Establishment of Paspalum: Lupin Varieties

New Zealand Journal of Agriculture, Volume 79, Issue 6, 15 December 1949, Page 561

Establishment of Paspalum: Lupin Varieties

SEASONAL NOTES Contributed by the EXTENSION DIVISION

ON moist soils in the warm northern districts of New Zealand paspalum is a valuable producer of summer and autumn feed. If paspalum is combined with perennial ryegrass and white clover and the sward maintained in that condition by controlled grazing and adequate manuring, the grass can make a valuable contribution to summer dairy production without loss of production in winter and spring when paspalum is dormant. On the other hand, pure swards of paspalum have a very low winter and spring production and, except on the very richest land, soon become sod bound if neither white or subterranean clovers nor Lotus major is an important constituent of the pasture.

PASPALUM belongs to a group of plants most of which are natives of tropical or semi-tropical climates. Therefore it will thrive only in a district having a warm summer and a fairly high annual rainfall. Nor will it stand severe winter frosts, so its use is confined largely to the warmer areas of Auckland, Poverty Bay, Hawkes Bay, and Taranaki Provinces. Though paspalum is a most vigorous summer and autumn producer when properly managed, it is not an easy species to get established in the normal autumn-sown pasture mixture. The seed varies considerably in germination, much of it being very poor, particularly New Zealandsaved seed, and consequently farmers are advised to sow the better-germinating Australian seed. In all cases they should insist on being supplied with seed of a satisfactory standard of germination. Slowness of Germination Paspalum seed is rather slow to germinate, and the young seedlings require warm soil conditions if they are to come away quickly. They are very susceptible to frost injury and are easily smothered by more rapidly-growing species in the mixture. Because of these factors, many farmers have had disappointing results from paspalum sown in autumn, frequently having to wait several years before much of this grass is seen. Experiments at Warkworth, Northland, in which paspalum was autumn sown in a mixture containing ryegrass seed showed little or no paspalum until the second spring afterward. In this trial it was evident that the establishment of the paspalum was greatly affected by the quantity of ryegrass seed sown — greater the quantity of ryegrass, the poorer was the establishment of paspalum. This experimental evidence was confirmed in a similar trial at Taumarunui. At first glance the obvious solution would appear to be to sow down the pasture mixture in spring rather than in autumn, but certain factors limit the success of this practice. In most districts spring sowing is done in September or early October, when annual weeds are starting to appear. In districts subject to heavy annual weed infestation the success of a spring-sown pasture is jeopardised by weeds, the growth of which frequently is so heavy as to smother out many of the pasture species. Again, if ryegrass is included in the mixture in any quantity, it will create the same smothering effect as it does when sown in autumn. Trials with New Methods Of recent years several new methods of establishing paspalum have been tried with very encouraging results. These are all based on the knowledge that paspalum seed requires a warm, moist seed-bed for satisfactory germination and that the seedlings cannot stand heavy competition from associated species. The first of these methods is to sow paspalum seed pure in November or early December, following it with the

balance of the pasture-seed mixture in the next autumn as an oversowing. Paspalum is sown on a well-worked seed-bed at the rate of 6 to 81b. per acre. The seedlings have excellent conditions for germination and ample room to develop. This method has given good results in several cases, but an improvement would be the inclusion of 3 to 41b. of red clover seed with the paspalum seed. The clover gives some protection to the young paspalum as well as providing nitrogen for the seedlings. On soils especially suited to red clover excellent grazing can be obtained from the area in late summer and early autumn, and conditions are ideal for surface working the ground in late February or early March before the balance of the seed mixture is sown. ' Another method tried with success is to sow paspalum and red clover with seed for a swede crop. By the time the swedes are properly in leaf the paspalum is well established and with the red clover provides a valuable supplement to the swedes in the following winter. After . the swedes have been fed off the paddock is grazed in the normal farm grazing programme and provides good feed in the following late summer and early autumn, after which it is renovated with the balance of the pasture mixture. Excellent results have also followed the sowing of paspalum with soft turnips or rape. If the seed is sown early, or if the resultant crop is to be fed off before March, the balance of the grass and clover species may be autumn sown. . On an established farm on which paspalum is already present in some of the paddocks this grass will soon show up over the whole area and its establishment and spread offer little difficulty, but on the farm where there is little or no paspalum the methods of establishing this grass described can be of value. In cases where they , have been tried farmers have found that strong, healthy paspalum is present within 3 months of the seed being sown. The introduction .of paspalum into an all-grass farm which contains none of this ■ species, and on which no ploughing is to be done, presents another problem. Attempts to oversow pastures with paspalum have not been very

