GRASSING OF CONSOLIDATED SAND AREAS, NORTHERN WAIROA, NORTH AUCKLAND.

New Zealand Journal of Agriculture, Volume 54, Issue 6, 21 June 1937, Page 328

GRASSING OF CONSOLIDATED SAND AREAS, NORTHERN WAIROA, NORTH AUCKLAND.

E. B. Glanville,

Instructor in Agriculture, Whangarei.

Farmers are always interested in virgin land that can be quickly and cheaply converted into good pasture-land, and the consolidated sand areas of the Northern Wairoa offer considerable scope for development in this direction. The extensive grassing-work carried out in the development of this land for settlement under the Small Farms Act has shown that good permanent pastures can be quickly established on this land, provided the soil is carefully cultivated, permanent species of grasses and clovers are sown, and the pastures adequately manured with superphosphate. . Mr. N. H. Taylor, of the Soil Survey Division of the Department of Scientific and Industrial Research, who, at my request, made a brief examination of the area, supplied the soil map and wrote the following sections dealing with topography and soils. Location and Climate. The district referred to in this article as the sand country of the Northern Wairoa is a strip of land fifty miles long and approximately five miles wide, extending from Mangonui Bluff to Kaipara North Head, and lying between the Kaihu and Wairoa Rivers on the east and the sea on the west. The mean annual rainfall for the district is 50 in., with 150 rainy days per annum (1). The mean monthly temperatures vary from about 63° F. in January and February to 50° F. in August(2). The area is swept by the prevailing westerly winds. • Topography. The greater part of the district (a strip along the western side two to three miles wide) is an area of flat-topped spurs and steep-sided valleys, the floors of which are occupied by peaty swamps. In the north the flat-topped spurs reach heights of 400 ft. and 500 ft., but farther south few rise more than 300 ft. above sea-level. West of Mamaranui, where the streams are closely spaced, the bleak, scrubcovered spur-tops and steep valley-sides, scarred with white slips, present a most dismal appearance, but west of Dargaville, where the land is lower, broad flatfish spur-tops are the most conspicuous features of the landscape. The whole of this area is underlain by consolidated water-sorted sands, interbedded with which are small lenses of lignite. On the west the water-sorted sands are buried by drifts of wind-blown sand, but they appear again in an almost unbroken line of cliffs bordering the shore.

The blown-sand country of the west is of three types : (i) The older . fixed dunes; (2) the younger fixed dunes; and (3) the bare sand-drifts. :

The older fixed dunes form a belt of rolling country about a mile wide extending from 'Kai Iwi Stream to the Tikinui coast road, a distance of about twenty-eight miles. The hills are smoothly rounded and the sand is permanently fixed by weathering. The younger fixed . dunes cover a wedge-shaped strip thirty miles long, lying south of the older fixed dunes. The country, though described as rolling, is more broken than the area covered by the older fixed dunes, for the hills still have the typical dune shape with irregular crest lines and steep lee slopes. The sand is fixed by vegetation, but weathering has not yet fixed the dunes permanently. The bare sand-drifts (Fig. 2) cover about, thirty square miles of the country close to Kaipara North Head, and northwards they taper to a strip flanking the shore, rarely more than half a mile wide. Sand thrown upon the shoie by waves is carried inland by the wind, where it accumulates as dunes, which move steadily forward. While they are growing the dunes have a regular shape (steep lee slopes and gentler slopes to windward), but farther inland, where the supply of wind is less regular, the dunes become fixed in places by sand-binding plants and are scoured by the wind into forms resembling miniature mountain ranges. Both the bare drifts and the younger fixed dunes lie athwart the drainage of the older country and! dam back the streams to form lakes and ponds (Fig. 3). Soils. As the soils throughout the area are somewhat similar in composition and the . climate fairly uniform, the . main factors leading to soil differentiation are —(1) The covering of vegetation; (2) the topography; (3) the time that has elapsed since the various sand deposits were laid down. Under a humid climate the rock material decomposes and the soils which form tend to become leached. The vegetation gathers mineral substances from the soil and these are returned to the surface as the leaves die and fall. The vegetation, in this way, tends to work against the rainfall. ■ Topography is important, for on steep slopes the soil tends to be eroded as fast .as it is formed. The area is one which has been subjected to many scrub fires, and on this account much of the soil has been eroded. Washing by rain and slipping have removed much of the soil from the steep! slopes, and in many-exposed localities the unprotected soil has been so completely removed .by the wind that : the bare sandstone appears at the surface. Fires and over-grazing with stock, by destroying the sand-fixing vegetation, are also assisting, the advance !of the drifting sand. ) .- \ J The sand soils of the area have been mapped and are shown (Fig. 1) as belonging to five groups : (1) The Pinaki sand, which is classified as ! a skeletal soilthat is, a very young soil showing little alteration by : soil-forming processes ; (2) the Red Hill soils, classifed as podsolized soils, or soils which show a well-defined topsoil and subsoil, but; have not yet reached the stage of development attained by group 3 ; (3) the Te Kopuru sand, classified as a podsol* on

