BARE FALLOWS.

Otago Witness, Issue 1834, 14 January 1887, Page 6

BARE FALLOWS.

Of late years a variety of circumstances — mostly resulting from previous indifferent cultivation and continuous cropping — have compelled farmers to adopt the practice of summer fallowing, and this season there is 'a considerable extension of the area usually reserved for the purpose. It is a case of necessity, not ©f choice for had these fallowed lands been in moderately fair condition, and not overrun with weeds, undoubtedly another general attempt would have been made to crop them. Experience has, however, taughtcultivatorsthatcropping foul and impoverished soils results in a " maximum expenditure and minimum yield," and further, that putting such under grass is merely a wasteful expenditure in grass seeds. The only alternative is, therefore, the bare fallow, for though on soils of medium quality, even if foul, a fair crop of roots may be raised in drill and the land cleaned at the same time the expense is considerable, whereas on dirty and exhausted soils the capital required for renovation by liberal applications of manure and costly cultivation places the course beyond the means of ordinary farmers in these times. In such cases improvement and clearing of weeds must be proceeded with economically and by degrees, and thorough summer fallowing will prove the cheapest and most effectual preliminary process. Fallowing, however, as commonly practised falls far short of effecting the desired object. The land is ploughed, and during the summer harrowed once or twice to kill weeds as they develop their growth. The necessary cultivation is considered to be complete by a preparatory ploughing for the crop to follow, and ordinarily this first one is a success, bub the benefit is only temporary, the weeds have been scotched, not killed, and the one crop is sufficient to exhaust the small store of plant food which accumulated during the period of rest. On old cultivations weeds have been struggling with corn crops for years. Their seeds matured, shed, and were annually ploughed in until the whole of the disturbed soil is permeated with them. Quantities remain dormant because at some depth from the surface, but ready to burst forth into vigorous growth when turned up by the plough, and again the supply is replenished if the fresh growth be permitted to seed. A capital illustration of the inefiicacy of insufficient cultivation may be seen on a property distant only a few miles from Dunedin. A paddock which had been for some years cropped for grain or oaten hay was ploughed with the object of fallowing in the spring of 1885. It was once scarified during the summer, which was exceedingly dry, and therefore afforded an excellent opportunity, ' had it been availed of, of killing both roots and seeds of weeds by repeated disturbance. In the autumn the land was again ploughed, and this spring costly grass and clover seeds were sown. At the present time there is a very level struggle between weeds and grasses. The scarifying and consequent disturbance and exposure of the seeds and roots to the heat and drought killed everything on or near the surface, but there was an underlayer untouched, with an ample store in reserve, and which was brought up by the subsequent ploughing. The grasses will be but a partial success, and in a year or two the land will be as foul as before. . To effectually eradicate weeds by fallowing necessitates ' the repeated disturbance of the soil. The seeds must 1 be induced to germinate, and roots and rootlets must be " teased " to death. Conon, thifitles, and docks mast of course be

forked and hand-picked, but most of other kinds may be killed by repeated ploughing, harrowing, and scarifying, the expense of which js r but .a. fractional part 1 of what it years' ago, provided ..suitable implements be used.- '-The question regarding the destruction of weedjS by the most effectual and least costly means is' one j of vital importance to farmers, for within the past three years couch -and. sorrel especially, with other obnoxious vegetation, have taken such a hold in whole districts that, until eradicated, the occupation of the infested land must prove unprofitable. It is* therefore that the area fallowed this season has been so largely increased, and as. operations must prove; more 1 effectual during the' hot, dry weather j be'tweetf 1 the present time and harvest, and horses can be conveniently spared, the fallows should be thoroughly .worked. •- It must 1 be" remembered that however necessary the eradication of weeds may be, other substantial advantages accrue from a well-cultivated fallow. Liebig, 'in'his work on " Modern Agriculture," points out that " as the smallest portions of plant food cannot of themselves leave the spot in which they are held firmly fixed by the soil, we can understand what immense influence must be exerted on its fertility by its careful mechanical division and intermixture. This is the greatest of all the difficulties which the agriculturist has to overcome." And, further, the thorough comminution, intermixture, and aeration of the soil stimulates chemical action, fresh combinations of its constituents, and enlarged supplies of plant food.

From time to time we have endeavoured to impress on farmers the immense benefits which they would derive from a judicious deepening of the soil. Two objections only have been urged •gainst the proposition— one the old bugbear, the fear of the subsoil ; the other the cost of tb'e work. Now we have never counselled the immediate admixture of the unaerated s"ubsoil with the loose, pliable surface, but our contention < was, aud is,' that by merely breaking up the subsoil so that the air may have free access to it, a new source of plant food would be gradually made available, tor science teaches that in, the great majority of soil the earth at varying depths contains fertilising constituents which only require amelioration by exposure to atmospheric influence to render them suitable for the nutrition of plants. The breaking up of the subsoil has been reduced to a minimum since the introduction of double and treble furrow ploughs. In South Australia the latter are much used for this purpose, aud tines or subsoilers follow each breast. A second ploughing with tines properly attached to the implements could now be given to the fallow at a cheap cost while work is slack, and most unquestionably with permanently profitable results.