Show when soils cease to produce the trouble with soils when they ease to produce as they did when new is not that elements ot plant toca are actually exhausted from tho boll but the necessary forces for the liberation are exhausted one of topse forces Is bacteria it la estl mated that in the common soil there are bacteria to the ounce tebesa bacteria must have for their food dumns then they will liberate food for the growth of plants to be a good farmer one needs to grow legumes and other cover crop plants to turn under for humus and to encourage these bacteria to perform their in the soil |