TOP-DRESSING.

Waikato Times, Volume 111, Issue 18625, 3 May 1932, Page 12

TOP-DRESSING.

A UNIVERSAL NECESSITY. MARKED FALLING OFF IN PRACTICE NEEDS OF GRASSLAND. Farm Incomes at the present time are so seriously reduced as to make it absolutely necessary for all expenditure to be kept as low as possible, but notwithstanding this, a topdressing programme greater than has ever before been carried out is a general necessity on every farm during the coming few months. The financial position is admittedly serious. In certain instances great and possibly permanent harm would follow unwarranted and injudicious expenditure. While there is call for expenditure that will give assured satisfactory returns, no other type of expenditure should be embarked upon. While realising all this, one is driven by the force of the available evidence to advocate an increase rather than a decrease in the farmer’s expenditure on top-dressing. The available evidence, indeed, goes farther than has as yet been indicated herein. It may be said not only that top-dressing may be employed to make the position on farms better, but also that if it is not so employed the position on many farms will become appreciably worse. In every extensive farming community occurs a section whicli in the past carried on in a manner satisfactory to itself without resorting to -topdressing. In the changed present times that section generally will still exist, but as a rule it has become smaller. Probably many of the members of that section would have been better off in the past had they top-dressed. Now It may be necessary for. them to top-dress, not as a means of primarily improving their old position, but as a means of conserving their -continuance as farmers. This is as aspect of top-dressing which many who have not practised topdressing in the past or who have carried it out only on a restricted scale or in a spasmodic manner, should carefully consider. Some who have farmed profitably with little or no top-dressing in the past may attribute this mainly to the fact that they were working under exceptionally favourable circumstances such as lefw original cost of land. Their profits often would have been greater from the assistance of top-dressing, and now if they are to have any profits at all it may be necessary for them to topdress. To many farmers some of the basic facts just stated may seem to be truths so self-evident as to make it unnecessary and pointless to express them. Unfortunately, they are not self-evident. The best evidence of this lies in the general agreement among those who have had good opportunities of gaining reliable information, that the top limits of profitable top-dressing have not as yet been approached in this Dominion. This agreement was made very dear just a Year ago at a gathering of representatives of the main grass-farming .advisory and research organisation when the value of top-dressing as a means of lowering cost of production was stressed in a statement that won unanimous support. Falling-off In Top-dressing. Further evidence obtained in the intervening 12 months has served merely to strengthen the view then accepted. While those of wide knowledge and experience insist that the present need is for more instead of for less top-dressing, we have farmers at times saying that they intend to reduce or eliminate their top-dressing in the belief that they ‘‘-cannot afford to topdress." When pressed for the reasons forming the basis of their belief, such farmers as a rule are at a loss, and resorfc, to vague generalities and impressions to support their most pernicious doctrine, which in general is the very reverse of the actual position. That these men act upon their belief is indicated to some extent by tho railway deliveries- of fertiliser, which for nine months of the current year ended in March are from -10,000 to 50,000 tons less than for the corresponding period in the previous year. Whichever way it is viewed, this decline is most regrettable. It is probably due partly to farmers who could finance top-dres-sing being content to dispense with its assistance. Their ignorance of what is sound practice is surely most regrettable. It is probably due partly also to farmers being unable to finance top-dressing .which they know directly and definitely benefits them. Their financial plight is surely most regrettable. Fortunately, hard as the times are, these latter farmers arc likely to be in the minority, far as a rule'the interests financing farmers, rightly, will give credit for the purchase of top-dressing material when they would not give it for many other purposes. Unprofitable Top-dressing. The preceding statements are subject to two qualifications. First, there are grassland areas for which top-dressing is not recommended. These, however, are exceptional, and any farmer should make -sure his is one of the exceptional -cases before he decides to carry on without the substantial assistance usually available from top-dressing. Secondly, the financial benefits to which reference has been made presuppose judicious expenditure on topdressing. If top-dressing is not carried out wisely and linked up soundly with other aspects of pasture management it may result not only in disappointing returns, but also at times in positive harm to pastures. “What, then,” the practical man will ask, “is judicious top-dressing?" Fortunately, in New Zealand the main requirements of the top-dressing posilion are not so hidden as they seem {o be in some other countries. Importanoo of Phosphates. In general, the supply of available phosphate is tho weakest link in the ■chain of crop requirements. Until I his chain is strengthened in its weakest link production is unduly depressed. The deficiency of phosphates, though not universal, is very general In New Zealand soils. Hence, as a rule, the primary consideration in New Zealand top-dressing is tho supply of phosphates. Unlit this lias been placed in a satisfactory position, it is seldom advisable to supply other top-dressing material. An occasional exeeplion lo this rule arises in respect In lime for sometimes phosphalic fertilisers will not function satisfactorily unless linked with liming. But as a general rule I lie first consideration should ho phosphates. Of the phosphalic manures, superphosphalc is most largely used. Field experience quite justifies this. Superphosphate as a rule excels all other

