SEASONAL NOTES.

New Zealand Journal of Agriculture, Volume 54, Issue 6, 21 June 1937, Page 368

SEASONAL NOTES.

THE FARM. The Problem of Inferior Composition of Pastures. There is evidence in the main grass-farming districts of a tendency on the part of both dairy-farmers and sheep-farmers to continue using swards composed of inferior plants when it would be relatively easy and distinctly profitable to replace them with swards consisting largely of more productive pasture-plants. . This is particularly true of the many farms on which it is customary to experience shortage of feed at one or both of the critical seasons of low direct production of pastures the late-winter and early spring period and the late-summer period. There are three basic facts in this matter. . In the first place there are inferior pastures of which economic improvement is or at least is considered to be impossible in the light of our present knowledge. Secondly, such pastures are not at all as numerous as many seem to believe, and additions to our experience are periodically making them less' numerous ; for instance, the use of subterranean clover makes it possible to improve remarkably certain poor pastures, whereas payable means of improving these pastures without using subterranean clover are not known. Thirdly,, after making full allowance for the dwindling number of pastures which we do not know how to improve economically we have thousands of pastures which can be improved profitably by one or more of the following practices : top-dressing, surface-sowing of seed, and resowing on a cultivated seed-bed. While poor pastures can often be improved substantially by suitable top-dressing, it should be borne in mind not only that the repairing of pastures by top-dressing alone is usually a relatively slow process, but also that the amount of improvement possible under normal management depends to a large extent upon the plants which are present at the outset, and, because of this, at times it is not as great as is desirable. In certain circumstances which are not at all uncommon the surfacesowing of suitable seed in combination with appropriate top-dressing gives much greater and quicker improvement than could be obtained by topdressing alone. Surface-sowing of two distinct types has on occasions been carried out successfully on poor pastures. Firstly, there has been the use of a mixture designed to give a good mixed permanent pasture ; of this the total experience is not extensive, and, further, failures from such surfacesowing must be viewed as a possibility. Secondly, especially in recent years, surface-sowing has often been confined exclusively to the use of subterranean clover, and this in quite a satisfactory percentage of cases has been attended with distinct success when the pastures have been so open at the time of surface-sowing that the seedlings of subterranean have been able to establish themselves without the competition for a foothold in the soil and for a supply of sunlight which they have to face in dense swards, say, of brown-top, for instance, on which surface-sowing has been far from uniformly successful. By the foregoing statements it is intended to indicate that top-dressing, or top-dressing in combination with surface-sowing, at best is a somewhat uncertain or imperfect means of improving poor pastures. Hence, frequently the case for the renewal instead of the repairing of poor pastures is a strong one. The repairing process, however, may be the best course when the farmer is handicapped in regard to finance or labour or when all the equipment to be used in the work of repairing would have to be purchased. Again, the repair of pastures may be the only possible course, as, for instance, when the land is rough- or timbered or when the soil is so light and subject to wind that the danger of erosion forbids cultivation.

The improvement of pastures by resowing after an arable period not only can be carried out quickly, but also makes it possible to take advantage of recent advances in regard to strain differences within pasture species. Hence the improvement often may be made a double-feature one-the sowing of more valuable species such as rye-grass, cocksfoot, and clovers in place of brown-top, rib-grass, catsear, &c., can be linked with the use of the better strains that were not readily procurable when the pasture, if an old one, was previously sown down. The official system of seed certification has resulted in a dependable supply of such strains. When improvement of a pasture by renewal is being considered, it should be kept in mind that while lack of fertility is not always the cause of inferior pastures it frequently is so. If a pasture is inferior because of the lack of fertility under which it exists, then it is of prime practical importance to bear in mind that the mere sowing of seed fitted to give a good pasture will not necessarily give such a pasture ; if improved fertility by means of such practices as top-dressing and drainage is needed, then, until the fertility is suitably improved, the sowing of good seed will prove futile to a considerable extent. In practice this seems sometimes to be completely overlooked. For instance, a pasture which is of low production and poor composition is broken up and arable crops which impoverish the land are grown before the area is again sown in grass. Really in such circumstances it is unreasonable to expect an improved permanent pasture until the fertility is made greater than it■ was prior to the impoverishment by the exhausting crops. It follows that in the circumstances cited any cropping prior to the sowing of the permanent pasture should be fitted to increase instead of to exhaust the fertility of the soil. This common-sense course is reversed in those numerous cases in which such crops as oats, maize, and millet precede permanent pasture in land the fertility of which prior to these crops tends to be inadequate for the type of pasture it is desired to obtain ; the crops named and similar ones in general reduce fertility, especially when they are not consumed where they are grown. If land is worn out to some extent by cropping prior to the sowing of permanent pasture, then a liberal fertilizing of the young pasture in its early stages becomes particularly advisable. July Top-dressing. Extensive field experience has taught that top-dressing, if not already done, may be carried out with good results in July. In many of the main dairying districts, even in the case of wet relatively cold soils, superphosphate applied in July may be expected to bring about useful increases in the amount of feed available directly from the pastures in August. When speedy benefit from top-dressing is desired, as it usually is, then superphosphate ordinarily should be used, and in districts in which liming is profitable lime should be applied shortly before or at the same time as the superphosphate if benefit from a previous liming is not still being obtained. On many occasions in these notes the application to grassland of superphosphate and of other phosphates much earlier in the year has been recommended. That recommendation continues, but many who have not top-dressed or not top-dressed enough prior to winter would be wiser to do it in July or thereabouts than to do no further top-dressing during this year. If the weather conditions do not lead to an unusually late commencement of increased growth-rate of grass in the new season, then the application of sulphate of ammonia or similar nitrogenous fertilizer about mid-July to suitable pastures may be expected to result in a substantial increase in the feed available from treated fields in August and September, but for a few weeks prior to mid-July it is usually inadvisable to apply such nitrogenous fertilizer. ' As a general rule superphosphate should be used in conjunction with sulphate of ammonia. Whether sulphate of ammonia or similar

