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IRRIGATION IN CONNECTICUT. 219 
It has been estimated that a crop of hay at two tons per acre, 
or about six and one-half tons of fresh grass, will evaporate 
during its season of growth about 525 tons of water; that an 
average crop of wheat, of 720 pounds of grain and 1500 pounds 
of straw to the acre, will evaporate about 260 tons of water, or, 
in other words, according to these estimates, every ton of 
green grass evaporates through its foliage during the period of 
growth about eighty-one tons of water, and in drying, this ton 
of grass loses about two-thirds of its weight, so that one-third 
of a ton of hay (667 pounds), utilizes in its growth about eighty- 
one tons of water. An inch of rainfall is equal to 113 tons of 
water per acre. The above figures indicate that the water 
evaporated by the hay crop would equal about four and six- 
tenths inches of water and the wheat crop two and three-tenths 
inches. ‘These figures, of course, only represent averages. In 
very moist times evaporation would be checked and in dry 
times it would be increased. In other words, at the times 
when the plant uses water most rapidly there is the least avail- 
able amount from the rainfall. 
The importance of water in the growth of crops may again 
be illustrated in a remarkable way by the experiments in water 
culture which have been carried on for many years, especially 
in the German Experiment Stations. In these experiments 
plants are grown, not in soil at all, but with their roots 
immersed in water. ‘The seeds are allowed to sprout in some 
convenient medium, as sand or moist cotton, or in an apparatus 
devised for the purpose. When the roots are started the 
plantlets are suspended at the tops of jars so that the roots dip 
into water with which the jars are nearly filled. The water in 
the jars holds in solution the materials which the plantlets 
ordinarily obtain from the soil. The roots find this material in 
the water, use it, and the plants grow. Solutions containing 
all the essential soil ingredients of plant food are called normal 
solutions. In these plants are raised as large and healthy and 
in every way as perfect as those grown in even the richest 
soil. 
The same principle as that illustrated in water culture is 
involved in all growth of plants by irrigation. In the irrigated 
regions of Lombardy, in Italy, eight or nine or more crops of 
grass are frequently cut in a single season. On the same land | 
