ERADICATION OF WEEDS.

New Zealand Journal of Agriculture, Volume VI, Issue 4, 15 April 1913, Page 403

ERADICATION OF WEEDS.

A. H. Cockayne.

The statement is frequently made that the expense necessary to eradicate weeds is often so . great that it is impracticable to carry out any effective work. This statement is nearly always made in the case of the control of weeds on permanent pasture, where the great factor ,in weed-eradication, good cultivation, cannot be taken advantage of. The problem of the control of weeds on such land is therefore one of considerable importance. Any expenditure, no matter how' great, provided it returns a good interest on the money spent, cannot be looked upon in any. way as a monetary loss to the farmer.. . Unfortunately, too many farmers : destroy weeds merely to keep within the Act rather than as a -necessary procedure in the economy of the .farm.. The work should - never .be regarded as a’ necessary evil, but as an investment capable of giving, an absolutely certain return, often of. very much greater value than the time and money spent’upon it, at the same time giving a permanent and truly increased value to: the property

by reason of the better carrying and selling capacity. It may be well to indicate how much can be actually spent with certainty of profit. On land worth £1 an acre containing 10 per cent, of useless plants an expenditure of over 2s. per acre, will be fully compensated if these useless plants are suppressed and their place taken by utility plants. Thus for every £1 value, of grazing-land containing 10 per cent, of weeds 2s. an acre can be spent with certainty of a profitable investment ; that containing 20 per cent. ss. can be expended; 30 per cent., Bs. 6d. ; 40 per cent., 13s. ; 50 per cent., £1 ; 60 per cent., £1 10s. ; 70 per cent., £2 6s. ; 80 per cent., £5 ; and 90 per cent., £lO. Thus land worth £3B per acre containing 20 per cent, of weeds can have £9 10s. spent on it for weed-suppression, and then show a direct profit,’ to say nothing of the permanent gain. From the above it can be seen that the control of weeds on high-class land will always be profitable, but their control on very cheap land will depend upon the percentage of ground occupied by them. Where this is large weed-control, even if the land be very cheap, is probably payable. Thus, for example, land worth £2 an acre containing 60 per cent, of tauhinu can have £3 per acre spent with profit in controlling this weed.

These remarks refer, very largely to those useless’plants .the presence of which is nearly always condoned by the farmer on the plea that it will not pay to deal with them. Of course, with regard to extremely noxious and aggressive weeds,the. amount that can be spent depends entirely on the loss in the value of the land that would occur were the weeds left in possession.

With the idea of affording country ministers an opportunity of securing some knowledge of farm work and life, the Agricultural College at Missouri (U.S.A.) has established a short summer course for the clergy.

The results of the manurial experiments on the swede crop at the Ruakura Farm of Instruction up to the present, are extremely puzzling, and certainly not what an agricultural chemist would expect, reports the Manager. One of the most even plots and the cheapest as regards cost. of fertilizers received a haphazard mixture of basic slag and basic superphosphate. In every instance where sulphur was added to other manures/ at the rate of 1 cwt. per acre, the germination was excellent, and the plots at the present moment have an exceedingly healthy appearance. •Om the other hand, where sulphur alone was applied to the mangel crop, at the rate of 5 cwt. per acre, the result was not so good as that of the no-manure plot. In the early, late, and subsoil ploughing experiments, which cross the mangel plots, the subsoiling at present shows the best results.. ■ : ■