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If crop evapotranspiration (ETc) is used for the irrigation scheduling, the crop should be irrigated. a the soil-water content the sum of daily ETc since the last irri ation ex �° capacity. This ensures thatg seeds the allowable depletion" from field will not fall below the yield threshold and reduce yield. ri Others factors- . such as irrigation system capacity, soil infiltration rates, water delivery constraints, etc. dictate when you irrigate. The depletion from field capacity that is actually used for timing is F. called the "management allowable depletion"to ensure optimal crop production. Dense layer Bulk density), grams/cm3: Bulk density, soil mass per unit volume, is expressed in grams per cubic centimeter. It affects finfiltration, permeability, and available water capacity. Coarse textured soils have only a slight limitation because of bulk density. Medium to fine textured soils in which the bulk density.in the surface layer and subsoil is less than 1.7 91cm3 have slight limitations for application of agricultural wastes. tes. Medium to fine textured soils in which the bulk density in these layers is more than 1.7 g/cm3 have ` moderate limitations. fh site soils have the Faulk density bellow 1.7 g/cm3, which classifies them as having a ht limitation to applications of agricultural wastes. It is recommended that applications of solids are when soil moisture content is such that the field is in tillable condition. Applications reduce bulk density and minimize compaction. Agricultural waste application equipment may compact the soil when the waste is applied to soil by spreading or injecting and soil moisture content is at or near field capacity. Agricultural wastes i should be applied when soil moisture content is significantly less then field capacity to prevent ' compaction. Agricultural wastes can be surface applied to medium to fine textured soils that have bulk density less than 1.7 glcm3. Liquid waste should be injected and application rates reduced when the bulk density of medium to fine textured soil is equal to or greater than 1.7 g/cm3. Injection application and reduced application rates on these soils help to prevent liquid waste runoff and compensate ` i for slow infiltration. . Incorporating wastes that have a high solids content with .high levels of organic'carbon reduces E the soil surface bulk density and improves soil infiltration and surface permeability. The high bulk density associated with coarse textured soils does not impede or affect the application of agricultural wastes. The high permeability rate of coarse textured soils may affect the application rate because of the potential for ground water contamination. on. Refer to page 22 for Endnotes and Reference Sources r r Western Dairy Design Associates, Inc.2003 Page 11 fill