In Some Places Inoculation not Necessary 



"But how is it that over in our country where we have never in- 

 oculated we have been growing alfalfa for years with good success?" 

 asked a farmer of one of the Lake Shore counties of Wisconsin. 



That was a good question. And what he says is true. Fields 

 along roadsides where sweet clover grows abundantly are inocu- 

 lated by the bacteria-laden dust that blows over them. Further 

 than that, soils rich in lime, even far distant from any such a source 

 of inoculation as sweet clover, will produce successful crops of alfalfa 

 if in addition to their lime content they abound in fertility, particu- 

 larly organic matter. In such cases alfalfa draws on the soil for its 

 nitrogen instead of getting it from the air, until it becomes self-inoc- 

 ulated. 



But no doubt such fields would give larger yields of alfalfa hay 

 the first two or three years if the bacteria were supplied in large 

 enough numbers by proper inoculation to effect an immediate de- 



Fig. 23. Inoculation Increases the Yield and May Prevent Failure. 



velopment of nodules on the roots. Often in such cases, especially 

 on poor soils, the second and third crops grow poorly, due to a lack 

 of sufficient nitrogen for the rapid growth of the alfalfa. Yes, there 

 are those who grow alfalfa for the first time without inoculation, 

 but for every success ten or more failures will be reported. 



Unseen Builders of Fertility 



Not long ago I walked out into an alfalfa field with a German 

 farmer. He was enthusiastic about alfalfa, having twenty acres 

 well established. "I did like you said when I wrote you three years 

 ago. I hauled one load of sweet-clover dirt and spread it over one 

 acre just before I seeded my alfalfa. But one corner I left without 

 the dirt. That winter-killed bad. Blue grass soon came in where 

 I did not inoculate. Where I spread the dirt I got a fine stand. 

 Why is that?" 



With a shovel we carefully dug up some of the alfalfa roots. We 

 broke away the dirt and found an abundance of nodules. They 

 were the first he had ever seen. 1 then explained that those swel- 

 lings were the homes of the bacteria he had introduced into his soil 

 with the sweet-clover dirt and that the bacteria converted the nitro- 

 gen gas of the air into a liquid form which was an actual fertilizer 

 for the plants. (See Figs. 28 and 29.) 



We went over to the little strip he had left uninoculated and made 

 a search .for nodules. They were very hard to find. He was 



29 



