title: Effect of organic matter supplementation on nitrogen transformations in soils. I. Chemical and bacteriological changes.
abstract: The effect of supplementation with different organic materials on nitrogen transformations and on certain bacterial groups in soil was studied. Addition of wide C/N ratio organic matter, sawdust and maize stalks prevented NO3-N from being lost through leaching out or dentrification and favoured the development of Azotobacter and N2-fixing clostridia that in turn resulted in marked gains in nitrogen through N2-fixation. Nitrifying bacteria were adversely affected. Application of such materials together with high amounts of NH4NO3 lessened nitrogen losses in drainage water but increased losses through denitrification. Nitrogen-rich organic matter resulted in higher losses in nitrates from soils in comparison to those of wide C/N ratio organic materials.
mesh_terms: D001395:Azotobacter; D003013:Clostridium; D005308:Fertilizers; D009584:Nitrogen / Q000032:analysis*; D009586:Nitrogen Fixation; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
chemical_list: D005308:Fertilizers; D012987:Soil; D009584:Nitrogen