Development of Swamp-land in Waituna District, Southland

New Zealand Journal of Agriculture, Volume 89, Issue 4, 15 October 1954, Page 329

Development of Swamp-land in Waituna District, Southland

By

W. FAITHFUL,

Fields Instructor, Department of Agriculture, Invercargill

APPROXIMATELY 3000 acres of swamp-land is being developed by the Department of Lands and Survey in the Waituna district, Southland. Included in this development block is some of the most difficult land to improve, consisting of part of a very extensive area of swamp, known as the Seaward Moss, estimated at about 80,000 acres. This swamp area can be broadly divided into 3 main classes of land: First, a very wet, spongy peaty complex about 4ft. deep resting on a marine gravel, the cover being dominantly moss and manuka. Next is a raw peat up to 15ft. deep which is confined generally to the watersheds and is carrying manuka up to 14ft. high. {These two types constitute the major part of the Seaward Moss area.) The third type is of only limited area and comprises a very wet clay soil growing red tussock, flax, moss, and some manuka.

THE 3000 acres at Waituna has been taken over to investigate the possibilities of more extensive development of this type of country. Isolated blocks of land throughout Seaward Moss have been and are still being developed by individuals, but these blocks are more or less confined to the wet clay land types and to the margins of the peat complex soils. The method of development employed has been the excavating of main drains and such other drains as may be necessary before any cultivation work could be attempted. As soon as the area has dried out sufficiently to carry the tractor the land is swamp ploughed, and after being left to weather during winter is worked in the following spring and sown in ridged turnips. The turnips are grazed off during winter and a second turnip crop may be grown, depending on the state of the block.

The following year a permanent grass seed mixture is sown. Alternatively, oats and grass may be sown in the second year and the resultant pasture left down for 2 years. This temporary pasture is then ploughed, a crop of turnips taken, and then the area is sown out in permanent pasture.

During the development the land is given 1 ton of lime each year until 3 tons per acre has been applied, and the pasture paddocks are topdressed with 2jcwt. of phosphatic fertiliser and i ton of carbonate of lime per acre per annum. The development of this land has been assisted very materially by preliminary drainage work carried out by the Southland Catchment Board. Some of the developed country is of high carrying capacity. An area adjoining the Waituna Development Block, which was capable of carrying only a few cows on 1100 acres in 1932, is now carrying 800 ewes, 300 dry sheep, and 60 cattle. Development began in 1937, but the major development has been done during the past 6 years (since the Catchment Board drainage was completed) and there are now 250 acres of sown pasture and a further 100 acres in the course of development this year. The grassing of the Department of Lands and Survey area will be along the lines successfully employed in the development of peat swamp in the North Island, with modifications being made as they are required to meet local conditions. After excavation of the initial main drains mole drainage is being done with a specially made mole plough to deal with this swampy land, parts of which are full of timber and roots. Surface cultivation with a heavy rotary hoe and a heavy roller is then undertaken and a pasture mixture sown without any preliminary turnip crops being grown; an experimental sowing has already been made on about 55 acres.

Free Bulletins on Farm Management Nos. 255 The Farm Tractor. 265 Erecting a Seven-wire Fence. 271 Farm Shelter. 286 Farm Drainage. 344 Farm Water Supplies. 346 Homestead Shelter Planting. The above bulletins, part of a series of over 350 on all aspects of farming, are available post free from the nearest office of the Department of Agriculture, or from the Head Office of the Department, Box 2298, Wellington.