FIELD: agriculture. SUBSTANCE: method involves treating agricultural land with liquid having concentration determined from formula: 
, and liquid flow rate per second determined from formula: 
, where k is liquid concentration, %; L is length of land to be treated, m; Dch is biologically optimum (predetermined) dose of pesticide (chemical) for carrying out given kind of treatment, kg(l)/ha; b is sprayer width; 
is number of dual passes of sprayer along field for single cycle, with this number being approximated to whole ordinal number; Gmax is maximum one time charging of sprayer tank with liquid to be sprayed, l; Kst is standard concentration of liquid, %; v is speed of advancement of sprayer along land to be treated, km/hour. EFFECT: increased efficiency without deteriorating quality of treatment of agricultural land.