maturely developed soil; (4) the Tangatiki; and (5) the Kai Iwi soils, classified as complexes or areas covered by a patchwork of soils resembling those of groups 2 and 3. . The Pinaki sand is a young soil, derived from the sand of the younger fixed dunes. It consists of 3 in. to 6 in. of black sand resting on a brown free sandy subsoil. The soil is overdrained, and pastures on it are subject to drought in.dry spells. The Red Hill soils are those covering the older fixed dunes. The Red Hill sandy loam is a light-brown, moderately compact soil resting on lightly cemented sands. Over the western part of the area there is a shallow covering of more recent sand, and soils affected by this covering have been grouped together as the Red Hill sand. A typical profile shows 4 in. to 10 in. of dark-grey sand resting on the moderately compact brown sandy loam. In places the subsoil is darker brown, more clayey in texture, and presents the appearance of a weathered volcanic ash. This is probably due to the fact that at certain periods much of the drift sand has consisted of pumice particles which have been brought from the mouth of the Waikato River by ocean currents and cast ashore by the waves. The Te Kopuru sand is a soil derived from the older watersorted sands. The soil is a mature podsol developed under a former kauri forest. A typical profile (Fig. 4) shows 5 in. of grey sand, 5 in. of whitish sand, and 6 in. of a blackish humus pan on cemented sandstone, with iron and alumina pans at different depths. The acid humus collected under the kauri forest, leached throughout the ;soil,- carrying with it the iron and alumina and forming pans below. This soil is badly drained in winter,. and, on account of the sandy texture of the topsoil, is dry during the summer. This mature profile is best developed on the flatfish spur-tops and easier slopes. Where the slopes are steeper, slumping, takes place, and the soils are not so mature. The Tangatiki soils are complex ' soils developed on the southern part of the older water-sorted sands. . On this area the kauri forest did not form such a continuous . cover, and the soil pattern is a pat work of mature soils resembling. the Te Kopuru sand and brown moderately compact sandy loams, somewhat resembling the Red Hill sandy loam. On account of the steepness of much of the country, and because of the continual scrub fires, much of the soil has been eroded and in these places the sandstone is at, or near, the surface. The Kai Iwi soils are complex soils developed on the older fixed dunes, north of the Kai Iwi Stream. This area has in the past been partly covered with kauri forest. The soil pattern is a patchwork of Te Kopuru sand and Red Hill sandy loam.

Surface Covering.

The natural surface covering of the hill areas (Fig. 5), considerably modified from its primitive state, consists of light manuka scrub and bracken fern, with a sparse growth .of danthonia and bay grass (Eragrostis Brownii). On the - podsolized soils where drainage is bad, rushes and sedges cover considerable areas, while on the swamp areas flax is found growing in addition to strong rushes.

The following indigenous plants are found through the scrub and fern : Lycopodium densum, Cladium terfolium, Lepidosperma laterale, Halorrhagis procumbens, Microtis unifolia, Pimelca prostrata, Leucopogon Fraseri, Pomaderris phylicaefolia , and P. Edgerleyi. Of introduced plants Hakea pubescens and Erica stricta occupy much ground, while pines are numerous, and Ornithopus ebracteatus and Gnaphalium purpur are frequently met with.

