Aqueous adjuvant concentrate with improved spray drift properties and method for its preparation comprising the steps of: i) dissolving from 15 to 30 % by weight, on the weight of the final concentrate, of ammonium sulfate in water ii) adding to the solution from 1 to 10 % by weight, on the weight of the final concentrate, of anionic esters of alkyl polyglycosides iii) dispersing in the solution from 2 to 10 % by weight, on the weight of the final concentrate, of hydroxypropyl guar or hydroxypropyl guar acetate iiii) adding ammonium sulfate to the dispersion to reach an ammonium sulfate final concentration comprised between 33 and 40% by weight.
