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http://www.extension.org/67702 Land application of manure in regions with intense confined livestock and poultry production is an environmental concern when land is limiting because it promotes soil phosphorus (P) surplus and potential pollution of water resources. A net accumulation of soil P results from the disproportion between lower nitrogen (N) and P ratio (N:P) in animal manure and the higher N:P ratio in harvested crops. Although manure can be moved off the farm, its transportation becomes less economical with increasing distances from the source. Thus, management alternatives to land application are needed to resolve agronomic P imbalances for more effective recycling of manure P.