THE FARMER.

Otaki Mail, Volume 26, 13 August 1919, Page 4

THE FARMER.

SEAWEED AS A MANURE. It is an odd fact that, although wo are an island people, largely dependent upon imported fertilisers and are at the moment menaced by the high coat of plant foods of every description, we do not make fuller use of seaweed. Our coasts, estuaries, and tidal rivers yield vast quantities of thin weed. Its valaa us a fertiliser is indisputable, yet it is only in comparatively limited areas that practical use is made of it by land cultivators. Many potato growers in the west -of Scotland, the farmers and

gardeners of the sea margins of the south-western English counties, and the intensive cultivators of the Channel Islands to a great extent rely upon this driftwood for the fertilisation "of the bulk of their crops. But, with these exceptions, ii may safely be said that over the whole of the remainder of the country the use of seaweed us manure is non-existent.

To most of us seaweed is doubless .uiavailablc on account of the cost of fathering, haulage, and transit; but to the many who live within reach of "he chore, to those whose lands might

be served by the long arms of navigable rivers and canals, no such excuse

t,i be offered for neglecting this

beautiful source of manure and revenue. I have an instanco in mind of a large market grower of potatoes, greens, and 'other vegetables, whose land was situated some miles from tho sea, but adjacent to a tidal river. This man employed sea fishermen to cut the weed, and they towed it up the river, whence it was carried to the land. The soil being light, tho seaweed made an enormous difference to the crops. Whilst this grower was producing 16 tons of potatoes to tho acre, his neighbours were only- lifting o' tons! Yet the latter, though they had lived by the river for generations, had never dreamed of using the weed which thuy could get for the gathcriug. Tho chief elements' of valuo in seaweed, from our point of view, are nitrogen and potash. It is as rich in the former as farmyard manure, and when decayed in the soil these ammonia compound* very soon become available. There is more potash in seaweed than in an average sample of farmyard manure, but it is very deficient in phosphates; bonce the wisdom of using superphosphate along with tho weed — a combination that has been proved by extensive experiments in many quaricrs to give better returns than that of super and dung. Potatoes, as I have suggested, respond readily to dressings

of seaweed, and it is invaluable for all l.rassicac, mangolds, and other hungrj crops, especially on thin, porous land. On such soil the weed also has n mechanical value in conserving the moisture during hot weather, the salt it contains often being of marked bcue!i! hi keeping the ground cool. Seaweed, however, affords no humus, heing converted by decomposition into soluble substances. The best practice,

therefore, is to plough it in whilst still fresh —in spring, if possible —and not lo leave it in heaps exposed to the wea.;,,.,.—;l process which robs it of the greater part of its fertilising element*. On the other hand, it mar be mixed

with strawy manure, peat moss, vegetable rubbish, road or ditch cleanings, and such-like material. These, in rotting (a proccia much accelerated by the weed), will absorb the useful properties of the seaweed, and hold them uutil such time as tho compost can be railed on to the laud. If stacking of the weed alone, must be resorted to. fresh wet samples should be used, and the heap so built that it will throw.off must of the rain. In districts where seaweed is regularly employed and plentiful, as much as -10 to 50 tons an acre is used for potatoes, mangolds and other vegetables, but considerably less than that for coin. Guano is frequently applied as a supplementary fertiliser instead of superphosphate, but the latter appears to be the more reliable on most land, and to give higher results. There is usually a marked absence of weeds on land freely dressed with seaweed. This is doubtless owing to the fact that the alkalies of the material are obnoxious to many inland weeds, and thea there are. of course, no seeds of these pests, no spores of fungoid diseases in seaweed, as is so often the ease with {'arm manure.

Seaweed varies widely in manurial value, the thick, strap-like Laminaria being the richest in plant foods. This. however, takes longer to rot. and for ajost practical purposes the common blacK Fucus of the rocks and tidal margins is as useful as any, springgathered samples in all cases being the best. So far 1 have pome across no reports of acidity, fungoid growth, or ether objectionable features arising from the use of this material, even on clay land, and there are few. if any. crops with which seaweed does not agree. In addition to the vegetables mentioned, it is especially good for carrots, celery, and parsnips, and is

most serviceable, mixed with littery manure, as a summer mulch for any

anion crop, including fruit trees. — Agricultural Gazette."