FIELD CROPS. 527 



Legume bacteria, S. F. Edwards (Ann. Rpt. Ontario Agr. Col. and Expt. 

 Farm, 36 {1910). pp. 102, 163).—T\ie author reports the work done on the 

 preparation of various cultures of nitrogen-fixing organisms for inoculating 

 the seeds of alfalfa and other legumes, and the results of their use by various 

 farmers. Many farmers rei)ort a greater vigor and increased yield ranging 

 from 10 to 50 per cent from the use of the inoculated seeds. 



Nitrog-en-gathering' plants, K. F. Kellerman ( V. S. Dept. Agr. Yearbook 

 1910, pp. 213-218, pis. 8). — The author discusses the different groups of nitrogen- 

 gathering organisms, the different types of root nodules, and the relation of 

 nitrogen-fixing plants to the potential supply of nitrogen in the soil. 

 ' Three general groups of nitrogen gatherers are mentioned, viz, the anaerobic 

 species, with Clostridium as a type, the aerobic represented by Azotobactcr 

 species, and the symbiotic root nodule bacteria. In addition to the nitrogen- 

 gathering root tubercles of the Leguminosse. the author lists as probable nitro- 

 gen gatherers the organisms found in the root tubercles of alder {Alnus crispa), 

 Ceanothus amcricanus, Lcpargyrca canadensis, Eleagnus argentca, Ceanotlius 

 veltitinus, Comptonia pcregrina, Encephalartos villosus, E. horridus, Cycas 

 seemanni, and C. circvnalis. 



It is claimed that the economic maintenance of the agricultural nitrogen sup- 

 ply depends upon determining the proper roles of these various activities, the 

 possibilities of the control and economic enhancement of their desirable func- 

 tions, and the recognition of the practical limits of biological factors in farm 

 practice, as well as on when and how to use nitrogen fertilizers profitably. 



Studies on the organisms found in the root tubercles of cycads, F. Zach 

 (Osterr. Bot. Ztschr., 60 {1910), No. 2, pp. .'/.9-55).— In addition to bacteria and 

 an alga (Anabwna cycadearum) the author found in the root tubercles of Cycas 

 revoluta an intracellular hyphomcete the mycelium of which becomes digested 

 in a manner similar to that of the mycelium of the fungus in the root tubercles 

 of ElfeagiTUS and Sempervivum (E. S. R., 23, pp. 528, 629). 



The nucleus of the infected cell becomes degenerate and the starch disap- 

 pears, while there is an increased production of calcium oxalate in connection 

 with a diminished resistance of the cell invaded by the parasite. 



FIELD CROPS. 



[Field husbandry experiments], S. B. McCready and C. A. Zavitz (Ann. 

 Rpt. Ontario Agr. Col. and Expt. Farm, 36 (1910), pp. 35-37, 39-/f2, 171-247, 

 figs. 16).— The work of 1909 has already been noted (E. S. R., 23, p. 332). 



A statement as to the weeds which have proved most troublesome during the 

 season 1909-10 is followed by a discussion of the remedy for field bindweed 

 (Convolvulus arvensis). Among 10 weeds mentioned as recent introductions 

 full notes are given on Rocket (Eruca sativa), pineapple weed (Matricaria 

 suaveolens), and yellow or small alyssum (Alyssum alyssoides). 



From several years' tests of the efiiciency of iron and copper sulphate in the 

 destruction of mustard in grain crops it is stated that both substances are 

 successful, but that iron sulphate is the more satisfactory. On one farm a 

 solution of 80 lbs. of iron sulphate to 40 gal. of water was applied by means of 

 a potato sprayer with special broadcast attachment consisting of a rod about 

 11 ft. long with nozzles 16 in. apart. Although the mustard was very thick 

 and the nozzles too low to allow the spray to spread sufficiently, every mustard 

 plant was killed without injury to the oat crop. 



Tables state the amount of rainfall during the 6 growing months of each of 

 the past 11 years, the average grain yield during the past 28 years, and the 



