230 EXPERIMENT STATION RECORD. 



198.2; 4,707.5, 197.4; and 4.943.4, 177.7', The yields resulting from variation in 

 total depths varied similarly to those from different depths at each irrigation. 



The examination of the root systems showed that the plants had deeper roots 

 on the shallow soil than on the deepest soil. The plants on the deepest soil 

 plat i-eceiving 5 in. of water had better developed root systems than those re- 

 ceiving 2 in. On the shallow soil there was little difference for the different 

 depths of irrigation. 



Effect of frequent cutting on the water requirement of alfalfa and its 

 bearing on pasturage, L. J. Briggs and H. L. Shantz {U. 8. Dept. Agr. Bid. 

 228 (1915), pp. 6, figs. 2). — This paper describes a pot experiment conducted as in 

 those previously noted (E. S. R., 29, p. 825), and gives the results obtained with 

 Grimm alfalfa. Three cuttings were made of the plants of the A series of pots 

 during the season, and the plants of the B series were also cut back weekly 

 during the middle period, somewhat as in pasturage. 



The results showed that " the water requirement of the two series during 

 the first period (i. e., up to the time of the first cutting) was practically the 

 same. The mean ratio of the six pots of series A (cheek) was 600±17 and of 

 series B 615±6. The difference is less than the probable error. 



" During the second period the water requirement of the check series was 

 853±13, while the series which was cut weekly during this period gave a water 

 requirement of 975±23, an increase of 14±4 per cent. It thus appears that 

 alfalfa is slightly less efficient in the use of water when subjected to weekly 

 cuttings. 



" During the third period, when both sets were again treated alike, the water 

 requirement of the check series (A) was 421±10 and that of series B 479±16. 

 The B series thus shows during the third period also a slight increase (14±4 

 per cent) in water requirement compared with series A." 



It is noted that when the water requirement is based on the total dry matter 

 produced during the season, series B was practically as efficient as the check 

 series. The explanation seems to have been found in the relative yields during 

 the second period, during which time series B produced only 18 per cent of its 

 total dry matter, while the check series produced 38 per cent. 



" The check series produced practically the same amount of dry matter dur- 

 ing the second period as during the first. Series B produced only 30 per cent 

 as much during the second period, the small plants being unable to elaborate 

 plant material as rapidly as the larger plants of series A. Series B was also 

 maintained during the midsummer period with an actual expenditure of only 

 one-third the water required by the check series. This forced economy in the 

 use of water through frequent cutting seems not to be without effect on subse- 

 quent production. Series B produced only 48 per cent as much dry matter 

 during the third period as the check series, while during the first period, not- 

 withstanding the shorter period of growth, series B produced 60 per cent 

 as much dry matter as the check series." 



The bearing of these results on the management of alfalfa lands is discussed 

 to show a means of limiting the growth of the crop, so that its demand for 

 water will not exceed the available moisture supply, by a system of pasturage 

 in midsummer. 



• Barley in the Great Plains area: Relation of cultural methods to produc- 

 tion, E. C. Chilcott, J. S. Cole, and W. W. Burr (U. 8. Dept. Agr. Bui. 222 

 (1915), pp. 32, figs. 2). — The study of the yields obtained under various methods 

 of seed-bed preparation as here presented is made in such a way as to show 

 the effect of the crop immediately preceding and the tillage involved in pre- 

 paring the seed bed for barley. The area included in these investigations 

 covers parts of ten States and about 400,000 sq. miles of territory, and ranges 



