(Thio)acyl-pyrazole derivs. used as soil nitrification inhibitors - e.g. in soil treated with nitrogen-contg. fertiliser

摘要

New agents for inhibiting or regulating nitrification of ammonium nitrogen in culture media contain as active ingredient =1-acyl-pyrazole of formula (I). In (I), R' and R3 are H, halogen, opt. substd. alkyl or aryl, and R2 is H, halogen, alkyl or NO2. When R' and/or R3 is/are H or alkyl, then R4 is opt. substd. alkyl, alkenyl, aryl, opt. substd. aryloxy, alkylmercapto or arylamino and X is O or S. When R' and/or R3 is/are halogen or aryl, then R4 is opt. substd. alkyl, alkenyl, aryl, opt. substd. alkoxy, aryloxy, alkylmercapto, arylmercapto, or amino opt. substd. by alkyl and/or aryl, and X is O or S. The alkyl and aryl residues may be substd. by halogen, CN, COOH, alkoxycarbonyl, NO2, OH, alkoxy, aryloxy, amino (in turn opt. substd. by alkyl and/or aryl, or acyl), alkyl or aryl. Used to prevent nitrification of ammonium nitrogen (esp. that added in fertilisers) in order to minimise loss of nitrogen by leaching out of the more soluble nitrate nitrogen formed by the nitrification process. This gives improved utilisation of nitrogen added in fertillisers and reduces nitrate pollution of ground waters. (I) have adequate water-solubility and are non-volatile. Their stability ensures prolonged action. Activity is evident with low concens. of (I).