The Grassing of Peat Swamps.

New Zealand Journal of Agriculture, Volume 57, Issue 6, 20 December 1938, Page 482

The Grassing of Peat Swamps.

Stumping and Peat-burning Methods.

G. S. Robinson,

Instructor in Agriculture, Palmerston North

THE breaking-in of peat swamps has always been a task requiring very careful .consideration.' . In the first place, drainage is absolutely necessary, but, together with drainage, consolidation must go hand in hand. Drained peat swamps are generally characterized by their looseness, which must be guarded against if moisture is to be retained as much as possible ■ in the surface soil. Consolidation is the only feasible method of doing this during the gradual course of the drainage. ’ ‘ ' It is, however, impossible, no matter how much care is taken, to avoid a slightly overdrained state, and this means that during much of the year the soil is loose and dry. In certain circumstances, farmers have found it advisable in grassing peaty soils to burn the peat to a definite level and to avoid the. over-drained ■ state by bringing the surface nearer the watertable. - .

The Pasture Carried.

In the raw state the stump-studded country is used for rough cattle-grazing, and carries a pasture of which the main constituent ,is tall fescue. The soil consists of a loose, organic section of peat of 12 in. to 30 in. in depth overlying river silt of good water-holding capacity and of high fertility. It is not, therefore, an area of deep peat.

Two methods are at present being used in an attempt to bring this into first-class pasture. The first method consists in stumping, ploughing, cultivation, and sowing down, which averages out at a cost of from £2O to £25 an acre. . Consolidation is the main requirement in obtaining a good .strike of grasses and clovers, and the rolling of the cultivated land six or seven times with a heavy roller as illustrated in Fig. 2 is essential. Even then, the soil is loose and pasture establishment is difficult. In Fig. 3 the establishment of rye-grass and white clover sown in March, 1938, has not been good, even though every

effort was made to secure adequate consolidation, and the pasture has carried very little stock during the winter. Costs would prohibit a farmer breaking in a large area of his farm in this way.

Another Method.

Another method is being practised namely, that of burning off the peaty section of the soil and sowing the grassseed on the ash. A trench is made around the area to be burnt in order to confine the burn. This necessitates going down about 15 in. to 30 in. to the silty layer. In Fig. 5 this trench is illustrated after the area was burnt. This method is much cheaper, : but because the stumps are left it can be regarded as a more temporary method of breaking in the swamp. The only costs are those of the seed and of the clearing-away of the smaller stumps, which, on the average, amounts to about £5 or £6 per acre, but depends on the extent of stumping. . Consolidation of the . ash is obtained by dragging four railway-irons, bolted together in the form of a square, over the ash. Figure 7 illustrates an area sown on burnt country within a few days of the sowing of the pasture in Fig. 3. The former mixture contained more temporary rye-grass, which would naturally give greater growth in the early stages, but,

nevertheless, as the photos show, there is no comparison between the two. In July this area of 17 acres carried 270 wethers for three weeks, the sheep showing remarkable improvement while on the young grass.

Less Expensive.

This method, in addition to being less expensive in bringing the farm into firstclass pastures, appears to have advantages lasting several years at least. Frequently, where grass is sown on the peat, rye-grass gradually goes out, giving place to weeds and poorer species, including tall fescue. After several years, too,

the land settles in parts and becomes very rough. The pastures on burnt areas grow excellent white clover, especially in the first year or two, tending, in fact, to choke out . the rye-grass where careful grazing management is not practised. The country mentioned in this article, when stumped and ploughed but not burnt, is excellent cropping country, exceptional crops of potatoes and onions being grown. Thus, the burning of the whole farm; would not be advisable. Certain areas could be kept with profit with a view to using them for cropping. * ■> <■

1 11 11 1 1 1 1 1111 111111111 011 l | Two methods are - at I | present being used to I I bring stump - studded j i country into first-class | j pasture. These methods I | are examined in this | | article, and consist of I | (1) stumping, ploughing, | | cultivation, and sowing, and | | (2) burning off the peaty | I section of the soil and | I sowing the grass - seed on | I the ash. | I - ■ .. . . \ ■ • • I num t; .:ni.::iim run iimmdr;