Rapid transport of contaminants through the unsaturated zone of soils owing to macrospore flow has an unpropitious effect on the groundwater quality. Soil macrospores will be active only in the case if two conditions of macrospore flow are fulfilled: the macrospore network is open on the soil surface and rain (or irrigation) intensity exceeds a threshold value. If the intensity of irrigation following an application of agricultural chemicals is less than the saturated hydraulic conductivity of soil matrix, the chemicals will not be washed off from the soil surface with no benefit for plants but they will be settled in relatively immobile water in soil matrix. Destruction of macrospore openings at the soil surface (e. g., by ploughing) also prevents a rapid macrospore flow of chemicals into groundwater.