nitrogenous manures should be used in the manner just specified is determined to a considerable extent by how acutely additional early feed is needed. A further question likely to arise is whether the necessary additional feed could be obtained more cheaply than by the use of a quickly acting nitrogenous fertilizer. . . ■ ■ .

Harrowing and Spelling of Pastures.

Harrowing of pastures usually calls for widespread attention in July, when it is particularly advisable to break up and distribute thoroughly droppings on fields which have been heavily stocked during May and June. To bring about thorough distribution a section of chain-harrow attached behind the grass-harrow generally proves of value. r

As a means of avoiding early setbacks it is very desirable to have attractive suitable feed available for early-calving cows and for early-lambing ewes. To provide such feed it often is very advisable to shut up in July suitable pastures, preferably ones which are well drained and sheltered and in which rye-grass is prominent. An immediate top-dressing of such pastures with superphosphate, if they have not been top-dressed prior to winter, is likely to be of assistance. ' ■ ■

Trampling of wet soft paddocks leads not only to direct loss of valuable plants by burial, but also to the possibility of the establishment of such weeds as thistles, docks, rushes, buttercups, and daisies on the bare surface soil which results from the burial of valuable components of the pasture. Among the main ways of reducing the damage from trampling to a minimum are —(1) The stocking of wet areas as little as possible ; (2) the feeding-out of hay; &c., on the drier portions of the farm, which often are the poorer portions that benefit most greatly from the increased fertility that feeding-out gives; (3) the feeding-out of hay, &c.,. on the poorer pastures which are soon to be put to arable use.

Arable Cropping.

As a rule, the sowing of seed in July in inadvisable. Hence if wheat cannot be sown by about mid-June the sowing usually may with advantage be deferred until August, unless the doing of this seems likely to lead to a subsequent embarrassing rush of work. ■ ’ Every opportunity should •be taken to go ahead with cultivation in preparation for the spring sowing of cereals, mainly in the August-September period, but the harm to the tilth of the soil which results from the tillage of heavy wet soils should be avoided. ...

.Asa means to more profitable feeding of,stock, two crops which, having regard to their merits, are much neglected are lucerne and mangels. -The 1935-36 Dominion acreage of mangels was considerably above, average acreage for the ten years ending at the 1935-36 season ; definite figures are not yet available relative to the 1936-37 acreage, but . reports from seedmerchants suggest an appreciable decline. A decline is directly contrary to the needs of the position unless other feed to replace that yielded by the mangel is being provided,■ but of this .there is no evidence. It has been stated that recent changes in the. farm-labour position are adversely affecting the area devoted to arable crops . generally but especially that devoted to the mangel. In this connection it should be remembered that the well-managed highly productive mangel crop can remain distinctly profitable. when loaded with labour charges great enough, to make many other crops unprofitable. Mangel crops of 60 tons an acre or more are so common that it is clear that when conditions are suitable for mangels a 60-ton-an-acre crop is not an exceptional achievement. When hay is worth a ton, then mangels are worth at least 10s. a ton, so that the value of a 60-ton. crop is £3O an acre—a value which after allowing for other charges leaves a substantial sum for labour costs. ' . . . z

The outstanding value of lucerne has been demonstrated convincingly by farm results in many districts. New Zealand experience confirms that of other countries in that it shows what a definite misconception it is to believe

that lucerne is particularly exacting in its requirements : it. has been found in New Zealand that lucerne succeeds on practically all types of naturally well-drained soil, ■ and that there ■is a profitable role for lucerne at least whenever a dry summer spell causing a shortage of green non-stemmy feed from pastures is expected fairly frequently.

Lucerne may with advantage follow old pasture,, and if it does so, then the land should be skim-ploughed well ahead of the time of seeding, and subsequently ploughed deeply once only. Detailed guidance regarding lucerne-culture is contained in this Department’s Bulletin .155, available for free distribution. . ,

—R. P. Connell,

Fields Division, Palmerston North.