Topdressing in Auckland Province

New Zealand Journal of Agriculture, Volume 60, Issue 1, 15 January 1940, Page 23

Topdressing in Auckland Province

Review of Field Experiments In Waikato District

J. F. SHEPHERD,

Fields Instructor, Hamilton

IN the Waikato, perhaps to a greater extent than in any other part of the Dominion, the topdressing of pasture land plays a striking part in the maintenance of production. In fact, it may be said with a great deal of conviction that the Waikato owes much of its prosperity as a dairying, and fat lamb producing area to the fact that farmers in that district have quickly appreciated the great aid that manure can offer in building up pasture production. Early Topdressing ■ When 'topdressing was first introduced the fertilisers used were almost entirely phosphatic. In the main, these were bonedust and basic ‘ slag. Our present nearby supplies of rock phosphate and a product of these—superphosphate—were then practically unknown to New Zealand farmers. However, with the outbreak of war in 1914, European supplies of basic slag were cut off,' while the rapidlyrising cost of bonedust made its use for pasture topdressing quite prohibitive. As a result, other supplies of phosphate—chiefly rock phosphatehad to be obtained, and, from these, increasingly large quantities of superphosphate were manufactured. Thus, superphosphate . became the standard manure, and, through its general efficiency, it has retained a position* of pre-eminence in the Waikato.

While phosphates were satisfactory over a wide area, it was found that there were localities which did not respond well to straight phosphatic manures. Results in some districts were even very disappointing. Consequently, in an endeavour to get better results, many farmers adopted “hit or miss” practices of including quantities of lime, potash, and nitrogenous manures in their mixtures.. Where these succeeded all was well, but very frequently their inclusion resulted in

little or no change in the pasture position, but certainly in a distinct loss ,on fertiliser to the farmers concerned. Obviously the choice of fertilisers for ■ ' ■ - a particular locality should be based on some foundation of knowledge concerning the particular requirements of that area. Chemical analyses do not supply that knowledge in such a way that it can be readily used by the farmer, but a study of soil types,, coupled with

an examination of field experiments laid down on these soils, does much to elucidate the correct manurial procedure for . any locality. Waikato Soil Types So far as the Waikato is concerned, there are several main soil types, with many variations. Briefly, these main types are: d (1) Clays and Silts. . (2) Clay Loams and Loams. (3) Sandy Loams and Sandy Soils. (4) Peaty Loams and Peat Soils. Of these types the clay and silt types are represented by much of the rolling

country in the Te Awamutu, Hamilton, and Morrinsville districts. On these soils the. response to phosphate is good, but is further improved by liming. Clay loams and loams are alluvial deposits which are fairly heavy and hold soil moisture well. They respond very well to phosphates and lime. Where these soils gradually merge into sandy deposits the addition of potash has a beneficial effect. Generally speaking, however, the soils indicated in Groups (1) and (2) above are most economically manured by applying 3 cwt. to 6 cwt. of superphosphate with 5 cwt. lime per acre annually on all dairying lands, or on those farms having a high concentration of sheep. The following table will indicate the results obtained from a number of experiments carried out on these soil types.

The sandy loams and sandy soils of Group (3) are river deposits of varying depth and fineness. In places these merge into other soil types, but, on the whole, are in fairly well-defined areas. On these soils the response to phosphate is quite satisfactory, but is improved by the addition of potash and lime. In other words, a dressing of all three manures is the most efficient bn these soils. In many respects the peaty soils closely follow the sandy soils in manurial ' requirements. Here, too, a manure containing phosphate, -flash, and lime is required.

However, while the sandy soils do respond to phosphate alone, the peats give a most disappointing result unless lime and potash are also applied. In fact, it could be said that manuring with phosphate alone is uneconomic on these soils. In Table 2 a number of experiment results are set out: —

Conclusion Summarised, the position in the Waikato is that phosphates generally are necessary for pasture production. In fact, they are essential, and, _■ in the main, a quick-acting form such as superphosphate is desirable. On all clayey, silty,' loamy, and sandy soils, some immediate response from phosphates may be expected. .

