Show Important Place for Legume Crop Do Not Improve Soil Unless Many Conditions Are First Right Legumes have had bad an Important place In crop production for many centuries No doubt one of at the chief reasons for tor the great popularity of or this class of crops Is the fact that under suitable conditions they may have hare a a. very desirable Influence upon the he crops which follow them The In Increased creased corn yields following the use of ot a clover crop as a green manure testify to the worth of legumes le for tor soil building purposes s. s i Soil Soli Improvement The Idea of soil Improvement Is so BO frequently associated ted with the term terra gume that one often overlooks the tact fact that all legumes are not equally Uy effective for this purpose according to O. O H. H Se Sears assistant chief of at soil biology at the college of ot agriculture University oi of Illinois As a matter of at tact fact legumes not only differ in their ability to improve crop yields but they may at times even have a tendency tendency tendency tend tend- ency to lower the fertility of the soil the rhe extent to which legumes are arc valuable val val- In soil Improvement will wUl depend upon spon a great many many conditions One of Df these conditions Is inoculation Legumes are considered soll soil build 1 ing lag crops primarily because they have I access to atmospheric nitrogen provIded provided pro- pro vIded their roots are well supplied with nitrogen-gathering nitrogen bacteria livIng living living liv liv- ing within the nodules on the roots of ot the plants Such plants are said to tobe tobe tobe be Inoculated Inoculated legumes thus may secure their nitrogen from the Inexhaustible supply of at the air If It not Inoculated however legumes like other kinds of plants must depend depend depend de de- de- de pend upon the soil for their nitrogen as well as their mineral requirements and since they are heavy heady feeders upon nitrogen and other plant food elements elements ele ele- ele- ele ments meats they may be the most effective effective effective tive miners of or soil fertility grown 1 on the farm To function as soil building crops legumes must therefore therefore therefore there there- fore be Inoculated Benefits Derived The method of utilizing the crop Is another Important factor In determining Ing the benefit to be derived from the growing of at a leguminous crop Under the best conditions even Inoculated legumes secure only a part of their nitrogen requirements from the air Approximately a third of the nitrogen I found In the legume plants comes comets I from the soil soU It Is apparent therefore therefore therefore there there- fore that the soil soU content of or this important ImI Im- Im I element can be Increased only by returning a portion of the plant to the soil solI In the form of at roots stubble residues and as green or stable ma ma- nure A larger proportion of or the tops must be returned In the case of at som some legumes than Is necessary with others tenths Nine-tenths of ot the soybean soy plant is contained within the tops while about one half the alfalfa plant is below the he ground Thus removing the whole soybean soy crop and returning nothing In the way of ot manure or orth th threshed eBbed straw would tend to deplete the soil even though the plants were Inoculated whereas the removal of ot fl n crop of altaI alfalfa fa would have a much less serious effect Soil Improvement can an be accomplished therefore therefore by returning returning returning re re- re- re turning a major portion of Inoculated legumes to the soil solI In one form or another |