THE GYROTILLER.

New Zealand Journal of Agriculture, Volume 53, Issue 3, 21 September 1936, Page 166

THE GYROTILLER.

EXPERIENCE IN SOUTH CANTERBURY.

W. C. Stafford,

Instructor in Agriculture, Timaru.

A gyrotiller commenced contracting in South Canterbury in April, 1935, and carried on throughout the winter and spring, working its way up from Waimate County through Levels and Geraldine, and left the district during September, returning again for a short period in October and doing further work in Levels. The itinerary of the machine is mentioned because it has a definite bearing on the results obtained in various parts of the district. The other factor which has brought about diverse results, and in many cases discredited the implement, are the claims made by the owners without having given due regard to the object of the cultivation, the season of the year, the state of the field, and the subsequent crop. The farming community react in only two ways to any new innovation which is destined to interrupt their ordered or usual farming operations. They either treat the innovation with caution and have nothing to do with it until ample proof is available or they adopt the innovation wholeheartedly. In South Canterbury the gyrotiller was adopted immediately. The machine itself commands respect, if only from an engineering aspect ; its depth and width of tillage seemed (and are) admirable for the type of soil in the district, being, as it is, for the most part, clay loam overlying a stiff clay subsoil. These, together with the claims of the owners of the machine, which were that up to 50 per cent, increases had been obtained by the use of the deep tillage due to the opening-up of fresh supplies of plant-food, and also that little or no cultivation was required after the gyrotiller had been used, persuaded the farmer to have contracting done irrespective of the most important matters mentioned in the last part of the preceding paragraph. It was disregard of these matters that has caused any dissatisfaction which exists to-day regarding the work of the implement in South Canterbury. The proof of this lies in the fact that the farther north the machine went from Waimate the stronger the dissatisfaction with the results. As the machine went north, the later in the season was

the cultivation being done, and consequently less and less time elapsed between the cultivation and the sowing of the crop. An extreme case, and one where the dissatisfaction is the worst, is where the land was tilled out of lea in late September with the object of sowing swedes in November. The consequences of such an effort on the subsequent crop are obvious.

It will be assumed rightly from the foregoing that a doubt exists in South Canterbury to-day as to the usefulness of the gyrotiller. Really there is no doubt at all about the efficiency of the implement : used properly, the machine does effective work.

As has been the case with many innovations in agriculture of recent years, over-enthusiasm and lack of attention to the first principles of agriculture have been the cause of discrediting the gyrotiller in some parts. Had. the owners of the machine given due regard to the object of the cultivation, the season of the year, the state of the field, and the desired crop, instead of creating the feeling that the machine overcame all difficulties, the position to-day would not have arisen. Briefly, eagerness not to miss work last season will be a great hindrance to getting work this year in the northern parts of South Canterbury. In the Waimate district, where contracting ' commenced in April, farmers had the work carried out with the object of putting the ground into potatoes, and results have been excellent. There is, however, no reliable way in which comparison of results on gyrotilled and on ordinary

