FERTILISERS

New Zealand Journal of Agriculture, Volume 71, Issue 3, 15 September 1945, Page 249

FERTILISERS

Making Most of Restricted Supplies

By

I. L. ELLIOTT,

Supervisor of Fertiliser Supplies;, W ellington.

WITH the start of the new fertiliser rationing year has come the realisation that even now the supply position is insufficiently good to warrant the : removal of the rationing regulations. The controls which are imposed as the result of wartime conditions are as distasteful to those who administer them as to those at the receiving end. There is, however, absolutely no doubt that a continuation of fertiliser rationing is' necessary to maintain equity of distribution.

READERS will remember that last year we were supposed to get more phosphate than the year before. We actually did get that phosphate, and consequently were able to announce a special ration based on lewt. per dairy cow, and various increases in the schedule of quantities for each acre of crops. This year the quantity of rock available for distribution has again been increased, and the provisions for the 1945-46 rationing year, already publicised, are briefly as follows: — 1. The elimination of - the special ration for topdressing dairy farms formerly available at the rate of lewt. per dairy cow. 2. An increase in the basic ration for topdressing purposes from 28 per cent, to 42 per cent. 3. The re-opening of the appeal procedure. There has been some criticism of these provisions, principally on account of the removal of the special ration for dairy farmers. The implications of this measure were fully realised by the National Council of Primary Production, but it was felt that in view of the demand from overseas for other than dairy products, it was impossible to justify continued preference in the matter of fertiliser supplies for the , dairy industry.

Now that the new rationing regulations have been announced, many farmers will be considering how to make the best of their allocation. Frequent reference has been made in the “Journal” to this matter, but it seems opportune to give a re-state-ment of the position. Helping Out Ration The first question one asks is what substitute materials can be used in place of fertiliser? Actually there are no completely suitable substitutes, but there are quite a few things which help. Probably the most important material available for use on dairy farms is the livestock excreta dropped round yards, which can be collected in tanks and distributed on the pastures from suitable portable containers. The whole of this question is fully dealt with by Mr. G. A. Blake in his article in the May, 1945, issue ; of the “Journal.” Although lime cannot in any way be viewed as a substitute for phosphate, it can be viewed as being a great help in the efficient use of phosphates. If a soil is deficient, in lime, there is every chance that the added phosphate, particularly if it is in the watersoluble form, will become “locked up” and unavailable to plants, i

When plenty of lime is present it enters into combination itself with the phosphate, and holds it in such a way that the plant can draw, on it when necessary. In this way, therefore, the use of lime will help to make the allowance of phosphate go further. It must not be overlooked, either, that lime is itself an important mineral in the growth of plants, pnder most conditions in New Zealand soils it is present .in sufficient quantity for purely plant food purposes, but there may .be certain conditions where lime is necessary from this viewpoint alone. Most plants grow best under certain conditions of soil acidity, and are frequently only tolerant to changes within a narrow limit. For general purposes it is desirable that soils be on the slightly acid side of neutrality. The fact that plants react to changes in soil acidity is clearly shown where applications of sulphate of ammonia have been made to golf greens over many years. In this instance the clovers and demanders of less-acid conditions have disappeared, to be replaced by a browntop-dominant soil covering. If the process is reversed and lime applied to a sour acid soil supporting only browntop, clovers and other grasses will begin to appear as the soil approaches neutrality. By assisting in , keeping general soil conditions right, the use of lime helps to conserve the use of phosphates. Much attention has been focused of late on compost, and many recommendations made about its preparation. Composters have at least performed the very useful service to the community of focusing attention on the importance of humus in the soil.

Where arable cropping is practised ■or where the inter-cultivation of fruit trees has to be performed much can be achieved to conserve supplies of fertilisers by growing green crops :such as cape barley, oats, or lupins, ■and ploughing these in. In many cases it is better practice to feed off the green crop in situ, when the material is ultimately returned to the

soil through the excreta of the grazing animal. Making Best of It Having covered most of the means at the disposal of farmers of using materials which to some extent can be considered complementary to fertilisers, some consideration can now be given to the use of the _ actual

quota made available. It seems that the problem has been substantially answered when the farmer is told, ‘Tut on the right kind of fertiliser in the right way, at the right time, and in the right place.” A statement of this type is, of course, very indefinite, and requires modification, but the modifications required are those imposed by the conditions under which the farmer himself works and of which he should be a capable judge.