However, on all these soils the addition of lime improves production, while, on the sandy, soils, potash is also necessary for highest returns. On the peats, phosphate must be supplemented by lime and potash before payable results may be expected. Acknowledgements Thanks are due and tendered to the above-mentioned farmers and many others for their co-operation in conducting field trials; to officers of the Soil Survey Division for their classification of soils; to Fields Division officers who carried out the various experiments; and to Mr. H. Drake for photographs illustrating l this article.

Kudzu Vine

A.T.W. (NEW PLYMOUTH):— Is the Kudzu vine palatable to stock? Would it be suitable for growing on an island in a river subject to inundation and at present carrying a growth of tall fescue and convolvulus, with some gorse and blackberry? i, . Are cuttings of the vine procurable to New Zealand? Is the vine winter-dormant, and would it be suitable for a rough runoff for dairy stock? If you could reply through the “Journal” I am a constant reader. FIELDS DIVISION:— 1 This plant has not been introduced into New Zealand, and cuttings are therefore not available. The conditions under which it grows, and is used in the United States indicate that it would have possibilities only in the far north of New Zealand. The vine is winter-dormant, and' frosts entirely kill off the summer growth. It is said to be suitable for rough summer feed for cattle, but does not stand continuous grazing. I do not think it likely to prove of great value under the conditions mentioned. For these conditions, namely, an island in a river subject to inundation, I would recommend planting the area with pampas grass and using this plant for a winter run off for cattle. Pampas . grass is already being used successfully on blackberry and gorse-infested areas adjoining some of the rivers in Taranaki.

• •U—.MM—-Illi—llli—.llll—.nil—.11,1—Illi—mi—Illi—.1 •£• The Waikato district is selected I for discussion in this, the 1 second of a series of articles I on topdressing practice in I various parts of the Auckland j Province. Summarised, the | | position in the Waikato is that j j phosphates generally are neces- j | sary for pasture production. j I •Jtii— mi— mi—mi—mi—mi—.mi—ini— uu—Rtjfr

Farmer. ■. . Soil Type. ' . Improvement Over No Manure. ’ . . . Lime. ■ Super. Potash. Lime -J- Supei A. Parkin /.■_ Hamilton Clay . Slight ■ Fair Nil Good C. J. Pierce . . ■ Ohaupo Silt . . Slight Fair Slight V. Good F. D. Maisey . . . Clay/ ... ’ .'. Slight ■ V. Fair Slight Good ‘A. Lovett . . . Olay Loam 1 . ’ Slight . Slight ’■ • Slight . ' Good R. Chilcott' /. . .■ Clay Loam ... • Slight ■ V. Fair . V. Slight V. Good IT. Lee ■ ' . . Clay . . .. Slight Fair V. Slight Good ' F. S. Hill . Clay Loam . . ' Slight Good Slight , V. Good

TABLE 1.

Farmer. •. Soil Type. Improvement Over No Manure. Lime. Super.' Potash. Lime + Super 4- Potash. A. G. Boyd Sandy Loam . . Slight Slight Fair Excellent N. Reid Sandy Loam . . Slight Fair - Fair Excellent S. Reid Sandy Loam . . Slight Fair Slight Good K. S. Gorrie . . Sandy Loam . . Slight . Good Slight V. Good R. S. Ranby . . Peaty Loam . . Slight ■ • ■ - Slight Slight. .. t . Good A. B. Bishop . . Peat . . ' Slight Slight Fair V. Good A. / G. Howe Peat . . Fair Fair ■ ■ Slight V. Good F. W. Thomas Peat . . ' . . Slight Slight - Slight Good F. N. Howe Peaty Loam . . Slight Fair Slight Good

TABLE 2.