Trouble is being experienced with moving sand encroaching on certain areas (Fig. 2), especially those exposed and adjacent to the sea-coast. Sand is being continually blown and swept from the beaches over the steep coastal cliffs on to the useful consolidated areas by strong westerly winds. Very successful work has been done to check and overcome this continual sand movement. Marramgrass (Fig. 6) has been found an extremely valuable plant for arresting sand movement and large areas are being planted each, year with great success.

Fertilizers.

The consolidated sand areas vary in. fertility • according to type, but are all deficient in phosphate ’ and nitrogen. Poor pastureswards (Fig. .7), consisting of stunted paspalum, Lotus hisfiidus, brown-top, . sweet vernal, tar-weed, and danthonia, cover a large .area of the Te Kopuru . soil type. These poor- pastures respond ■quickly to phosphatic top-dressing (especially basic slag), while applications of lime also give improved responses when used in addition. The fertility of this soil is extremely low, while the drainage is poor, and even with heavy applications of phosphatic ■fertilizers and . lime it is practically impossible to establish and maintain a high-producing pasture. Top-dressing will, . however, improve the existing sward, but it is doubtful if it is a payable procedure. \ . ' ' - On the other hand, the Red Hill sandy-loam soil type has good •drainage and higher fertility, which makes pasture establishment on this soil type an easier proposition. Considerable areas of this soil type have in past years been burned and surface sown. The resultant pasture-sward (Fig. 8) has been neglected, and the sward now 'consists of ratstail, danthonia, suckling clover, catsear, and in places paspalum—a very poor unpayable type of sward, for on this land . a first-class pasture consisting of perennial rye-grass, white •clover, cocksfoot, and paspalum can be established and maintained provided the necessary precautions regarding good cultivation, sowing good strains of permanent grasses, and using adequate supplies of phosphate are taken.

Experiments 16/1/226, 227, 228, and 229 were laid down during the autumn of 1933 ; at laying-down, plots received lime at 1 ton per acre, superphosphate at 3 cwt., and 30 per cent, potash salts at 2 cwt. per acre. At the end of two years and a half, fertilizer responses on Red Hill sand show .an excellent response (Fig. 9) to superphosphate, a slight additional benefit for lime when used with superphosphate and no response for potash. ■ -7 Experiment 16/1/98 (D) was laid down in July, 1929, and kept under observation until June, 1933. In this experiment basic slag and rock phosphate were used in addition to superphosphate. At

the end of four years fertilizer response on Te Kopuru sand show an outstanding response for basic slag plus lime, whilst basic slag alone was equal to superphosphate plus lime. Superphosphate alone gave a disappointing response, while no response was given for potash. Superphosphate on the Red Hill sand and basic slag on the Te Kopuru sand appear to be the best types of phosphate, while a good establishment of white clover is necessary to supply the nitrogen. The experiments show that there is a general lack of response to lime alone, but lime gives an increased response when used in addition to superphosphate and basic slag.

Grassing. The areas of Red. Hill sand, being younger, have not been leached to the same extent as the Te Kopuru sand. They make good dairying land and are being fairly rapidly developed for this purpose. The soil is light, not very well supplied with humus, and the development into high-class dairying pastures requires

careful cultivation aiming at a good firm seed-bed, followed by adequate phosphatic manuring. Grassing can be done in three ways :

(1) After clearing and burning, the land can be lightly surfacecultivated and a cheap temporary pasture-mixture consisting chiefly of Lotus hisfridus can be sown. This temporary pasture builds up fertility and makes subsequent permanent grassing easier.

(2) After clearing and burning the land can be ploughed, sown in permanent grass, and. fertility raised by heavy applications of phosphates. This method is dependent on a good initial strike of white —further phosphates encourage the clover and the clover in turn encourages the grass. For this method to succeed it is necessary that the land be ploughed early, cultivated thoroughly throughout the summer months to a firm seed-bed, and the grass and clover sown early in the autumn so that plants become well established before the cold winter westerly winds start to blow. (3) After clearing and burning, the land can be ploughed during the late autumn or early winter and then sown in root crops, such as soft turnips, for. summer feeding. Here, again, it is necessary to raise the fertility for successful permanent • pasture establishment by good cultivation and heavy applications of phosphatic fertilizers. This method is perhaps the most economicalthe Red

Hill sand grows excellent root crops, and soft turnips are ■' very valuable for feeding to the dairy stock from Christmas on through the summer months, when the pastures generally dry up through the inability of the soil to hold moisture. Cultivation is important. A good seed-bed for grass is clean, sweet, moist, fine, and firm at the time of sowing. The seed-bed must be consolidated from below up (Fig. io).

