- Spineless cactus
|Last update: April 10, 2012 02:17:24 PM|
F. H. Bosman
THE effects of drought to be seen over a wide part of the Union at present again serves to emphasise the need for the production of, drought resistant fodders and feed reserves. As such, spineless cactus has a wide use.
Because of its high water content it is not of high feeding value and being low in protein content it does not approximate a balanced ration, but it does provide heavy yields .of succulent feed which is invaluable in times of scarcity especially if it can be supplemented by a small ration of lucerne hay or similar feed.
Annual yields of 20 to 40 tons per morgen can be expected under average conditions. As many as 40 sheep per morgen or more can be carried by this crop during the four winter months in the central Karoo. As a supplement for veld grazing it has also produced very favourable results.
Spineless cactus is adapted to a wide area, the minimum rainfall requirement for its cultivation being about 10 inches per annum. It responds best on deep fertile soils, and the fact that its prototype is found mainly on hillsides must not be taken to indicate preference for a stony habitat. Natural distribution is determined primarily by temperature factors and this fact should be borne in mind when selecting the site for a plantation.
Although differences in resistance to low temperatures are found in varieties, these differences are not significant enough to outweigh other considerations such as yields, palatability and absence of spines and spicules. The selection of a high lying site with a northeasterly aspect or otherwise sheltered position will do more to ensure success than reliance on the frost resistance exhibited by any variety.
Planting should take place during or soon after September. Late planting results in immature growth at the end of the Season, which is liable to be frosted during the following winter.
Preparation of the land by ploughing or contour strip ploughing should be done where possible. Planting on unprepared ground restricts growth.
The common method of establishing the crop is simply, by laying the leaves down with a clod of soil or a stone to hold the leaf in place but experiments indicate that upright planting gives more rapid early growth. Slight drying of the leaves before planting is generally advocated.
The rows should be sufficiently wide apart to allow a wagon to pass between them. The plants should be spaced not less than 6 to 8 feet in the rows.
The shape of the plant can be modified considerably by pruning during the first three seasons. By allowing two, or preferably three, leaves to develop from the basal member and again two or three from each of these, a relatively low frame can be developed. This is of importance where the crop is intended for grazing.
Spineless cactus can be grazed by small stock to good advantage provided overgrazing is strictly avoided. Grazing with large stock is less satisfactory because of breakage which usually results.
Experiments show that the plants can be harvested to the three main stems, referring to above, without affecting recovery adversely, however, grazing must not be done to this extent. Pruning after grazing to maintain shape, and feeding the prunings off the plantation is recommended.
Cactoblastis cactorum is widespread, and a constant lookout for its appearance in the plantation should be maintained. Its control is greatly facilitated by annual grazing and harvesting, and where the insect has made its appearance the plantation should not be allowed to grow freely. This obviously necessitates establishing not more than can be utilised annually.
For purposes of harvesting and grazing and for observing and removing Cactoblastis egg-sticks, close planting should be avoided.
While the term spineless is freely used, few varieties are entirely free of spines throughout the year. The small barbed spicules are often present on spineless varieties in large numbers and cause inflammation of the intestinal tract and should therefore deserve more consideration than has been given them in the past.
Of the 27 varieties being tested at the Grootfontein College of Agriculture, only the two varieties, viz., Protectorate and Arbiter, may be considered to be free of both spines and spicules throughout the year. Unfortunately these varieties are not good yielders. Certain varieties produce up to two crops of spines and three crops of spicules per annum.
Yields vary by over 600 percent, and a wide range in palatability exists. The varieties Nudosa, Montery, Robusta and Chico are definitely unpalatable and are not recommended for planting.
When freedom from spines and spicules as well as yielding ability, frost resistance and palatability are taken into consideration, Skinner’s Court must be considered the leading variety. Sicilian Indian Fig is not quite as high yielding as the former, but has other good qualities and is probably the most frost-resistant of the varieties grown at the Grootfontein College of Agriculture. The variety Malta is also high yielding and frost resistant, but is more spiny than the above.
Supply of Leaves
Owing to the spread of Cactoblastis and the limited quantities of the newer varieties available at the Grootfontein College of Agriculture, supplies to individuals are limited to 100 leaves of two varieties at 3s. per hundred leaves c.w.o., f.o.r.
Owing to scarcity of bags buyers must supply two bags per 100 leaves ordered, but these must not be forwarded until buyers have ascertained, that their orders can be met.
Farming in South Africa 17