title: Brassicaceae tissues as inhibitors of nitrification in soil.
abstract: Brassicaceae crops often produce an unexplained increase in plant-available soil N possibly related to bioactive compounds produced from glucosinolates present in the tissues. Our objective was to determine if glucosinolate-containing tissues inhibit nitrification, thereby potentially explaining this observation. Ammonium, NO(2)(-), and NO(3)(-) N were measured in soils amended with Brassicaceae ( Isatis tinctoria L., Brassica napus L., Brassica juncea L., and Sinapis alba L.) tissues containing different glucosinolate types and concentrations or Kentucky bluegrass ( Poa pratensis L.) residues with equivalent C/N ratios as the Brassicaceae samples. There was greater accumulation of NH(4)(+) N in soils amended with tissues containing high glucosinolate concentrations as compared to soils amended with tissues containing no or low glucosinolate concentrations. Nitrite N was detected only in soils amended with Brassicaceae tissues having the highest glucosinolate concentrations. The positive correlation of both NH(4)(+) and NO(2)(-) N accumulation with the glucosinolate concentration indicates the participation of glucosinolate hydrolysis products in nitrification inhibition.
authors.affiliation: Departments of Chemistry, Biology, and Environmental Studies, Trinity Western University, Langley, British Columbia V2Y 1Y1, Canada.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Brown
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Morra
mesh_terms: D019607:Brassicaceae / Q000737:chemistry*; D005961:Glucosinolates / Q000008:administration & dosage* / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D012987:Soil / Q000032:analysis*
chemical_list: D005961:Glucosinolates; D009566:Nitrates; D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D012987:Soil; D009584:Nitrogen