22 BULLETIN 995, U. S. DEPARTMENT OF AGRICULTURE. 



beets, and should be allowed to flow until the soil is thoroughly wet. 

 The head of water which is used in furrow irrigation must not be too 

 large, as shown in Plate III, figure 2. The size of the head must be 

 governed bj the slope of the land, by the nature of the soil, and by 

 the number of furrows that can be irrigated at one time. 



Leveling. —In order that irrigation may be properly done the field 

 must be carefully leveled, as shown in Plate V, figure 2. This is 

 frequently a limiting factor on many fields and occasionally in an 

 entire community. The lack of success in at least one sugar-beet 

 area is due primarily to the failure of the growers to level the ground 

 properly. It usualty requires several years to level a field properly 

 for furrow irrigation, for the reason that the depressions that are 

 filled during the first effort to level the field will usually settle and 

 still leave slight depressions, while the higher points from which 

 the soil was removed to make the fills do not settle, and an uneven- 

 ly ess results. If the leveling process is repeated for two or three years 

 the ground generally becomes sufficiently level to admit of furrow 

 irrigation. If the ground is very uneven the Fresno scraper may 

 often be used to good advantage. In some localities the surface of 

 the soil is by nature sufficiently level to admit of proper irrigation. 

 In other sections the slopes are sufficiently long and the source of 

 the water supply so high that it can be carried to the highest point 

 and distributed over large areas without the expense of leveling the 

 ground. In the process of leveling, the better surface soil is removed 

 from the high point and carried to the depression. It is then neces- 

 sary to improve the areas from which the better soil has been re- 

 moved, either by the use of stable manure or a leguminous crop. 

 Sometimes several years are required to make a leveled field uniform 

 in fertility as well as in firmness of surface. 



A very coarse soil, especially if it has a porous subsoil, is irri- 

 gated with great difficulty, and frequently much time and money 

 are wasted in leveling such lands, as they are not adapted to the 

 growing of sugar beets or other intensively cultivated crops. 



DRAINAGE. 



Drainage has an important bearing upon sugar-beet growing in 

 general, as well as upon the production of other farm crops. Large 

 areas of land that are now too wet to be cultivated could be put under 

 tillage and would produce good crops if properly drained. Other 

 large areas now under cultivation are in manj^ instances becoming 

 water-logged, especially in the irrigated sections, and will soon be 

 unfit for crop production unless they are drained. In some instances 

 the further expansion of the sugar-beet acreage is limited to the 

 bringing in of areas through drainage. 