SEASONAL NOTES . . .

satisfactory because of the slow germination and rate of establishment of the paspalum seed. Many farmers have had fairly good results from feeding out paspalum hay, but obtaining a good-quality hay containing a reasonable quantity of viable seed is the difficulty.

LUPINS are a valuable fodder crop, *J* "’T* ’ especially on light and medium , ’ • < . soils where prospects of obtaining a good turnip crop are uncertain. They S' WfF 1 " are a safe crop under average farm * 5 management and provide a fair amount [ t ., »W 7; 1 - of feed of high nutritive value. They j can be fed to stock at any stage of * growth, but usually are left until near \ Hi jrPjiffl? *'i flowering. At this stage they provide §4 s ; the maximum of leafage with a mini- t* mum of coarse stem. Until then they l‘z 2 are resistant to heavy frosts, but once £ the buds begin to show colour this frost W resistance disappears and plants are likely to be damaged by lighter frosts Sheep gr than they may have withstood already. Though lupins sometimes suffer from attacks of “sore shin” and sclerotinia disease, the damage is seldom extensive. They appear to be highly resistant to insect attack, a characteristic that makes them all the more valuable in areas where turnip crops are uncertain. They are also excellent for introducing nitrogen into the soil and are valuable as green manure.

At present two varieties, Bitter Blue and Sweet Blue, are in general cultivation and fill a valuable place in the farm economy where they are being grown. A Sweet Yellow variety has also been tried. Bitter Blue is the variety introduced to Canterbury more than 20 years ago. It is a strong-growing plant and pro-

vides a fair amount of nutritious feed. It has taken the place of turnip crops in districts where turnips cannot be relied on. Bitter Blue lupins are not grown as a fattening crop, but rather as a crop that will provide a succulent bite when other feed is short. Though occasionally used for feed in spring, they are more popular for grazing in autumn and early winter. They are extremely bitter and sheep need to be introduced to them gradually. Ewes soon acquire a taste for the plants despite their bitterness. Once acquired, this taste does not appear ever to be forgotten, and sheep will then eat them readily at all times.

Sweet Blue variety is very similar to the Bitter Blue in appearance, but it has a low alkaloid content and lacks the bitterness. Sweet Blue lupins can be used for autumn and winter feed, but

their chief advantage is their payability and therefore their usefulness for lamb fattening. They appear to be more delicate than the bitter variety and require a slightly-better soil and a higher rainfall to produce the maximum results. Their palatability brings the disadvantage that hares will travel long distances to eat them in the young, succulent stage and have been known to clean up small areas completely. They are well worth a trial in areas where rape is likely to be damaged severely by diamond-backed moths, white butterfly, or club root.

Sweet Yellow lupins for good results appear to need warmer temperatures and are more suitable for North Island conditions than the blue varieties. Trials in the north have compared Sweet Yellow lupins with both Sweet Blue lupins and rape for lamb fattening. Results have been encouraging, particularly on the sand country of the Manawatu district, but scarcity of seed supplies has prevented a wider use of this variety. The seed shatters from the pod very easily, so that much is lost during harvest, and seed yields have been very discouraging. This variety has been grown in Canterbury, but has not proved very successful. Trials are now in progress with a nonshattering type of Sweet Yellow lupin which, if successful, probably will solve the seed-supply problem.