NATURAL ZEOLITES – REMEDY FOR CONCENTRATED ANIMAL FEEDING OPERATIONS AND SUSTAINABLE AGRICULTURE

The disposal and use of animal manures are major concerns of Concentrated Animal Feeding Operations (CAFO) worldwide. Concerns are both environmental and economic: environmental because of noxious odors from ammonia volatilization, leaching of nitrates into ground and surface waters, and excessive amount of heavy metals in the manure; economic because of disposal costs, compliance of envi-ronmental regulations, and the loss of valuable nutrients from the farming system. A central goal of sustai-nable farming systems is to convert waste products into a valuable resource. Livestock manure from CAFOs is often spread on cultivated fields, but the loss of manure nitrogen (often over 50%) through ammonia volatilization and nitrate leaching makes the nitrogen:phosphorus (N:P) ratio to low for balanced and appropriate crop applications. Both empirical evidence and the chemical composition/structure of natural zeolites support their mix-ture with animal manures as an environmentally friendly approach to solve the above problems. Natural zeolites are hydrated sodium or potassium, calcium aluminosilicate minerals found in many countries. In particular, clinoptilolite, one of 82 natural zeolite minerals, is uniquely characterized by its capabilities of absorption, adsorption, and cation exchange. Clinoptilolite has a framework structure that permits adsorp