430 EXPERIMENT STATION RECORD. [Vol.40 



sonal moisture penetrated each year to the subsoil moisture. Spring wheat, 

 barley, and oats removed moisture from the soil to a depth of from 5 to 6 ft., 

 alfalfa from 9 to 10 ft., and brome grass from 6 to 7 ft., plant roots removing 

 the moisture from the soil zones where it is most available. Less than a third 

 of the annual rainfall has been retained in" clean summer-fallowed land. Ex- 

 cept in seasons of heavy rainfall, small grains grown on summer-fallowed land 

 removed all the available soil moisture by the time the grain was in the heading 

 stage, the yields being largely dependent on the seasonal rainfall received after 

 this period. Manuring and deep plowing held a large percentage of the sea- 

 sonal moisture in the surface soil, while plowing to a depth of 5 or G in. with 

 a shallow surface soil mulch permitted the moisture to penetrate Into the sub- 

 soil. Intertilled crops such as corn did not start active growth until after the 

 greater part of the seasonal rainfall had fallen. These crops matured early, 

 leaving a portion of the seasonal moisture in the soil for subsequent crops. 

 Weeds were found to be by far the greatest factor in removing the moisture 

 content of the summer fallow during the summer months. 



Spraying perennial weeds with sodium arsenite is said to have given promising 

 results with poverty weed [Iva axillaris) and blue lettuce {Lactuca pulchelia), 

 while the results with Canada thistle (Carduua arvensis) and weeds of the 

 same general habit of growth were less encouraging. 



The maximum potato yield for the season was 38,270 lbs. per acre from 

 Mills Prize. Of seed selected in various ways thai chosen by noting the vigor 

 of the vines gave the highest yield, resulting in increases in Beveral varieties 



of over 30 per cent. By varying the environment under which s 1 was grown 



in 191G, yields ranging from 16,700 to 24,000 ll>s. per acre within the same 

 variety were secured in L917. Selecting culls from a crop grown from (-tins' 

 has not seriously reduced the yielding power of Bussel Burbank, Rural New 

 Yorker, or Early Bose Seed from thinned plats is said to have higher yield- 

 ing powers than thai from nnthinned plats. Very little difference was noted 

 whether Green Mountain potatoes were planted 12, L5, L8, or 24 in. apart in 

 the row. 



[Work with field crops on the Scottsbluff reclamation project experiment 

 farm in 1917], .7. A. BOLDER (I . 8. !>■ pt. AffT., Jinr. Plant h>>iiix.. Work SootU- 

 Muff Bxpt. Farm, 1917, pp. 18-14, i . - 1.— This reports the continuation 



of work along the same general lines as previously noted ( K. s. H., .">:>, p. 130). 



Alfalfa yields ranged from 3,44 tons per acre for native to 4.68 tons for Baltic 

 with an average of 4.i;» tons for the seven varieties te ted. Harrowing with a 

 spring-tooth harrow, disking, and manuring alfalfa resulted in yields of 4.33, 

 4.53, and 4.01 tons per acre, respectively, as compared with 4.43 tons from un- 

 treated checks. Alfalfa seeded alone in the spring after beets in the Irrigated 

 rotation experiments has produced a 1-year average yield of 1,55 tons per acre 

 the first season, as compared with 4.2] tons from alfalfa seeded in the fall in 

 oat stubble. 



Sugar beets thinned at the ordinary time and 10 and 20 days later resulted in 

 average yields amounting to 17. 10. 13.77, and 9.G1 tons per acre, respectively. 

 The decrease in the value of the crop due to late thinning Is estimated to hav* 

 been $18.G.~ per acre where thinning was delayed 10 days and $43.58 where it 

 was delayed 20 days. An average Increase in yield of sugar beets of 4.61 tons 

 per acre has been secured where the beets follow manure and ,VJ1 tons win re 

 they follow alfalfa the second and third season after it has been plowed up. 

 Alfalfa land, pastured by hogs receiving different quantities of grain during: I'.'l 1 

 and 1915, produced 316 bit. of potatoes in 1916 and 18.29 tons of beets in 1017. 

 as compared with 12ss;.,'{ hu. of potatoes and 16.72 tons of beets during the same 

 period from land producing alfalfa hay during 1914 and 1916, 





