask him. Were I farming in any part of New Zealand I should certainly try lime. I was once travelling through one of the most fertile districts in the North Island the season was good, and the country looked lovely, and I expressed my admiration to the local resident who was showing me round. “Yes,” he replied, “it is a splendid .country. The Lord does the work for us here. All. you have to do is not to interfere with Him.” This statement may be true .of some parts of the Dominion, but I know in the South the Lord only helps those who help themselves, and He gives ■ help in double measure to those who lime. From my experience I would try to tempt Him with lime, no matter what part of New Zealand I was farming in.