Recent advances in forage production from spineless nopal (Opuntia spp.) in the brazilian Northeast.

Introduced as an ornamental plant and to raise cochineal (Cocus cacti), at the star of this century, the nopal was disseminated as a forage plant. At the present time, there is a growing area of c. 400,000 hectares, located mainly in the "Agreste" region. The "Sertao" region is less appropriate to il. The research works were startedin 50' adnd were almost stoppedin the 70' s, being re-initiated after the big drought of 1979-82. The following points have been set up: the dry matter productivity of glant nopal (O. ficus-indica) in the Agreste is 11 t/hectares in biennial harvests, while in the Sertao it is 10.5 t/hectare in triennial harvests; the recommended planting distance are 3 m x 1 m x 0.5 m (double lines), which permit mechanizaton; the types giant and round nopal (also O. ficus-indica) have a similar production and have yield 50% more than sweet nopal (Nopalea cochenillifera); manume fertilizing (10-20) t/hectare has been the main factor increase production; intercropping with annual crops (corn, Vigna beans, sorghum, etc) is very common, for although it decreases production, it is a way of lowering the costs of planting and deweeding the nopal areas; the shading by Prosopis juliflora has so far shown a tendency to benetit the cactaceae. It will probably be a advantageous in the Sertao, where the environmental conditions are less appropriate to nopal growing, such as high daily temperature (max's mean = 31 oC) and absence of low temperature at nigh (min's mean = 20 oC); in cattle feeding, the nopal, although poor in protein and phosphorus, and showing inappropriate balance between calcium and phosphorus, is rich in soluble carbohydrates. In dairy production, it has been as efficient as corn silage. Other points are being emphasized, that is, in situ water harvesting can promote substantial increase in nopal production. Another study involvels a clone competition with the objectives of indicating more productive and high protein and phosphorus content varieties, resistant to cochineal (Diaspis echinocacti), an insect that is destroying the nopal areas of the region