Drought management Encouraging pasture growth

Press, 1 September 1989, Page 22

Drought management Encouraging pasture growth

Overdrilling is the cheapest and most efficient method of encouraging drought and grass grub ravaged pastures back into production, says a MAFTech consultant at Fairlie, Mr Bruce Beckingsale. In very badly droughtaffected districts, pastures will be virtually dead after the drought and in need of rejuvenation. Apart from parts of a farm going through normal crops and into new pasture, the rest should have grass and some clover drilled in, said Mr Beckingsale. “This seed can be drilled directly into the ground in August or early September when the soil temperature has risen to 6 degrees. This is the temperature where grasses begin to grow, so any

competition will be at a low level. “Hard tips on the coulters of an ordinary drill will do the job and it is important the harrows which cover the seed well, follow the drill. "A suitable fertiliser should be sown with the seed, the type and amount is best determined with a MAFTech soil test. Some nitrogen will help establishment of the young plants. “When overdrilling, two to three kilograms per hectare of white clover should be included with the normal sowing rate of the grasses. “Overdrilling will work well with quick establishing grasses such as ryegrass and prairie grass, while slower establishing grasses such as tall fescue, cocksfoot and lu-

cerne are best established through conventional cultivation or spraying and direct drilling.

“Because seed can now be obtained fairly cheaply, a number of farmers are using prairie grass as a short rotation grass similar to manawa and concord.

“In this role, grazing management of the prairie grass is not as critical as with the longterm stand, but the benefits of winter growth, good hay and silage material, and high lamb growth rates are obtained.

“Overdrilling suits grass grub-damaged pastures better than cultivation, and investment in cultivated low pasture production will have been lost when the grubs were eating.

“With minimum soil

disturbance, overdrilling will allow grass grub diseases to remain in the turf and keep future populations low. Cultivation will destroy those diseases, and leave new pasture vulnerable to another grass grub attack two to three years after sowing.

"Determining the need for pasture rejuvenation at the end of winter can be difficult. If there is a lot of bare ground or flat weeds the answer is obvious, but a critical plant population point when rejuvenation becomes economic, has not been established.

“Pasture rejuventation must compete with fertiliser, fencing and a range of other options to spend any spare dollars on, so the decision is not easy.”