656 EXPERIMENT STATION RECORD, 



"At the tiiiii' of the lirst irrifiatioii wheat an<l <iats had (h-aincfl tlic noil more eom- 

 jiletely of its moisture than liad ooni, ))otatoes, or su^jar beets. I'eremiials use less 

 water in early spring than <lo anmials. 



"The amount of water lield by the soil decreases with the depth. 



"Only about 00 })er cent to 75 per cent of the maximum water capacity of the soil 

 is utilized one day after irrigation. 



"The lateral movement of water in the soil of the college farm is about 4.1 ft. for 

 the first foot; 6 ft. for the second foot. On soils like those of the college farm the 

 lateral movement of the soil water is of little consequence to the farmer. 



"The loss of the soil moisture is greatest from soil which has received most water, 

 and is in direct i)roportion to the percentage of moisture in the soil immediately after 

 irrigation. Of 2 soils having the same percentage of moisture, the deeper soil loses 

 most moisture. The longer the time that elapses after an irrigation the more water 

 is lost. About one-half of the water added in an irrigation is evaporated during the 

 first week. All tillage, having in view the conservation of soil moisture, should 

 [therefore] be put into operation as soon as i)0ssible after irrigation. 



"The effect on the soil moisture in changing the relative humidity a few degrees 

 is very slight. Sunshine is a strong factor in causing a loss of soil moisture. Of the 

 3 factors, relative humidity, sunshine, and temperature, the last is most potent in 

 causing a loss of soil moisture. Winds cause a large loss of soil moisture. 



"The rate of loss of soil moisture depends upon the kind of crop. The order, 

 beginning with the most wasteful, is the following: Potatoes, oats, wheat, corn, sugar 

 beets, old lucern, red clover, timothy, and English rye grass. 



"The soil moisture is taken nearly at the same rate from the different depths, 

 though the upper soil layer dries out first. The extent to which soils can dry out 

 was 2.13 per cent for the first 3 in., 3.72 per cent for the first foot, and 4.63 per cent 

 for the second. More water is lost from the furrow than from the row, though the 

 soil under the row is quite moist. 



"The percentage of water in j^lants and in the ripe seeds increases slightly with 

 increase in irrigation. Heavy irrigations increase the percentage weight of the heads 

 of plants; light irrigations increase the relative weight of leaves. Irrigation modifles 

 definitely the composition of plants and plant parts; the seeds are affected more 

 than any other plant part. The percentage of protein in corn kernels was increased 

 from 12.05 to 15.08 as the amount of irrigation decreased, in oat kernels from 14.07 

 to 20.79, in wheat kernels from 15.26 to 26.72. In all these seeds the fat and nitro- 

 gen-free extracts were increased by liberal waterings. Increased irrigation increased 

 the starch content and decreased the protein content of potatoes. The composition 

 of sugar beets seemed to be less strongly affected by irrigation than were other 

 crops. Between 20 and 25 in. of water yielded beets with the highest sugar content. 

 The water in plants is somewhat dependent on the water in the soil. 



"With a given amount of water, better yields of corn were obtained by flooding 

 than by furrowing. Late irrigation did not affect unfavorably the growth and yield 

 of corn. The proportion of ear corn to stover increased regularly with the increased 

 application of water. The best amount of water for corn lies between 20 and 25 in. 



"Late irrigations were found very beneficial in transferring nutritive materials 

 from oat stalks to the heads. Not less than 15 in. of water should be used for oats, 

 and not more than 30. 



"Late irrigation was beneficial for the wheat crop. The percentage of grain in 

 the wheat cro^) increased with increased irrigations. The yield of wheat increased 

 up to 30 in. of water. 



"Frequent small irrigations of potatoes produced the best yields. The percentage 

 of marketa])le potatoes increased with irrigation. 



"The best amount of water for sugar beets is about 2(; in. 



