Department’s Major War Against Nassella

Press, Volume CI, Issue 29798, 14 April 1962, Page 6

Department’s Major War Against Nassella

Less than two months has elapsed since the Lands and Survey Department began taking over North Canterbury hill country properties on which nassella tussock infestations were beyond the control of the landowners, but already the giant task of control and rehabilitation is well under way.

With the tractor and the aeroplane, a full-scale attack is being made on the tussock; using knowledge and experience gained over recent years on experimental plots and in the field by Department of Agriculture scientists, the North Canterbury Nassella Tussock Board, and the department’s own field officers.

A visit made this week to part of the Waipara area showed the scheme under way and gave some indication of the magnitude of the task which faces the department before the tussock is eventually brought under control, the land rehabilitated and available again for private settlement. Bulldozing, tractor cultivation and seeding, aerial spraying, topdressing and oversowing, hand grubbing and spraying are ail finding their place.

To date the department has taken over 15,634 acres. Three Waipara propeities totalling 2384 acres have been grouped to form the Wash creek settlement block, 5960 acres of Teviotdale form the Tirimoana block, 3728 acres is at Mount Parnassus, and 3562 acres at Motunau will be known as the Glencoe block.

From these properties the department has taken over about 7200 sheep and between 350 and 400 head of cattle. This stock will be worked and transferred from block to block according to feed availability and the policy of stock management in relation to the primary aim of bringing the tussock under control.

The department wasted no time in getting to work. The first property was taken over on February 20 and the tractors moved in and started work on March 6. “Kill” spraying was begun earlier and this was started in the first week of February Fixed-wing aircraft were used to apply 401 b of 2,2 D (the new designation for dalapon, basfapon and gramavin) in 20 gallons of water to the acre to give thorough wetting. As 2,2 D gives the best results applied in January and February the aim was to get as much spraying as possible done before the end of February, but the spraying programme had to be halted because practically all the available stocks of the herbicide in the country had been exhausted. More has been imported and the department is holding 40,0001 b of 2,2 D in readiness for spraying next year.

More will probably be required as, with Tirimoana included. the spraying programme next year is likely to involve between 2000 and 3000 acres of non-arable hill country and gullies. On the unsprayed areas which can be cultivated the four tractors are working every available hour of daylight, with Sundays set aside fpr maintenance.

About 300 acres has been cultivated and sown down into pasture, using a mixture of a bushel of perennial ryegrass. half a bushel of short rotation ryegrass, and 31b of Montgomery red clover, together with two hundredweight of superphosphate. Of the 300 acres sown with the pasture mixture, about 100 acres has been sown also

with a bushel of Cape Barley to the acre, 100 acres with half a lb of turnips and the half a pound of turnips and the balance with threequarters of a bushel of lupins. Before the cultivation work the area is marked off and firebreaks are bulldozed to prevent the gullies being burned. The tussocks are burnt off to ground level and the first tractor makes a double cut with the ‘‘bush and bog” discs. This breaks up the ground well and it is then chisel ploughed and harrowed with the second tractor.

After rolling, the land is seeded with the disc drill, used because it is more stable on the hill sides and because it gives a bit more cultivation, and harrowed. It is then rolled to consolidate the ground to to conserve moisture.

Establishing pasture cover on this area will not be as easy as on the department’s Glenbourn.e property at Waiau, where the technique has been used with success Tile Waipara hills are drier and more subject to northwest winds. This will make Stock management in light grazing of critical importance if the cover is to be preserved.

The department expects the pasture will last for about two years before nassella seedling regrowth makes it necessary to work the ground up again and resow it. However, the second cultivation will be easier and much cheaper without the dense mat of old tussock roots and stumps, and the second pasture should last longer. Some of the sprayed areas which were thought to be too steep for cultivation are being worked up as well Bulldozing is being used to level uneven faces to enable them to be cultivated and drilled into pasture.

More than 100 hours has been worked with the bulldozer, making firebreaks.

tracks, levelling faces and filling in under-runners. The inaccessible gullies and roadsides have all been

“kill”-sprayed and these will be oversown. They will not be grazed, and the sowing will be solely to establish competitive cover to suppress the nassella regrowth. Although the topography is rugged and broken a very good coverage was achieved by the aircraft.

The cost of this control programme is no small item. Spraying with 401 b of 2,2 D has cost £l3 10s an acre, a figure slightly less than an individual farmer would pay, as the herbicide is bought in bulk under Government contract.

Towards the end of this month the department will begin its aerial topdressing and oversowing of the ■‘kill”-sprayed areas. Sixty tons of fortified superphosphate will be applied at two hundredweight to the acre, together with a mixture of 51b of perennial ryegrass, 41b of cocksfoot, 21b of phalaris. 31b of white clover, 31b of red clover, and 31b of subterranean clover. A further 600 acres of fairly clean hill country in the Wash creek settlement block will be topdressed from the air with one hundredweight of fortified superphosphate. This area has been worked over by grubbing gangs of the North Canterbury Nassella Tussock Board to remove the scattered tussock in readiness for the topdressing. 1 Some idea of the class of country being worked can be gained from the photograph of the four tractors on this page. They are on top of a fairly level ridge with a steeper slope behind them. In the left background the burned-over slope can be cultivated, the centre background has been bulldozed to enable further working but the part of the slope in the right background is too steep and has been “kill”sprayed. This will be topdressed and oversown.