EXPERIMENT STATION BULLETINS. 219 



slightly. The quantitj- of nitrogen and potash removed by this crop is simply enormous., 

 and the source of the former can be accounted for only through the assimilation of 

 atmospheric nitrogen by the tubercles on the roots. That the lucerne is capable of 

 growing successfully for a time without the addition of fertilizers is proven by the 

 experiments of Voelcker" who took a piece of "clover sick" land in the Stackyard field 

 at Woburn in 1889, sowed it carefully to lucerne and applied several forms of fer- 

 tilizers. To the first was given superphosphate and bone dust; to the second, sulphate 

 of potash ; to the third, sulphate of ammonia ; to the fourth, nitrate of soda ; to the fifth, 

 superphosphate, bone dust, sulphate of potash and sulphate of ammonia; and to the sixth, 

 the same as to the fifth except that nitrate of soda was substituted for the sulphate of 

 ammonia. A seventh plot was left unmanured. The amount applied was four hundred- 

 weight of each material, whether alone or in combination, with the exceptions of the 

 nitrate of soda and sulphate of ammonia, of which two hundredweight were applied. 

 Three, and sometimes four, cuttings were obtained each year, and the product weighed 

 green. "For the first seven years (1SS9-95) the manures showed no benefit, while the 

 sulphate of ammonia distinctly reduced the product. From 1896 onward there has, 

 however, been a distinct change in the application of sulphate of potash or of manures 

 containing it, having shown a marked increase. 



An examination of the yields from the unmanured plot, showed that for seven years 

 it held its own with the manured plots, when, evidently, the available potash, owing to 

 the enormous annual draft upon its supply, began to be exhausted. The fact that 

 annual applications of nitrogen during the seven years showed no benefit, gives further 

 evidence of the ability of the legumes to assimilate from the soil atmosphere sufficient 

 nitrogen for their profitable growth. 



FERTILIZING VALUE. 



A plant whose roots penetrate so deeply into the subsoil and which converts so much 

 atmospheric nitrogen into organic nitrogen can but add a material supply of fertilizing 

 elements to the farm. According to Headden, who noticed that the roots penetrated to 

 twelve and twenty-five hundredths feet in a homogenious clay, the roots within reach of 

 the plow added to the stubble left by the first mowing is equal to two-thirds of the 

 green lucerne removed. This material, together with the fertilizing value of the feed 

 removed, which if consumed on the farm will be largely returned to the land in the form 

 of stable manure, is, certainly an important factor in maintaining the fertility of the 

 land. 



There are numerous experiments on record where the beneficial effects of lucernes have 

 been very large, not only in improving the mechanical condition of the *• ; 1 but in 

 actually adding to its fertility. 



In a series of experiments performed at the Wyoming Experiment Station recorded 

 in Bulletin 44, the following results are summarized: "When alfalfa land waB plowed 

 and planted to wheat it produced $8 to $12 more value in wheat per acre than the 

 land which had grown potatoes and grain before." "When alfalfa land was plowed 

 and planted to oats it produced $16 worth of grain more than land which had grown 

 potatoes and grain before." "When alfalfa land was plowed and planted to potatoes 

 it gave $16 worth more of potatoes per acre than was obtained from land which had 

 grown potatoes and grain before." "By growing alfalfa the above increase of yields and 

 values were produced with absolutely no cost for fertilizing the land." 



In Bulletin 57, Colorado Experiment Station, Cooke compares alfalfa sod with old 

 land for growing potatoes. The average from a large number of plots gave 3,610 

 pounds of merchantable potatoes, compared with 1,277 pounds grown on equal area of 

 old ground. 



Numerous inquiries are made relative to sowing lucerne as a permanent orchard crop. 

 It is evident from the extensive root system developed by this plant that it would 

 probably rob from the trees some of the moisture and nourishment necessary for their 

 complete development. While no experiment has been tried at the College to determine 

 this, the following conclusion found in Experiment Station Report, volume 12, p. 104S, 

 gives conclusions from Hessische Landw. Ztschr. stating that "Alfalfa seriously retarded 

 tha growth of young apple trees as compared with trees grown on land in cultivated 

 crops and wheat." 



* Journal of the Royal Agricultural Society, 1900, pp. 603, 604. 



