Spring-sown Crops and Pastures: Drain Maintenance

New Zealand Journal of Agriculture, Volume 85, Issue 2, 15 August 1952, Page 143

Spring-sown Crops and Pastures: Drain Maintenance

Seasonal Notes by the Extension Division

■CVERY opportunity should be taken of favourable weather at this season to proceed with the preparation of land for spring-sown crops and pastures. Production of meat and dairy produce could be increased on many thousands of farms on ploughable land if a systematic plan of pasture renewal were undertaken and inferior swards ploughed up, sown in a winter fodder crop, and resown with highly productive strains of Certified grass and clover seeds. Almost every dairy and fat-lamb farm contains one or more fields where the sward has become unproductive for one reason or anothertoo-frequent haying, grass-grub attack, too much or too little grazing for long periods, drought or flood, or lack of topdressing or liming. Often some fields can be rejuvenated by management or possibly by oversowing, but the quickest and best method if the sward is seriously lacking in desirable species of grasses and clovers is to plough and resow it.

AUTUMN AND SPRING SOWING OF PASTURE

Whether pastures to follow a winter root or fodder crop should be spring or autumn sown is freouentlv debated.

buvvii ib irequeiiuy ueutiteu. Early-autumn sowing (preferably after a summer fallow) is generally considered most satisfactory in districts where early frosts are not likely to damage seedling clovers. In some drier districts autumn sowings are risky because of the likelihood of light rains after sowing being followed by a prolonged dry spell. Late-autumn sowings are risky in nearly all districts because cold and wet winter conditions retard the growth of the establishing seedlings.

Spring sowings usually establish rapidly because of abundant moisture, but annual weeds are often a problem. Some of them, such as spurrey, fat-hen, and wild turnip, are eaten readily by sheep and may be controlled by rapid grazing by large numbers of animals. Where that is not possible, mowing the weeds before they smother the grasses and clovers is advisable. On the whole, spring sowing is satisfactory provided wet weather does not delay cultivation for so long that the seed is sown just before the onset of dry weather.

SOWING UNDER COVER CROPS

Sowing down of pasture with a crop such as rape, oats, or wheat is common in arable farming areas. It has the

advantage that one set of cultivation operations suffices for the sowing of both crop and pasture. However, cover crops have two great disadvantages: First, the cover crop may grow so vigorously that it partially or completely smothers out the establishing pasture; and, second, the pasture may be damaged severely during the feeding off of the cover crop. Therefore the use of cover crops is justified only when the pasture species will not be damaged by smothering or grazing and is undesirable on high-fertility land. On medium-fertility land cover crops are sometimes of considerable value to an establishing pasture composed of slower-establishing plants such as cocksfoot and red clover. The presence of light cover in itself delays the time of grazing until much later than if the time for grazing was determined by the stage of growth of the ryegrass in the mixture.

SPRING SOWING IN THE NORTH ISLAND

In many of the northern parts of the North Island paspalum is an ) important constituent of swards on dairy farms. Warm condi-

tions and a minimum of competition from other plants are necessary for it to establish successfully, so paspalum sowings should be delayed until November or December. It establishes well with November-sown root crops or with millet. Where paspalum is not included pasture is sown as soon as the weather becomes warm in spring.

The aims of working down should be consolidation and conservation of moisture. Both of these are best brought about by early-winter ploughing, which conserves moisture, and by early preliminary working, which assists consolidation. The final seed-bed for normal sowings should be fine, but for early sowing a very fine seed-bed should be avoided, as it is likely to pack down or crust in wet weather.

—S. H. SAXBY

* PREPARATIONS FOR RAPE CROP

** . e THE summer forage crop grown most extensively in New Zealand now is rape. Not only does it give a

good yield of feed under most conditions, but it also plays an important role in the preparation of land for autumn-sown wheat. Rape seed is small and requires a firm, fine seed-bed for best results. To ensure this early-winter ploughing is advisable in most districts. As the crop grows during summer, one of the prime considerations in seed-bed preparation is regular harrowing to kill weeds and conserve moisture. To reach maturity rape takes 12 to 14 weeks on heavy land and 10 to 12 weeks on the lighter soils. Times of sowing may be staggered between October and January to meet feed requirements.

CERTIFIED RAPE SEED

Certified seed of three types of rape is available to growers through mercantile channelsßroad Leaf Essex, Giant, and Club Root. Resistant.

k?IUU IVUUU XVCDJLb LcllJL L. Broad Leaf Essex is a relatively short-growing, dense type with a small, fleshy stalk. Its initial growth is not as good as that of Giant, but it has powers of recovery after even two or more grazings. Giant is a tall-growing type with a heavy, woody stem when mature. Its initial growth is better than that of Broad Leaf Essex, but it does not recover well after being grazed. The period of suitability for grazing is less critical with Giant than with Broad Leaf Essex.

Club Root Resistant is a comparatively new release which has a definite resistance to the effect of club root infection. The type of plant resembles Giant, but it produces less. Its main value is its ability to produce a valuable feed crop in club root-infected land where the other types would fail.

—O. G. MOORE

MAINTENANCE OF DRAIN OUTLETS

* * ANNUAL maintenance of drainage 7 systems to ensure that they function efficiently is essential. The most imnnrtjint nart.c nf n Hrninfurp

lIIObL important parts 01 cl system, whether it be of tiles, slabs, stones, or fascines, are the outlets, and these should be inspected each autumn to ensure that they are not choked with weeds and earth or trampled in by stock. The ditch into which they empty must enable the water to get away quickly and not back up over the outlet. If it does, the ditch should be deepened or widened to prevent this happening again, as immersed outlets cause silting and early breakdown of the drains. Outlets should also be inspected during winter while water is flowing from them to ascertain whether any undercutting is taking place; if so, it should be repaired immediately. The best method is to cement the last two or three tiles together and pack them tightly with earth and sods. If the undercutting is too advanced to be dealt with at the time, water should be prevented from cutting back any further by placing a board for the water to flow down until a permanent repair can be made in early spring. The sods used can then . consolidate and the grass take root before the following autumn.

K. L. MAYO