780 EXPERIMENT STATION RECORD. 



the crushed stems and this change in plant circulation has been 

 regarded as a factor in influencing productiveness. According to 

 Schumacher, rolling also exerts an advantageous influence, especially 

 in the case of potato plants, in so far as the tension of the tissues is 

 increased by injury of the stems and assimilation in the uninjured 

 portions is increased in the same degree. 



How far these assumptions correspond with actual conditions the 

 author was unable to determine from i)reviously reported work, as the 

 experiments had not been made with sufticient regard to the require- 

 ments, and contradictory results had been obtained. 



To establish a satisfactory basis for the study of these points a 

 series of vegetation experiments was carried out by the author in 

 which plants grown under similar conditions on like plats remained 

 undisturbed or were rolled down at different stages of develoi>ment. 



The tests were made with cereals, legumes, rape, and Camelina sutira 

 for 2 years, and with ijotatoes for 4 years. Tables are given showing 

 detailed data for each crop, and the conditions and conclusions are 

 fully discussed, the work upon potatoes being considered separately. 



The tables show, according to the author, that with few exceptions 

 rolling the grain crops resulted in a decreased yield; that the injurious 

 efl'ect was more marked the later the rolling was done, and that under 

 favorable vegetative conditions the injury was slight or there was even 

 a gain. 



With potatoes the results were more favorable, as the yield was in- 

 creased when the plants were rolled in their early stages of develop- 

 ment (June 11 to 2(3), and was sometimes increased and sometimes di- 

 minished when the fully formed vines were rolled (July 16 to 2G). The 

 influence of the weather was as marked upon the potatoes as upon the 

 grains, the favorable effect of the rolling being increased and its injuri- 

 ous efl'ect lessened when warm, moist weather followed the operation. 



The author believes rolling useful for breaking the crust which may 

 form over the seed upon some soils, for reestablishing plants upheaved 

 during the winter, and for compacting soils in regions exposed to hot, 

 drying winds ; but the experiments aftbrded no test upon these points. 



The nitrogen requirement of barley, II. Hellriegel et al. (Zfschr. Ver. Biihenz. 

 hid., 1S97, Feb., pp. 141-217). 



Chicory culture in Nebraska (Amer. Agr. (middle ed.), 59 {1897), No. 12, p. 353, 

 fig. 1). 



Important facts about corn, W. H. Jordan (Maine Sta. Rpt. 1S95, pp. 127-130). — 

 A reprint of Bulletin 17 of the station (E. S. R., 7, p. 121). 



Forage conditions of the prairie region, ,1. G. Smith ( V. S. Depi. Agr. Yearbook 

 lS05,pp. 309-324, figs. 5). — A popular article on the wild lorage plants of the prairie 

 regions. Notes are given on the bine stems (Avdropogo)i fiircatiis, A. nutans, and A. 

 scoparius), switch grass (Panicum virgafiim), the wheat grasses (Agropymm spicatum, 

 A. caninum, A. richardsoui, A. tenerum, and A. rcpens), the gramas or mescjuite grasses 

 (Boutelona ctirtipendiila, B. oUgostachya, and B. hirxiifa), hnffalo grass (Bnchloe dac- 

 tyloides), -pvame June grass, (Eatonia ohfiifiafa and Kaleria cristata), fresh-water cord 

 grass (Spartina cynosuroides), wild-rye grass (Elymiis sp.), blue stems (Calamagrostis 