Using the right kind of fertiliser will help in using fertiliser to the best advantage, because the right kind of fertiliser to use is obviously the most efficient one under the particular circumstances concerned. The common answer to the enquiry, “What kind of fertiliser shall I topdress my paddocks with?” has been, “Superphosphate.” Departmental trials carried ou.t for some years have tended to show that superphosphate is not always the answer to the farmer’s prayer, and that in a very large number of cases serpentine superphosphate more closely approaches the ideal. In still other cases basic slag gives better results than straight superphosphate and in still others lime-reverted superphosphate comes out on top. In some localities and for some purposes, it is not even advisable to stick to a purely phosphatic fertiliser, and potash and perhaps nitrogen should be used as well. Although the answers to all the questions about fertilisers and their use are not yet known, the most reliable

source of information in all these matters will be the local Instructor in Agriculture.

Applying Fertiliser The ways in which fertiliser can be

applied to the soil are not very diverse, and for topdressing purposes the fertiliser cannot be incorporated in the soil, and must therefore be simply distributed as evenly as possible over the surface. When it comes to using fertilisers for cropping purposes or for the establishment of new grass there are several interesting possibilities for achieving better plant food uptake.

In certain parts of America it was found that the wheat crop suffered from nitrogen starvation during long dry spells, so the theory was developed that if the fertiliser was “put down” it would be away from the dry surface layers of the soil and would be in a position where the plant roots could use it. This theory was found to be sound, and much overseas literature is giving prominence to the value of putting fertiliser down. For best results special attachments were used on the plough and the fertiliser was applied in a band on the plough sole. Here in New Zealand these special attachments do not seem to be available, and the nearest approach to the method can be achieved by broadcasting the fertiliser and ploughing it in. That such methods are of application here under some circumstances, at least, has been demonstrated by Jacques at Massey ■College and by later work at Massey College and by the Fields Division of the Department of Agriculture. Although this method commends itself as being well worth a trial, particularly in the drier areas of New Zealand, further experimental work is necessary, and will no doubt engage the attention of the new Fertiliser Research Station at Hamilton in the near future.

In order to give the plant a rapid and vigorous growth in the early stages of its development, certain “starter” dressings were given. These were applied as close as possible to the seed, but not so close or in such a way as would damage the seed or the root hairs after the seed had germinated.

Under conditions where intercultivation is normally carried out dressings in bands can be made alongside the rows of plants or alongside the seed at the time of sowing. Placing fertiliser in this way ensures its efficient use and its minimum loss in the soil.

Time of Application

There has been and is likely to be for some time to come considerable difficulty in making deliveries of fertilisers to farmers at the time when

they would do most good, and to this extent the time of application has in most cases been outside the control of the individual farmer. In those cases where storage space is available supplies can be taken in and held until such time as they are required. If this is done, only a fertiliser which can suitably be stored should be accepted. Assuming, however, that the fertiliser is available to be used when required, it should under most North Island conditions be applied in the autumn, say in March or April. If it is applied too late, there is little doubt that much of its efficiency will be lost. Under South Island conditions spring applications can be made with excellent results and in such a way that they do not conflict with the other urgent operations which take place on many farms in the autumn. Here again there is room for variation, and in the warmer parts of the South Island where North Island conditions are approximated autumn applications are better. In the far south spring applications are to be favoured, on account of the more lengthy and severe winters.

Where to Topdress

A further point of importance in the application of the fertiliser on any individual farm is which particular paddocks or part of the farm to topdress. This is essentially a question about which the farmer must make up his own mind, although one or two general principles should be borne in mind. First, it is not much use under present conditions of fertiliser shortage to try to bring back run-out pastures with inadequate supplies. It will generally be more payable to look after the better pastures on the farm and to prevent them as far as possible from deteriorating. A sufficiency of clover in the pasture is

absolutely necessary to get a good phosphate response, and to this end adequate dressings with lime will help the clover position.

Having now had some years of fertiliser rationing, many farmers will no doubt be asking themselves whether they can maintain their pastures as well with lcwt. of superphosphate as they did pre-war with three. In some cases the answer will perhaps be yes. If the answer is positive over a considerable area, there seems little doubt that large quantities of fertiliser have in the past been wasted. That such is in fact the case is hinted at in some contemporary work. In the meantime, however, observations such as this should be treated with considerable reserve, although they open up interesting avenues for speculation.

PASTURE PRODUCTION IN N.Z.

An outstanding summary of the appearance and uses of the grasses and clovers in the Dominion is given by S. H. Saxby in Bulletin No. 250, “Pasture Production in New Zealand.” He discusses the different types of grassland — country, short rotation, permanent pasture, —with ' the management and seed mixture required for each. The topdressing, harrowing, and topping of pastures, the making of hay and silage, the establishment of new pasture and many other important practical aspects of grassland management are dealt with in a clear and helpful manner. Every farmer concerned with getting the maximum from his pasture should obtain this booklet.

Obtainable from the Department of Agriculture, Auckland, Wellington, Christchurch, and Dunedin. Price 1/-.