OCR Text |
Show GREEN MANURING. Only Legumes Add More to Soil Than Elements Taken From It. Green manuring Is tho plowing un-dor un-dor of nny green crop for tho purposo of getting fertility nnd decaying vegetable vege-table matter into tho Roll. If It Is do-sired do-sired to add fertility, then somo crop must be plowed under that has In it somo fertility that it did not tnko out of the soil, for It is evident that If tho plant plowed under has In It only tho fertility that was taken out of tho soil, nothing Is galnod, so far as fortuity Is concerned. So far as wo know, up to this tlmo, only plants that havo pods hnvo in them at any tlmo mora fertility than was taken out of tho soil. Even those plants do not havu moro fertility than what came out of tho soil, unless llttlo knots nro found on tho roots, which knots aro known ns nodules. In thoso nodules nro little lit-tle plants called bactorln, which tnko frco nitrogen gas from tho air and mnko It Into n form of nitrogen that can bo assltnllnted by tho plants. Such plants when turned undor curtail cu-rtail tho soil by Increasing Its nitrogen content. This must bo understood by every person that raises n crop to turn undor. It Is doubtful If It pays to turn undor other crops, ns In that caso tho only gain to tho soil Is tho humus, and In many cases the soils havo In thorn enough humus and do not need Increased humus content. |