Use of formulations as compatibility agents A formulation for use as a compatibility agent in pesticide/liquid fertiliser formulations comprises: a) an N-acyl sarcosinate, or a salt thereof, having the formula: RCON(CH3)CH2COOX (I) wherein R is a straight or branched chain alkyl or alkenyl residue having from 2 to 18 carbon atoms and X is hydrogen, an alkali metal, the ammonium radical, a primary, secondary or tertiary amine group or a hydroxyalkylamine group; and b) a solvent or mixture of solvents for component a).