phosphatio manures in localities of low rainfall, and In districts of high rainfall it will generally hold its own at least with oilier phosphatio manures. It makes its inlluence felt more quickly than other material. It is not nearly so temporary in its beneficial effect as some profess to believe. This may be gathered from the fact that in carefully observed instances, superphosphate has been functioning quite appreciably at 12 months and more after its application. Despite past teaching to the contrary, it is now definitely established that superphosphate does not cause any permanent sourness of the soil. To sum up, it may be said that super may be used over wide areas with great satisfaction —quick return, high response, •and reasonably long effect. Next In importance to super and of considerable moment Is basic slag. In the past cn many farms splendid results have been obtained from the use of slag. In such cases it would be unwise to depart from the use of ■slag, except on an experimental scale,, until evidence has been obtained .ol superior returns from the top-dressing material with wh.ch it is intended to replace the slag. In districts of good rainfall, African and similar phosphates may be expected to give good results, but because of the -comparative slowness of their action should not be used alone when an early response from tho topdressing Is desired. Over wide areas a mixture of equal weights of one of these phosphates and of 44 per cent superphosphate is likely to producegood results on pastures. Potasslo Top-dressing. In certain districts, as, for example, in parts of Southland and In parts. of Taranaki, official trials have given indication of definite responses upon the use of potash in grassland. In districts in which such responses are being obtained farmers are justified in making fairly extensive trial use of potash. The use of potash should be linked with the use of phosphates, for the evidence points to a double deficiency in the soils of the districts -concerned, and if this double deficiency is not remedied the use of potash alone Is unsatisfactory. Apart from the particular districts in which responses to potash have been noted In official trials there is- no evidence to justify recommending the use of potash in top-dressing generally. Nitrogenous Manures. In dairying autumn top-dressing with nitrogenous manures calls for. a word of mention. In those cases in which a shortage of winter feed is in prospect the use of soluble nitrogenous manure, such as -sulphate of ammonia or nitrate of soda, in April, at the rate of about lewt an acre, may be a useful emergency measure to increase the winter feed supply. The use of such nitrogenous manures is satisfactory as a rule only in conjunction with the use of phosphates, which should be applied -shortly prior to or at the same time as the nitrogenous topdressing. Response to Lime. The matter of the liming of pastures is one about which advice is freely given without any evidence lo support That advice. The orthodox view of former times that liming is practically always sound cannot now he accepted. In New Zealand liming of grassland has produced very diverse results. Sometimes liming is obviously advisable; at other times it gives no apparent result. In view of this, -expenditure on liming should not be. incurred without careful -consideration. Liming by itself is seldom financially attractive' It is, as a rule, unwise to resort to lime as a -substitute for those more -costly artificial ferilisers, such as superphosphate and basic slag, the worth of which has already been proved. (However, If these latter manures are not giving satisfactory results, the use of lime in conjunction with them is well worth a trial. The point probably of major -current importance is that liming, as -a cheap alternative to other top-dressing of proved value, is, as a rule, false economy which Is likely to beget disastrous results. Position Summarised. In conclusion, the present grassland position may be summed up in the following facts;— Despite the urgent need of keeping down farm expenditure generally, the free use of suitable fertilisers on grassland is to be strongly recommended. Further, while judicious top-dres-sing may mean the salvation of some farmers, other farmers, by not topdressing, may go from bad to worse financially. Extensive evidence shows that the current’ need is for a greater use of fertiliser on grassland than at any -time in the past. Phosphates are of general and of basic importance. First attention should usually be given to the phosphatic requirements of pastures. Potash and nitrogen at -times prove useful auxiliaries to phosphates. If care Is not exercised in tho use of lime, money may be spent comparatively ineffectively. Liming as a cheap substitute for other lop-dressing is as a rule false and dangerous economy.