THE IRRIGATION AGE. 



39 



PREPARING LAND FOR IRRIGATION AND METH- 

 ODS OF APPLYING WATER. 



From Bulletin 145, Courtesy U. S. Department of Agriculture. 



PREPARING LAND FOR IRRIGATION IN GALLATIN VALLEY, 

 MONTANA. 



In the Gallatin Valley, Montana, the greater part 

 of the plowing is done in the fall after the crop is har- 

 vested. Ordinary walking plows, sulkies, and disk 

 plows are used. Back furrows are avoided, if possible. 

 In the spring the plowed land is leveled, harrowed, and 

 seeded. 



LEVELING. 



A number of different devices are employed to re- 

 duce the surface to an even, uniform grade. Some of 

 these are homemade and cheap, while others are con- 

 trolled by patent rights and are more costly. Figure 



Sectiof> on AB 



G 



//wi fink, nfo/rt 8 (4 far each end) 

 Homemade land grader. 



3 represents one of the homemade land graders. Each 

 runner is made from two by six inch joist, sixteen feet 

 long, and is bolted to another joist of the same size, 

 but placed two inches higher, as shown in "Section on 

 AB" in the figure. The draft attachment, bracing, and 

 crossbars, shod with steel, are also fully shown in the 

 drawings. 



To finish off a field prior to seeding and give it a 

 smooth, uniform grade the leveler shown in Fig. 4 

 is preferred. The framework consists of five four by 

 four inch timbers, having their centers raised by wheels 

 thirteen inches above the ground. The machine is 

 twelve feet wide and seven feet long, and has an ad- 

 justable steel-shod share eleven feet two inches long and 

 nine inches deep. This implement, when operated by 



a competent man with three or four horses, will level 

 from ten to twenty acres in a day, providing the ground 

 is tolerably even. Details are shown by the drawings. 



When the surface is properly graded grain may be 

 sown with a three or four-horse seeder. In this work 

 care is taken to have the drills run in a direction to 

 facilitate the distribution of water between the field 

 ditches, since the water readily follows the drill marks. 



In the Gallatin Valley a cereal crop grows until 

 the plants are about six inches high before prepara- 

 tions are made to irrigate it. In average seasons the 

 seed is iisually in the ground by the tenth of May and 

 the rainfall during May and June in that locality is 

 seldom less than five inches and is often as high as seven 

 inches. This is sufficient to maintain the vigor of the 

 plant until it attains the height named. Cereals are 

 irrigated for the first time early in July. In dry sea- 

 sons the crops begin to suffer in June, when water must 

 be applied, although the plants may be only three inches 

 high. The better custom, however, and one which in- 

 sures larger yields, is to defer irrigation wherever pos- 

 sible until the plants cover the ground fairly well. 



ESTABLISHED GRADES FOR FIELD DITCHES. 



On the larger ranges of the State field ditches or 

 laterals are frequently laid out by means of the engi- 

 neer's level. When the slope of a forty-acre field does 

 not exceed eighty feet to the mile, the level is set up 

 in a position to command the upper half. The front 

 chainman carries a leveling rod and the rear chain- 

 , man a long-handled shovel. Sometimes the chain is 

 dispensed with and the distances are ascertained by 

 pacing. 



A beginning is made by holding the rod on the sur- 

 face of the ground at the highest corner of the field and 

 next to apply to the supply ditch. The target is then 

 read and raised, say three-tenths of a foot, and the front 

 chainman stretches the chain or tape to its full length 

 of 100 feet and endeavors to find a spot of the right 

 elevation to suit the rod reading. While the reading is 

 being taken and the target again shifted three-tenths 

 of a foot higher the rear chainman makes a mark in 

 the soil with his shovel. The driver of the ditch plow 

 follows the rear chainman, keeping at least 200 feet in 

 the rear of the latter, and, being seated on a sulky, he 

 can look ahead and improve on the grade location 

 marked out by curving the ditch in order to have fewer 

 sharp bends. 



A grade of twenty-five hundredths per 100 is ample 

 for fields that are carefully leveled, but if there are 

 surface irregularities it is well to increase the grade to 

 three-tenths, or even four-tenths, per 100. 



The homemade level shown in Fig. 5 is pretty gen- 

 erally used throughout the Gallatin Valley to locate 

 ditches and laterals. It is carried by one man, and an 

 assistant makes marks, as in the former case, with a 

 shovel, to guide the driver of the ditcher which follows 

 him. The usual grades allowed are from one-half to 

 three-fourths of an inch to the rod. 



In the majority of cases no instruments are used 

 to locate field ditches. The proprietor of an irrigated 

 farm becomes in time familiar with the slopes in dif- 

 ferent directions. He also learns from his experience 

 in irrigating the high and low portions. Possessing 

 such knowledge, he can usually locate the field ditches 

 hv eye and thus save considerable trouble and expense. 

 The inexperienced, however, should not attempt this 

 method. 



