FIELD CROPS. 225 



FIELD CROPS. 



Dry-farming' investigations in western North Dakota, J. C. Thysell, H. C. 

 McKiNSTRY, li. S. TowLK, and A. J. Ogaabd (Norih Dakota Sta. Bui. 110 (1915), 

 pp. 155-201, figs. 11). — This bulletin presents a study of the annual and seasonal 

 precipitation; evaporation; length of frost-free period; the soil moisture storage 

 and reduction as affected by various crops ; and rates of seeding and methods 

 of tillage derived from data obtained at the stations at Dickinson, Hettinger, 

 Edgeley, and Williston, N. Dak., in cooperation with the U. S. Department of 

 Agriculture in determining the best methods of soil cultivation and crop rota- 

 tion for the conservation of moisture and maintenance of humus. 



It is noted that on account of the lack of an underground water table ordi- 

 nary methods of cultivation which would develop a mulch are of no avail as 

 a means of storage of soil moisture. Cultivation to prevent the growth of 

 weeds proved more effective. In studying the reduction of soil moisture by 

 plant growth it is shown that wheat roots penetrated to the sixth foot and 

 corn roots to the fifth, as evidenced by the reduction of the moisture supply. 



The following conclusions have been reached : " Climatic conditions are the 

 chief determining factors in crop production in western North Dakota. The 

 amount of rainfall during the growing season is a better criterion of crop 

 production than is the annual rainfall. Available records show the average 

 frost-free period to be 129 days at Edgeley, 119 days at Williston, and 110 

 days at Dickinson. Even with alternate cropping, water is seldom stored to a 

 greater depth than that from which annual crops can recover it. 



" While stored water may be of value in supplementing rainfall, it is unable 

 in itself to mature a crop in western North Dakota. Shallow soils are not as 

 responsive to tillage as are deeper soils. Prevention of the growth of weeds 

 is a much more important function of cultivation than is the maintenance 

 of a mulch. Summer tillage has a certain value as insurance against crop 

 failure. It has not, however, increased average yields over those obtained by 

 other methods enough to warrant giving it more than a secondary and tem- 

 porary place in the agriculture of this section. 



" The application of barnyard manure has shown marked value. Sod crops 

 should not enter into short rotations. Neither fall nor spring plowing has a 

 marked advantage of one over the other in the average of a series of years. 

 Disking land upon which a crop of corn has been raised, and kept free from 

 weeds, is as good a preparation for the succeeding grain crop as plowing." 



Dry farming in Egypt, Alchevski {Bui. Dir. G6n. Agr. Com. et Colon. 

 Tunis, 18 (lOlJf), No. 80, pp. 583-^87). — This article describes irrigation experi- 

 ments conducted with wheat and barley in wooden tanks of 1 square meter 

 surface and 1 cubic meter capacity. The amounts of water used ranged from 

 100 to 700 liters per tank. 



In the case of the barley a constant yield was not reached. The yields of 

 grain increased regularly with the increase in irrigation water and ranged 

 from 23 to 247 gm. per tank. In the case of the wheat the constant weight was 

 reached with the application of GOO liters of water per tank. The wheat yields 

 ranged from 92 to 304 gm. of grain per tank. The maximum amount of water 

 used reached 1 cubic meter per square meter of soil surface. 



[Report on the progress of farm crops investigations] (Missouri Sta. Bui. 

 131 (1915), pp. 475-477, 484-486, fig. l).—ln experiments with cowpeas and soy 

 beans by J. C. Hackleman it is noted that rows spaced from 30 to 36 in. apart 

 gave the best seed production and that 60 lbs. of seed per acre gave the largest 

 hay yield. Canada peas and oats gave the best mixture for spring forage 



