1920] FIELD CROPS. 827 



barley, and in 1916 In cooperation withi the Idaho Experiment Station at the 

 Aberdeen Substation witli Hannoheii barley. Detailed weights, measurements, 

 and analyses of the individual kernels are included in tabular form, and, with 

 the aid of numerous graphs, are fully discussed. The results obtained and 

 conclusions reached may be summarized as follows : 



The removal of the awns from a barley spike had a marked effect on the 

 development of the kernels of tho spike, kernels from clipped spikes having 

 smaller volume and a lower weight of dry matter at maturity than those from 

 normal spikes. This difference was not held to be due to the injury or .shock 

 of removing the awns, as the kernels in the clipped spikes develoi>ed as rapidly 

 as those in the normal spikes for several days after the awns were clipped. 



About one week after flowering, coinciding roughly with the beginning of the 

 period of rapid starch infiltration, the dep<isit of dry matter in the kernels of 

 the normal spikes began to exceed that in the kernels of the clipped spikes. 

 The daily deposit of nitrogen and ash was found to be more nearly equal in the 

 two classes of spikes than was the deposit of starch. In normal .spikes at 

 Aberdeen, Idaho, the awns contained more than 30 per cent of ash at maturity, 

 but when the awns were removed a part of this ash apparently was deposited 

 in the rachis. The rachises of the clipped spikes contained about 25 per cent 

 more ash than the rachises of the normal spikes. 



The additional ash in the rachises of the clipped spikes was thought probably 

 to be responsible for the tendency of these spikes to break. The indications 

 were that the elimination of the awns resulted not only in lower yields but 

 in shattering as well. 



From results of experiments conducted it appeared that hooded and awnless 

 barleys generally yielded less and shattered more than awned varieties, and 

 there seemed to be physiological reasons for this fact. These results led the 

 authors to suggest that it may be possible to produce nonshattering hooded 

 and awnless sorts by using parents which normally have a low percentage of 

 ash in the rachises, and to obtain strains that will give good yields und6r arid 

 conditions. Under humid conditions it is deemed likely that the objections to 

 the awns are more easily met by the use of strains with smooth awns, which, 

 so far as known at present, have no physiological Hmitations. 



Castor oil as a crop, E. Mathieu (Gardens' Bui. Straits Settlements, 2 

 (1920), No. 8, pp. 282-294). — This includes a brief description of the castor bean, 

 methods of cultivation recommended for the Malay Peninsula, varieties, insect 

 and disease pests, and notes on oil extraction and utilization. The practice of 

 intercropping castor beans with peanuts is said to return a net profit estimated 

 to range from $396.8.j to $532.50 per acre. 



Freezing injury of seed corn, T. A. Kiesselbach and J. A. Ratcliff (A^e- 

 braska Sta. Research Bui. 16 (1920), pp. 96, figs. 22).— The authors give the 

 results of a study of conditions under which freezing injury may occur to seed 

 corn, indicating some of the changes in the embryo resulting from such injury 

 and pointing out ways by which seed corn of strong vitality and satisfactory 

 yielding capacity may be obtained. 



It is claimed that the embryo and endosperm of a corn kernel develop ap- 

 proximately at the same rate from the time of fertilization until maturity, 

 and that the power of germination is attained in about 20 days after fertilliza- 

 tion. The embryo and endosperm In an air-dry kernel contain practically the 

 same amount of moisture. However, in the period prior to maturity the embryo 

 has a higher water content than other portions of the grain. 



When inmiature or moist kernels of corn are exposed to freezing tempera- 

 tures, ice is said to form in the intiTcellular spaces and in the larger spaces 



