Water Used ~by Plants 



21 



*Table shoiving the amount of water evaporated from plant and soil in producing 

 a pound of dry matter in Wisconsin in 1891 



Dry matter Water per Ib. of Water as inches 

 Water used produced dry matter of rain 



LBS. LBS. LBS. INCHES 



13.19 



19.6 



26.39 



404.33 J 

 509.31 1 

 493. 63 J 

 295.95 1 

 307.03 J 



It will be seen from an inspection of the table that the sev- 

 eral experiments agree among themselves as closely as could be 

 expected, and that the barley used 13.19 inches of water in 

 coming to maturity, the oats 19.6 inches, and the corn 26.39 

 inches. 



During the same season an effort was made to measure the 

 water required for a crop of corn under perfectly normal field 

 conditions. To do this two plots of ground, each 48 feet long 

 and 42 feet wide, were planted to a local form of Pride of the 

 North dent corn, in rows 3.5 feet apart and in hills 16 inches 

 apart in the rows, the corn being thinned to two stalks in a hill 

 after it had come up and was well established. At the time of 

 planting, samples of soil were taken in 1-foot sections to a depth 

 of 4 feet from six different places on each plot, and the water 

 in the soil determined. This was also done when the corn was 

 cut, in order to get a measure of the change in the water con- 

 tent of the soil, which it was proposed to add to the measured 

 rainfall of the growing season, to give the amount of water 

 used. 



At the time of maturity, the whole of the corn of each plot 

 was cut and dried in a large dry-house, in order to get an exact 

 measure of the amount of dry matter produced. There is given 

 below the water content of the soil in the two plots at the time 

 of planting and at the time of harvest : 



*Eighth Annual Report Wisconsin Experiment Station, p. 126. 



