FORAGE POTENTIAL OF CACTI ON DRYLANDS

Drylands cover 40% of global land area and host more than two billion people. Pressure on natural resources on these areas is enormous, mainly on the most densely populated regions. Global commodities prices are peaking high leading to higher feeding costs. Increasing crop production on drylands is necessary to feed the herd at lower cost and increase food security by producing locally. Adapted perennial crops with forage potential are necessary to fill this gap. Forage production from cacti (Opuntia and Nopalea) fits well in this scenario. Potential dry matter production of 20 Mg ha^-1 yr^-1 has been often achieved in well managed rainfed systems in the Brazilian semiarid. Maize grain average production in this same region is 500-600 kg ha^-1 yr^-1. Agronomic practices such as manure application, weed control, and dense populations are necessary to increase cactus yield. Cactus breeding also plays important role producing pest tolerant cultivars with increased yield. Different strategies are available for forage production systems including scattered planted cactus in marginal lands (< 200 mm yr^-1) to recover vegetation and protect soil from erosion, alley cropping systems with forage legumes or cash food, intensive cactus production in rainfed system, and more recently, irrigated cactus with a minimal amount of water (2.5 mm week^-1) using drip irrigation. Cactus usually presents high energy value (650-700 g kg^-1 TDN), low crude protein (40-70 g kg^-1), low NDF (250-300 g kg^-1), and high mineral concentration. When fed in a total mixed ratio, cactus may provide nutrients for 25-30 kg cow^-1 day^-1 of milk. Small farms predominate in the most densely populated drylands. Increasing cactus productivity is a way to reduce pressure on natural resources and increase sustainability and livelihood in these rural areas.