Experience has shown that the most suitable cultivation tor this sandy land preparatory to grass is to plough with a lea mouldboard plough, 6 in. deep (the better the ploughing the easier it will be for the subsequent work of seed-bed preparation). The soil should be fallow for at least four or five months to allow of weathering and good' aeration, and for the furrow-slices to close together. It is advisable to roll on the furrow with a Cambridge roller, to double disk to a fine seed-bed, followed by the tyne or chain harrows to level the surface. It should be rolled before sowing the seed and fertilizer, and the seed covered with light chain harrows and finally rolled again. Ploughing with a lea or long mouldboard plough is preferable to doing the work with a plough of the digger mouldboard type, as, with the former, subsequent consolidation is easier. Rolling on the furrow with the Cambridge roller is most important; rolling should be done in the direction of the ploughing, and the heavier

the roller . the better. This rolling consolidates the bottom of the seed-bed, and brings the soil moved by the plough in close contact with the unmoved subsoil, making a continuous firm layer of soil through which soil moisture may move from the deeper layers to the surface. There are' two main types of pasture established on the consolidated sand areas, viz. : (1) A paspalum - subterranean-clover pasture : .(2) A rye-grass - cocksfoot - paspalum - white-clover pasture.

The paspalum - subterranean-clover pasture (Fig. 11) is found where farming is carried out on extensive rather, than intensive lines and where only light top-dressing is practised. It is an excellent association where rye-grass is difficult to establish and maintain. Paspalum has good summer growth, whilst subterranean clover is an annual. It buries its own seeds, and the young plants live up to February-March. They grow well in the autumn, winter, and spring, grow vigorously in October, November, and December, and then wither and die. This association appears to be more suited to the Te Kopuru sands; it is fairly easy to establish, but the growth from subterranean clover is not very great on this poorly drained soil type. White clover is difficult to establish and maintain, and subterranean clover with Lotus hispidus and suckling clover forms a good companion for paspalum. The rye-grass - cocksfoot - white-clover - paspalum pasture (Fig. 12) is found growing vigorously in the Red Hill sand soil type. A

consolidated seed-bed (Fig. .13) with heavy phosphatic top-dressing is necessary to raise the fertility to a level required by rye-grass. The mixture sown to produce the sward illustrated in Fig. 12 consisted ofcertified perennial rye-grass, 25 lb. ; paspalum, 5 lb. ; cocksfoot, 5 lb. ; crested dogstail, 3 lb. ; red clover, 2 lb. ; and certified white clover 2 lb. per acre. . The whole success of sowing this mixture depends on using certified perennial rye-grass and certified white-clover seed. Before certified rye-grass and white-clover seed was available it was impossible to establish on these soils a dominant rye-grass pasture, for the short-lived strains of rye-grass “ went

out ” very rapidly. Heavy phosphatic manuring is also required—at least 3 cwt. of superphosphate per acre should be applied with the seed, followed by another dressing of 3 cwt. per acre three or four months later, and thereafter a dressing of superphosphate should be applied each autumn at the rate of at least 3 cwt. per acre. Treated in this way the pastures are capable of a butterfatproduction of up to 150 lb. per acre. Early sowing is also most important. This is a rule which can be adhered to for most soil types — not vzait for rain before sowing, this is not necessary if cultivation has been 'done thoroughly; for., good pasture establishment sow while the surface soil is dry, or when a cloud of dust is following the harrows. : "

Development.