cultivated land can be made. Cultivation in April on lea land with the object of sowing in September-October allows weathering and sweetening to take place, and this. is absolutely essential where such a depth of soil is tilled and aerated for the first time. The weathering reduces the clods, and plenty of time elapses to rot the turf and . make it available for the crop. It was a noticeable fact with the dry spring experienced that the gyrotilled potato crops held out better than others, while it was also said that drainage was better during the heavy rains following. Yields from the tilled land are most encouraging, and will probably average 15 tons an acre. Certified seed was sown in practically all the gyrotilled land, with superphosphate 3 cwt. an acre and sulphate of ammonia 1 cwt. an acre as the manure. Outside the Waimate district the cultivation was carried out mostly with the object of putting the ground into swedes, turnips, and rape. Oats, however, were sown on some tilled land with fair success. Some excellent crops of swedes have been obtained where the work was carried out in early winter. As the machine has worked north and the season progressed,. the results fall away, and some very poor crops are to be seen. It is noticeable, however, that in some cases where a certain amount of cultivation had been done prior to late gyrotilling the resultant crops are quite good, although the crop varies considerably from the sides to the centre of each width of the machine. The cause of this is that the rotary tynes have a tendency to bring up unweathered soil from below to the centre and transfer, all the good soil to the outside edges of each width of the machine. This gives a crop, where the tilling has been done late, an undulating appearance. This feature is not noticeable in the Waimate district. Lessons from the Experience, The lessons to be' learnt from the first year’s working of the gyrotiller in South Canterbury are as follows : (1) Cultivation for any crop on any class of land should be carried out as early as possible. The following is suggested for crops following lea : If tilling is carried out for wheat in January or February, previous top-work can be dispensed with. After these months, tilling should be done only on land that has been skimmed or “ hustled ” earlier. No tilling should be done later than the middle of April. If rain fell on this later tilling it would be impossible to sow the wheat in the winter of that year because the land after tilling lies very open and cannot carry either horses or tractor for some considerable time. For potatoes and oats direct tilling should be done only up to the end of May. After that, tilling should not be done unless the top-work has been carried out earlier.. In this case the tilling should be completed before the end of June. For rape, turnips, and. swedes direct tilling can be done up to the end of July, and after that only on previously worked land up to the end of August. (2) Direct late-tilling for any crop on a lea field has resulted, in the main, in the failure of the crop. This can be attributed (a) The mixing of unweathered soil with the topsoil and consequent temporary sourness ; (b) Lack of consolidation due to the . stirring and opening-up of a considerable depth of soil;

(c) The impossibility of reducing the topsoil to a sufficient tilth for a suitable seed-bed after tillingdue to the fact that as there is such a quantity of loose soil the lumps run in and out of the tines of the implements doing the top-work without causing . any pulverization. To ensure a successful after-crop it is advisable to gyrotill early to allow the top to sweeten and consolidate, and then to cultivate the top 4 in. -5 in. into a sufficient seed-bed for the reception of the particular crop desired, remembering that gyrotilling does not do away with the necessity of manuring the crop on the approved lines. The effect of the deep cultivation in subsequent years has still to be observed. It seems, however, that it should be of great benefit in freeing the stiff clay of the South Canterbury Downs, resulting in better drainage and easier root-development of the plant. On land infested with the more difficult twitches, such as creeping-fog and couch, yarrow, and other underground creeping plants, gyrotilling should not be done unless an absolute bare fallow is to be carried out for the following six or eight months. The action of the tillers mixes to a considerable depth much of the top turf, thus preventing the eradication of the rhizomes. On such land cleaning on the usual approved lines should take place before tilling. Gyrotilling should not take place on land to be sown into grass that season. Lack of consolidation will result in a failure of the grass to establish. One of the most useful features of the implement is the manner in which it can successfully deal with the corners of fields, neglected fence-lines, and isolated areas infested with gorse, blackberry, or broom of almost any height. It can till such places considerably more cheaply and more effectively than they can be cleared and ploughed by the usual methods. Relation between Gyrotilling Contract Work and the Cost of Crop Production on the Farm. It can be definitely stated that gyrotilling at the correct time increases the cost of production of the subsequent crop. The operation purely from a tillage viewpoint only does away with the usual ploughing operations is, skimming and deep-ploughing the amount of top-work that has to be done after either method to procure a suitable seed-bed being approximately the same. Thus, allowing for skimming and cross-ploughing at Bs. 6d. per acre and deep-ploughing at 10s., the cost of production is increased as by gyrotilling £2 10s., less cost of ploughing operations £i 75.: increased cost of production equals £1 3s. per acre. As to whether this increased cost of production per acre is offset by an increased yield sufficient to lower the cost of production per unit, whether it be a bushel of wheat, oats, &c., or a ton of potatoes or roots, is at present not known, as there is no reliable information available on the subject.

However, considering the class of work done, it would be unreasonable to charge the immediate subsequent crop with the whole cost of the gyrotilling operation. The work performed is of such a nature that its beneficial effects are likely to be felt for many years after the work has been done. A parallel case would be the effect of lime.