In southeastern Idaho, where annual precipitation is distributed relatively uniformly through the months of the year, reducing evaporation losses during fallow is still very important because of the low precipitation levels. Although water loss to weeds has been a very significant problem in the past, modem herbicides and tillage equipment combinations can effectively minimize weed growth throughout the entire fallow season. Papendick stresses that early and continuous weed control is important since large weeds and high weed populations can remove significant amounts of soil water. Minimizing weed and volunteer growth also appears to be important for reducing the potential for Rhizoctonia root rot and other soilborne diseases. Soil Type Soil type can influence water storage and retention during fallow through both soil water-holding characteristics and soil water conductivity properties.
Sandy soils have a lower storage capacity than silts and clays but have higher infiltration rates.
During extended dry periods with high evaporation potential, sands loose their liquid water capillary continuity to the surface more rapidly upon drying than do finer textured soils. On finer textured soils, a tillage mulch is often more important than on sandy soils to break the liquid capillary continuity to the surface in order to effectively control evaporation during extended dry periods. Consequently, different management strategies for water conservation are often needed for different soil types. Influence of Surface Residue Surface residue effectively reduces runoff by slowing surface water movement downslope, allowing more time for infiltration into the soil. Standing stubble traps snow uniformly over the field, reducing drifting.