Spring Topdressing and Spring Cereals

New Zealand Journal of Agriculture, Volume 93, Issue 1, 16 July 1956, Page 39

Spring Topdressing and Spring Cereals

Seasonal Notes by the Extension Division ■pARLY autumn is generally the best time to apply both phosphate and potash to pastures. These fertilisers stimulate the clovers and the more vigorous clovers help to supply the grasses with nitrogen in winter and early spring. There are, however, many occasions when phosphate, potash, or both can be used very profitably in spring. On high-phosphate-fixing soils where heavy dressings are needed to keep the pastures producing at their best it is wise to apply half in autumn and half in spring. This can be done any time from August to October, paddocks being treated in turn as they are grazed. Paddocks which have been shut up for autumn-saved grass will also often benefit to a marked extent from an application of phosphate immediately after they have been grazed off, particularly if the clovers have been knocked back by the smother of long grass. In the same way many farmers get a marked response to an extra spring phosphate dressing on pastures cut for silage because the clovers have been given a setback and the phosphate stimulates their recovery. On soils where potash gives a response the addition of potash to these spring topdressings is well worth while. It is generally much cheaper to supply the grasses in the pasture with the nitrogen they require by maintaining vigorous clovers with the application of phosphate and potash in spring as well as in autumn than it is to topdress with nitrogenous manures. There are times, however, when application of nitrogen is well worth while, , but this is seldom so in spring or early summer under normal conditions. If, ,however, growth is held up by unusually cold and wet weather, there is nothing like a dressing of nitrogen to bring growth away. —C. J. HAMBLYN * * *

NITROGEN FOR GRASS SEED

RECENT practice in the ; use of nitrogenous fertilisers for increasing the yield of grass seed crops can generally be justified from the

immediate financial return. Whether it is desirable to topdress perennial, short-rotation, or Italian ryegrass crops will depend on the appearance of the sward at the time of shutting up. Thus a yellow, sickly, nitrogen-starved pasture should give remarkably payable results from a topdressing of 2cwt. of sulphate of ammonia or an ammonium nitrate-lime mixture. On the other hand the use of nitrogenous fertilisers on a healthy, vigorous sward of dominant ryegrass on very fertile land may cause clover suppression. Between these two extremes are the crops which would benefit from lewt. . of nitrogenous fertiliser. Crops in their second and subsequent seasons are generally more in need of nitrogenous topdressing. Application should generally be at the time of shutting up. Either type of nitrogenous fertiliser (sulphate of ammonia or an ammonium nitrate-lime mixture) is suitable on many soils, both giving equal responses. However, consideration must be given on sulphur-deficient soils, as in North Otago and elsewhere, to the superior merits of sulphate of ammonia in increasing grass growth through the nitrogen and also in improving the clover content of the sward through the response to sulphur. On

most reasonably good cocksfoot stands topdressing in autumn and in spring at 2cwt. per acre each time of either sulphate of ammonia or an ammonium nitrate-lime mixture has proved payable, responses'being evident not only in increased seed yield but also in improved germination and purity of seed. Experience has shown, however, that weedy, run-out stands of cocksfoot do not repay nitrogenous topdressing. —P. R. BARRER * * *

SPRING-SOWN CEREALS IN SOUTH ISLAND

IN Southland the majority of cereal crops are sown in spring; in Canterbury and Otago most of the wheat is sown in autumn and some of the

oats and most of the barley in spring. Generally land intended for spring-sown cereals should be given thorough cultivation, and it should be liner on the top than is usually necessary for autumn sowing. If cereals follow swedes, it is not always necessary to plough. A satisfactory seed-bed may be obtained by thoroughly discing and working with a clodcrusher and harrows. The most popular variety of wheat for spring sowing is Cross 7. Another variety suitable for spring sowing is Hilgendorf and a bonus is paid by millers for this wheat, as it has a very high baking score. Wheat should be sown as soon as the land can be prepared in August. Sowing may be done into September or even early October. However, it should be done as soon as weather and soil conditions permit. The general seeding rate is 2 bushels per acre with 1 cwt. of superphosphate, but in Southland 3 bushels per acre is usual with 2cwt. of superphosphate.

OATS

Oat growing has declined in popularity in New Zealand, so that it has become necessary to import both feed and milling oats from

Australia. Excellent oats can, however, be grown, the most popular variety being Onward. Unfortunately, these oats are very prone to stem break. A more .recently introduced variety is Milford, which is resistant to lodging. Other varieties available for. spring sowing are Abundance, Royal Scot, Achilles, Spitfire, Forward, and Russet. The sowing rate for oats is 3 to 4 bushels per acre. The heavier seeding rate is usual in Southland. Discretion should be used in the quantity of fertiliser applied. If lodging is probable, it is advisable to sow without fertiliser, though this usually means later maturing and consequently later harvesting of the crop. Application of phosphate tends to hasten maturity. Oats should be sown early in spring, in September if possible, and generally not later than the end of October.

BARLEY

Barley growing is restricted almost entirely

to Canterbury and Otago. Land intended

for barley should be in good heart and well worked. Sowing should be undertaken in September and early October when conditions' are right for steady, uninterrupted growth. Popular varieties for malting are Research and Kenia; Golden Archer, Chevallier, Spratt Archer, and Plumage Archer are grown to a limited extent. The sowing rate is usually 2 bushels per acre with superphosphate at lewt. to 2cwt. per acre according to the fertility of the paddock.

—W. FAITHFUL