During the summer of 1932 two large blocks of Red Hill sand areas were purchased by the Government and settled with unemployed married men under the Small-farm Scheme. The blocks. are shown on the plan (Fig. 1) as Wilson’s and Bassett’s blocks. Wilson’s block consists of twenty-one sections, and is situated •on the west coast about nine miles from Dargaville, while Bassett’s block, which consists of eleven sections, is situated farther south, about sixteen miles from Dargaville. Each section on both blocks consists of approximately 50 acres. Development work was carried out on these blocks during the autumn of 1933.

The results have exceeded all expectations, and the areas dealt with are now carrying an. excellent sole of grass consisting, mainly of rye-grass, cocksfoot, and white clover. The growth of grasses and clover has been so vigorous that paspalum has had little -chance to establish (Fig. 14). The carrying-capacity of these small farms is increasing rapidly, and the sections are now carrying up .to thirty milking cows producing up to 7,500 lb. of butterfat on the better sections. Subsequent management is along similar lines to other grassland—with heavy stocking and regular manuring, fertility is raised, more stock means more manure, more manure means more grass, and more grass means more live-stock can be carried. The Red Hill sand can be developed fairly cheaply.. The scrub covering is light, and if burnt off two years ahead of

ploughing the cost of clearing is negligible. Cultivation, allowing full costs for labour and feed, costs £2 to £2 10s. per' acre, grass-seed £1 10s. to £1 15s. per acre, fertilizer about £1 10s. per acre, fencing for fully developed farms £2 to £3 per acre, water £1 ios. 'to £2 per acre. This latter cost is most difficult to assess, as the land is naturally watered by creeks or lakes. Water generally has to be pumped to a higher level and then reticulated over the farm by gravitation. On Wilson's and Bassett's blocks a large engine and pump have been installed. The water is pumped into a ' large reservoir placed on a high hill, from

there it runs to each farm—drinking-troughs are placed in the various paddocks, and an ample supply reaches each section by gravitation. When developed and sown with good types and strains of permanent grasses and clovers the Red Hill sand areas should be useful country for fat-lamb raising and dairying. Recent work has proved that good high-producing pastures can be established now certified grass and clover seeds are available. The country generally consists of easy undulating hills, which can be easily ploughed. Not far removed from the sea-coast, it is situated in an excellent position when the health of sheep and cattle has to be considered. The land is healthy in winter and

summer, 'gives a good winter growth—although it may become somewhat dry during the summer months— is well watered with lakes, and is easy to road. Cultivation is easy and excellent root crops can be grown. Rape can be grown successfully, and a large area of the country gives one the impression that it would be . excellent sheep country, especially for fat-lamb raising. ~ Acknowledgments . ■ .. . . The writer wishes to thank Dr. H. H. Allan, of the Plant Research Bureau, Palmerston North, for the assistance he gave in identifying the plants found growing on the ’consolidated sand areas. \ References.

(1) E. Kidson ; Climate of North Auckland MSS., 1936. (2) Jour, of Sci. &■ Tech., Vol. XIII, page 144, 1932

*A podsol is a soil in which iron and alumina from the topsoil have been leached to lower horizons, leaving a bleached layer above.

Note the. bleached layer resting on the dark humus pan loin, to 15in. below the surface. The dark lines below the humus pan are iron pans. The unaltered sandstone appears in the bottom of the picture.

Experiment No. Soil. Responses to Fertilizers : 0, no response; 1, slight; 2, fair; 3, good ; 4, very good ; 5, excellent. 0, no response; 1, slight; zery good ; 5, excellent. 2, fair; Superphos- . 43 phate. 33 Lime. ft ft Potash. co SuperphosLime. phate Potash. Lime. plus Superphos-Superphos-phatephate Lime. plus Lime plus Superphos- Potash. plus phateslag: , plus Slag Potash. plus plus Slag. Slag ' plus Lime. 16/1/226 .. Red Hill sand . 4 I 0 41 41 /227 . . Red Hill sand. . 3 0 0 31 31 - . 16/1/228 .. Red Hill sand. . 4 - I 0 5 5 I6/1/229 • • Red Hill sand. . 4 0 0 4 4 16/1/98 (D) . Te Kopuru sand . 2 I 0 3 3 3 4

Fertilizer experimental work in pasture top-dressing carried out on these soils has given the following results :