Development of the Light Lands of the West Coast

New Zealand Journal of Agriculture, Volume 63, Issue 5, 15 November 1941, Page 393

Development of the Light Lands of the West Coast

Arable Crops for Sheep Is An Essential Factor '

By

A. D. MERCER,

Fields Instructor, Greymouth.

WHEN an old pasture of reasonable stock-carrying capacity and white clover-content is ploughed under in the ordinary course of mixed farming operations one may expect the following crop to benefit by the latent soil fertility, but disappointing results usually follow the breaking-up of the old matted turf of browntop, moss, and sweet vernal, which is characteristic of much of the light land of the West Coast district. This article suggests certain measures for dealing with the problem of bringing into production the tussock plains

'''IIIIMIIIIIIIiniBIH of the Maruia Valley, which lies between Murchison and the Lewis Pass, but similar treatment is indicated on the light land of Inchbonnie and on some of the Wataroa flats. All of this light land with varying depths of soil, some of it barely capable of supporting a sheep to the acre, is capable of maintaining four sheep to the acre on the better class land.

Limiting Factors

To bring land of this type to that state of fertility which will ensure good fodder crops or high production pas-* tures, it must first be subjected to heavy stocking by sheep in order to add the organic matter or humus that gives “body” to a soil. The tussock plans which comprise a considerable area, of the Maruia Valley offer great opportunities for improvement. There is no initial expense of clearing and draining, and the land is all ploughable. but a certain capital outlay is involved to tide over the first two years of development. As previously stated, heavy stocking with sheep is necessary, but this is impossible on the sparse natural herbage, while the experience of one enterprising farmer on this country has

shown that the first crop of soft turnips or rape is not good enough to ensure adequate stock concentration. As all farmers are aware, the limiting factors to successful ' crop growth on most soils in New Zealand are lime and phosphate, but in this case both were supplied in ample measure. The result is partial failure, and it appears obvious that nitrogen must be supplied in addition to secure success in the first crop. The “golden hoof” will see to the rest.

Methods of Supplying Nitrogen

(a) Topdressing. The obvious method is to apply l|cwt. per acre of sulphate of ammonia with the rape or turnip crop, or 2cwt. of blood and bone. Sulphate of ammonia is now

unprocurable, while the price of blood and bone is very high. Nitrogenous topdressing is out of . the question today. (b) Leguminous Forage Crops. root crops are unsuccessful, an alternative first crop might . be ; oats for autumn green feed, and the chance of success would be vastly improved by the addition of one-half to one bushel of blue lupins to the feeding. - This legume, by the fixation of atmospheric nitrogen, would not only benefit the oat crop, but subsequent decay of the roots would add to the store of soil nitrogen, while its deep-rooting habit penetrates and aerates the subsoil. This, or a similar cereal-legume mixture, is likely to provide more feed under these conditions than the rape or turnips. .

. (c) Inducing- a Clover Sward Before Ploughing. treatment of poor pasture for two years before turning it over would, where time' is not a prime consideration, do much to alleviate. the nitrogen deficiency. A dressing of one ,ton of lime per acre plus 2cwt. of superphosphate not only encourages the growth of volunteer white clover, but also hastens the decay of the old turf when ploughed in. ~ In a sour soil this old turf will remain unchanged for years, but a liberal prior dressing of lime will bring about those conditions necessary for its decomposition and conversion into humus and eventually to available nitrogen. The establishment of clover may be hastened by the surface-sowing of subterranean clover, which on these plains

has succeeded admirably where lime and superphosphate have been applied. On one area, no lime —no clover. Surface-sowing of white clover in the spring should, in this district, prove equally effective. Whatever the means, adopted, they are all designed to the same - end, namely, the establishment of a tolerable amount of clover before breaking up in order to ensure soil fertility for later crops.

Following Crops

Whether the course followed is the cereal-legume green feed or the pretreatment of worthless grazing, ploughing for the next stage should be completed by the end of June, taking advantage of the beneficial action of the

frost and securing a good seed bed for rape or turnips. Rape fed off in January would leave time for an early autumn sowing of Italian ryegrass and red clover, which would provide valuable feed for the flock in early spring and for two years afterwards. Turnips fed later in the autumn would entail spring sowing of the seeds as soon as weather permitted, making green feed available well on in the summer when natural pastures are drying off. The useful life of such grazing is two years; when the area may be sown down to permanent grass. The gradually-increased stock-carrying capacity and the accumulation of fertility brought about by the concentration of sheep will maintain a productive pasture capable of supporting at least four times the present number of stock.

Maintenance of Fertility

Once the first hurdle is surmounted namely, the problem of sufficient feed to carry a heavy concentration of stocksubsequent maintenance of fertility is a matter of efficient stock management, bearing in mind the following points: Of the main elements essential to a fertile soil, nitrogen, potash, phosphate, and lime, very little is removed by grown fattening animals, either beef, cattle, or wethers. Considerable quantities of phosphates and calcium are, however, ' retained by dairy cows and ewes with lamb, but with all classes of grazing stock most of the potash returns to the land in the urine. Sheep feeding off roots or green crops return to the soil ninetenths of the nitrogen in the drop,, so that once a sufficient store is accumulated. dressings of phosphatic fertiliser and lime periodically will maintain the balance. ' , When good pasture is finally established. one ton of lime per acre every four years plus 2cwt. of superphosphate every , second year will complete the transformation of these plains from inferior sheep grazing to good sheep and cattle country.

Summary

Old. inferior' grazing country does not possess the stored-up fertility usually associated with pasture land. In addition to the usual deficiency of lime and phosphate, this type of country is likely to be lacking in available nitrogen, resulting in crop

failures when broken up for roots or ■ rape. .> " ■ This deficiency may be made good by the manorial action of heavy concentrations of sheep, but the difficulty in the initial phase is to secure sufficient feed for this purpose. As nitrogenous topdressing is imi practicable at present, two alternatives present themselves: — (a) A change from the cruciferous first crop to a sowing of oats and lupins for autumn green feed. (b) Prior treatment of the sward with lime and . phosphate to v induce , clover growth, and possibly surfacesowing of subterranean or white clover.

Answer to Correspondent

Crops for Winter Feeding Pigs

“COCKY” (WAIKATO),— I would be much obliged if you could give me some advice on the best crop to grow for the winter feeding of pigs. I find it exceedingly difficult and expensive to keep the pigs growing from the time the milk falls off in late autumn until the cows flush up again in the spring. I have a piece of drained peat swamp that has now consolidated, and having had it cleared of stumps and timber have started to plough it. I would be grateful if you could advise me what crop would give the best results under the above conditions, and any further information as regards amount of seed and manure and wh'in to plant. The area of the land is about two acres. FIELDS DIVISION— Maize for cob would be the most satisfactory crop for the purpose required. This crop requires a thoroughly cultivated seed bed and a soil that is naturally rich or well fertilised. Sowing should be done during November, and drilling can be done 14in, 21in, or 3ft apart. If 3ft apart, pumpkins, marrows, or kumi kumis can be grown between the rows. 1 Seeding at the rate of 25 to 301 b per acre is recojnmended. A suitable fertiliser consisting of three , parts superphosphate, one part blood and bone, should be applied at not less than 4cwt. per acre. \