Publisher's Synopsis
Encyclopaedia of Organic Fertilizers: Basic Concepts to Applied Outcomes comprehends chapters of review ar- ticles and case studies and provides information in field of organic farming and fertilizers. Organic farm- ers are limited to "natural" fertilizers which for non-legume, large acreage, crops boils down to manure or composted manure (Organic growers are not the only ones that use manure, but the problems occur for all). Some of the nitrogen molecules in an "organic" fertilizer are exactly the same chemicals as in "synthetic" fertilizers - urea and ammonia. Some of it is in more complex biologically formed molecules like amino acids, nucleic acids and a variety of intermediate metabolites and structural molecules. That is why organic fertilizers are "slow release" forms of nitrogen. Over time, soil microbes convert those more complex forms into exactly the same nitrate ion that comes from a synthetic fertilizer - the nitrate that plants can use (and which can become a pollutant of the water or atmosphere). The problem is that the conversion process does not match the crop demand. To achieve good yields, Organic growers need to apply very high amounts of total nitrogen so that enough is available when the crop needs it. Much of this nitrogen continues to be turned into nitrate well after the crop is using it and so it is well documented that this form of fertilization leads to water pollution issues. This is why farmers are being payed to truck manure far away from the waterways that drain into the bay. Slow-release nitrogen sounds a lot better than it is. Organic fertilizers also have the problem that they contain more phosphorus than is needed if they are used at the rates that make sense from a nitrogen point of view. Growers using manure or com- post pick rates based on nitrogen, but that means that phosphorus is over-supplied. This too leads to water pollution.
