“…The nitrogen should also be supplied at a time when crop productivity is nitrogen-limited (Chambers and Smith, 1998). Various substances have been tested for their efficacy in preventing gaseous nitrogen losses from manure during storage (Pratt et al, 2006). Most manure treatments involve either substances which chemically combine with potential 'pollutants' such as nitrogen or phosphorus or substances which act as adsorbents or chelating agents.…”