IRRIGATION NORM DETERMINING METHOD Russian patent published in 1998 - IPC

FIELD: irrigated agriculture. SUBSTANCE: method involves wetting soil layer by supplying water from below; sampling soil and determining soil moisture content; registering wetting process stabilization moment; plotting moisture content diagram and determining irrigation norm; measuring height of moistened zone in predetermined time intervals during wetting of soil; setting dependence H(w)= f (t) and determining average value of equilibrium moisture content in rated soil layer on the basis of dependence curve and equilibrium moisture content diagram. Irrigation norm is determined by formula: , where γ - is volumetric weight, t/cub m; h(w) is thickness of wetted soil layer, m; W(p) average value of equilibrium moisture content, % of weight; W(ir) moisture content of wetted soil layer. Method allows optimum irrigation norm corresponding to minimum irrigation water loss to be set. EFFECT: increased efficiency, reduced loss of irrigation water, provision for keeping quality of irrigated land and level of underground water. 4 dwg