Influence of municipal waste compost amendment on soil water and evaporation

Municipal Waste Compost was added to soils in the glasshouse and field to assess its impact upon soil physical properties. Application was by mulch and incorporation, and the amelioration of temperature, soil water content, unsaturated hydraulic conductivity, and evaporation were investigated. Incorporation in the glasshouse pot experiments increased early season evaporation, while compost applied by either means raised soil temperature. In later stages of drying, the presence of compost reduced the evaporation rate. In the field, compost addition to trials of maize (Zea mays var. Melody) improved retention of soil water during a normally wet summer, but not during a very dry summer. Furthermore, soil temperature tended to be reduced by mulching. It is concluded that compost application is beneficial to soil water retention and its subsequent utilization by a crop in conditions of normal rainfall under a temperate climate. Furthermore, it is concluded that the common practice of extrapolating glasshouse-derived information to field conditions creates serious problems, at least in soil physical experimentation.