Photo credit: WVC 2006-12 – Algiers 01-3
Opuntia against Drought
by Graham Knight
“!n much of west Texas, the iconic Prickly Pear cactus — with its plum-like fruit and forbidding spiked pads — is at best considered a nuisance, and at worst a downright hazard to livestock. But in most of the rest of the semi-arid world — from Mexico and Chile, large swaths of India and South Africa, as well as Spain and Morocco — Opuntia ficus-indica (Prickly Pear) is used in dye-making, as feed for livestock, and, little by little, as feedstock for anaerobic biogas production.”
Here is report from 2008. Even then it was in wide use
The search for appropriate plant species able to grow and to produce in arid areas was of a permanent concern of most people leaving in harsh environments. Drought is a natural and normal attribute of the arid lands and arid and semi-arid climates. The South African stock industries regularly suffer exceptionally large losses as a result of a scarcity of food during droughts. There is thus a shortage of low cost fodder, especially during drought. Therefore livestock farmers need to be better prepared to overcome drought conditions.
One way to lessen the devastating effect of droughts is to establish drought-tolerant fodder crops in arid and semi-arid areas. Prickly pear (Opuntia) and other cactus plants possess the remarkable quality of being able to take up and store water within a reasonably short time. For long periods these plants are then able to survive with very little rain. This quality of theirs makes them particularly useful, since periodic droughts are a phenomenon in many countries, particularly Southern African countries.
Agricultural drought may be defined as a deficiency of rainfall in respect to the median or to the mean that seriously impairs agricultural production for a period of several months to several years, extending over a large geographical area (WMO,1975). Opuntias (Cactus) are now part of the natural landscape and the agricultural systems of many regions of the world. Some species are even naturalized weeds in countries such as South Africa and Australia where the environmental conditions are particularly favourable.
In many different countries the Opuntias and their products serve various purposes (as food, forage, energy, medicine, cosmetic, agronomic and others). It is indeed difficult to find more widespread and better exploited plant, particularly in the subsistence economy of arid and semi-arid zones, where farmers due to the lack of natural and productive resources, must look to those few species that can profitably survive and produce. Thus Opuntias have become an endless source of products and functions, initially as a wild plant and, later, as a crop for both a subsistence and a market-oriented agriculture (Barbera, 1995). This is supported by the daily pattern of carbon dioxide (CO2) uptake and water loss, primarily at night when plants open their stomates. The carbon dioxide taken up is incorporated into various products of photosynthesis which takes place only in light. The fact is that the opening of the stomata at night when temperatures are lower and humidity is higher, resulted in a lower water loss (Noble, 1995). Thus Opuntia plants attributes makes it an ideal “drought insurance” as it is adapted to withstand severe drought conditions and still produce fodder at a low cost.
The cactus pear can also be used in agri-forestry systems with legumes and annual crops. Cactus pear can play a stabilizing role in agriculture as it can prevent stock losses during droughts, save natural grazing from over-utilization, increase farm income and alleviate poverty in rural areas (Potgieter, 1993). Rodriguez (1997) mentioned that traditionally, prickly pear cactus has been used as fruit, vegetable and forage.
Spineless cactus pears are valued by many farmers because of their drought resistance, high biomass yield, palatability and adaptability to a range of soils and climatic regions.
Fruit production from spineless cactus for export is already an established and integral part of some farming enterprises in the Limpompo province. The expansion of this farming practice to other provinces in South Africa currently enjoys high priority in research.
Besides the income from fruit production it has tremendous potential as regards job creation and small-scale farming. Fruit production necessitates the yearly pruning of the plant to get rid of diseases infected parts and to facilitate the harvesting of fruits. This available fresh plant material is mostly used as feed for sheep and beef cattle. The cactus material could however be used more efficiently and strategically if it is preserved and stored as silage.