The invention relates to processes for reducing ammonia loss and odor from organic material or waste to the atmosphere. A plasma generator is applied to upgrade organic waste and manure with a mixture of acidic nitrates and nitrites. The present invention also relates to an acidic nitrate solution, suitable for reducing ammonia loss and odor from organic material or waste to the atmosphere, and a process for producing such an acidic nitrate solution. The invention further comprises plants for reducing ammonia loss and odor from organic material or waste to the atmosphere.