WATiai SUPPLY FOR CROPS. 19 



are also serious objections to the artificial application of 

 water to the surface in dry weather. Such applications of 

 water tend to increase the evaporation from the soil, which 

 at such times is naturally excessive, owing to the diy state 

 of the atmosphere ; it also has the effect of compacting the 

 soil, which tends largely to increase that evaporation. It 

 also has the effect of l)ringing the roots nearer the surface, 

 where they are more liable to feel the hot sun, and to suffer 

 from any failure of a constant supply of water. The artifi- 

 cial application of water increases the demand for its use, 

 and when once commenced renders a constant application of 

 it necessary. But there are other means for protection 

 against drought. 



Dr. E. L. Sturtevant, in three years' observations on the 

 percolation of water through the soil of his Lj'simeter at 

 South Framingham, found that of the annual rainfall of 

 47.15 inches only 8. 7 inches or 17.9 per cent, percolated 

 through the 25 inches of grass-covered sandy soil of his 

 Lysimcter. 



Prof. Stockbridge, in observations covering the seven grow- 

 ing months of the season, found, out of a rainfall of 25.7 

 inches during the time observed, a percolation of only 5.14 

 inches, or 20 per cent, of the amount of rainfall, passed 

 through the 36 inches of soil in his Lysimeter at Amherst. 



Bv these observations, conducted in our own State, in 

 both cases on leachy soils of only 25 and 36 inches depth 

 respectively, we are shown the great absorptive power of 

 our poorest soils. In both cases all the Avater Avhich fell on 

 the surfiice was forced into the ground, and none of it al- 

 lowed to flow off, as it often does when unobstructed. 



If such shallow depths of porous soil can absorb and hold 

 until given off by evaporation, so large a per cent, of the 

 rainfall, it would be interesting to know how much of it a 

 retentive loam of a much greater depth could hold. I think 

 that these observations indicate to us the practical way to 

 secure the water supply for our crops. And that is : 1st, 

 to increase, where it seems to need it, the absorptive power 

 of the soil, and 2d, to check evaporation in dry weather, 

 so far as we can, in order to retain the water which the soil 

 has absorbed for the use of our crops. 



