Show concrete mulch the federal department of agriculture ture has been conducting experiments with permanent mulches of concrete iron cinders zinc line aluminum and other substances which cover the ground except spots where plants are to grow in the tests testa beans peas strawberries and other small fruit grew as well as with ordinary cultivation soils so covered since 1823 have continued productive it Is said that permanent mulch conserves moisture COD controls weeds and warms the tha soil early |