Lucerne Worthy Of Its Place In Central Otago

New Zealand Journal of Agriculture, Volume 63, Issue 2, 15 August 1941, Page 99

Lucerne Worthy Of Its Place In Central Otago

By

W. R. LOBB,

Instructor in Agriculture, Dunedin. "

ALTHOUGH the importance, of lucerne throughout Central Otago lucerne throughout Central Otago is becoming better known each year, it has been slow to gain the recognition it deserves, and at the . present time there are many districts in which lucerne is deserving of a much wider

use. Its extension is, however, gradually going on, and today the tendency is to sow very much larger areas per farm to 70 and 80 —instead of the small hay paddock which was the vogue in the early days of lucerne growing. The value of this changed outlook cannot be too greatly stressed for many areas in Central Otago. ■, Some of the factors responsible for this changed outlook are:— (1) The realisation that the grazing of lucerne is profitable. 1 (2) There is much more certainty in obtaining a satisfactory strike since the introduction of inoculation. 1 (3) The use of lime. (4) The study of soil conditions. (5) Increased costs of growing root crops and their uncertainty. (6) Power machinery for handling crops. (7) A genuine desire for better winter feeding. The last-mentioned factor has had a very large influence, and is possibly the greatest single factor for the increase of ‘ lucerne in areas where it has already proved its worth, and also in taking lucerne further afield. The instance can be quoted of the establishment of lucerne on the Styx Plain, which is 1800 ft above sea level. Here the winter is long and the conditions very severe, and the, average winter feeding , for flocks of approximately 2000 sheep has in the past required the cultivation of more than 200 acres of land each year. It is natural, there-

fore, that some plant would be looked upon to fill part of this winter feed requirement. It is this factor which has brought about 'the successful establishment of lucerne there.

• . . Soil Conditions

A study of soil conditions and a realisation of the part these conditions

play in , the growth of the plant and on soil organisms has been an important factor .in successfully establishing some lucerne stands. In one case, for example, it was found that very little could be established on some of the alkali soils in low-rainfall areas. Where the conditions have not been too extreme, it has . been found possible to obtain lucerne stands by sowing after heavy rain. Once the lucerne is well established and, the roots . have penetrated beyond the alkali the stand should flourish. Here, again, irrigation has J played an important part. Surface irrigation of lucerne tends to weaken a stand and, if : continued, will in time result

in the complete disappearance of the lucerne in favour of grasses which utilise more surface water for their shallow root system. This applies to some conditions only, and the case of irrigating young lucerne on alkali patches is, for , instance, an exception. The water tends to remove the salts from the sphere of activity of the roots while' the young plants are establishing, and stands have been obtained in this way where it has been impossible to obtain them previously.

A further point in obtaining good strikes . after a study of soil conditions is found in the application of lime to sour soils, - where previously strikes have been poor and stands have ultimately failed, due to their inability to compete with grasses and weeds which have found the conditions more to their liking. On the whole, the lucerne country in Central Otago is “sweet,” but there are exceptions. Where these are. being studied, lucerne is being successfully grown where previously, it has been condemned.

Use of Culture

Very few attempts are made to establish lucerne without the use of the bacterial culture,. This practice is so well established as to need little comment, but one must not look upon the value of the culture from the sole standpoint of assuring a strike. The accompanying illustration shows the results of . inoculation . after four

years. On the right is a fairly dense healthy sward which received the culture when established. On the left is a strip at the end of the paddock sown without culture. The effects of the culture were noticeable immediately, but it has become more outstanding each successive year, until now, after the fourth year, parts of , the noninoculated stand have given way completely to the competing grasses and

weeds. The lucerne plants on the left are becoming choked by grasses and weeds, and are producing only a small percentage of the bulk produced by the plants on the clean stand.

Lucerne as a Winter Feed

Many farmers now realise that lucerne can be successfully grazed and is providing an essential link in the food supply of ewes and lambs. The number of early lambs obtained from ewes running on lucerne is increasing each year, with the result that more and more stands are being used for this purpose. Lucerne is also coming into its own for fattening store lambs and old ewes, although later in the season lambs do not flourish as well or put on weight as quickly as they do on rape.. The uncertainty of the rape crop in many districts, however, mitigates against its use, and it is well that lucerne can be relied upon to take its place. . . It should not be taken for granted, however, that lucerne can be haphazardly grazed—indeed, there are many questions involved, not only on the animal side, but also from the

point of view of the plant. For instance. lucerne on heavy, rich soils will not stand as hard grazing as will that on light soils. Grasses, clovers, and weeds will encroach on good soils, and will compete to the disadvantage of lucerne under hard grazing conditions. There are many light soils in Central Otago which will grow very little else but lucerne. In such cases lucerne has been grazed “as bare as the road” and made great recoveries. Such stands' will maintain themselves for years because there is little competition from other species. Under competition, lucerne is not generally killed out through the grazing animal, but more often because it is placed at a disadvantage with other plants, either because they are not palatable and are therefore not grazed, are quicker recovering after grazing, will stand more tramping, or will stand closer grazing.

Rates of Seeding

The rates of seeding have an important bearing on the results. Although excellent stands of lucerne have resulted from the drilling of less than 51b. of seed to the acre, there is no doubt that the lack of competition factor has played a significant part. A low seeding will give results if conditions are right and if the competition from other plants is negligible, but there are very few conditions which would warrant the risk of sowing as little as 51b. to the. acre. In some cases where the soil is heavy and the weed invasion (both of annuals and perennials) is likely to be severe, 181 b. to the acre may not be considered too much. Here, again, the farmer who studies his soil conditions, : his cultivation, and his previous results can form a sound, opinion .on. what is likely to be the result of sowing too small a quantity of seed, and can guard against doing so. .. . : The value of lucerne as a hay crop has been proved, and it is well utilised today.' Under good conditions, lucerne will give four and sometimes five cuts in the season, and has yielded nearly ten tons of hay to the acre in Central Otago. In dry conditions, if a stand of lucerne had a life of only five years under grazing, it would still be ahead of anything yet known in giving results on much of Central Otago’s grazing lands. "V-