38 VERMONT AGRICULTURAL REPORT. 



the great California valleys where wet and dry seasons alternate, 

 and where marvellously deep retentive soils are stocked with 

 moisture against the needs of the dry growing season, would 

 not obtain in the East and vice versa. 



The nature of the soil on which the rain falls is well under- 

 stood to be a determining factor. A soil of compact texture, the 

 particles of which are finely subdivided, holds water tenaciously, 

 while one of open texture, with relatively coarse particles, leaches 

 readily. The one may be so impervious that water runs ofif of 

 rather than into it, the other so porous that the drainage is almost 

 complete. Many gradations between these extremes exist. While 

 the dense clays and drifting sands and soils closely allied there- 

 unto do not lend themselves readily to treatment, the more inter- 

 mediate soils may be bettered as to their moisture relations. 

 Soils of a clay type may be so handled as to render them more open 

 and porous, to separate the too closely agglutinated soil parti- 

 cles, to gather considerable numbers of them into crumbs or 

 granules. Liming does this, improving texture, cementing soil 

 particles into masses, opening up and aerating the soil.^ The 

 use of barnyard manure, the plowing under of green manures 

 are also advisable, though less effective.^ 



Oddly enough a similar treatment of sandy soil works advan- 

 tageously, since liming tends to lessen the rapidity of percola- 

 tion of water to lower levels, while the liberal use of manure 

 introduces material of a highly absorptive and retentive character. 

 In each case the ultimate result is the enhancement of the power 

 of the soil to conserve soil moisture for plant uses. 



The usage of zvater by plant growth is tremendous. The 

 amount seems incredible to those not well informed. From 200 

 to 600 times the weight of the dry matter of the crop is pumped 

 up by the roots into the circulation of the plant and passes off 

 into the air from the leaves, the amounts varying with the nature 

 of the crop and averaging not far from 300 times the dry weight. 

 This means that a ton of hay, for instance, has used during 

 growth somewhere in the vicinity of 300 tons of soil moisture, 

 that a dry corn stalk weighing a pound has during its four months 

 of growth pumped out of an apparently dry soil and vaporized 

 from the surface of its leaves approximately 300 pounds of water. 

 Large crops of hay, of corn or of potatoes draw several millions 

 of pounds of water from an acre. The variation in the visage of 

 water by the sundry crops is due largely to differences in the 

 character and extent of their root and leaf areas, the inlet and 

 outlet respectively of the moisture. Broad leaved plants naturally 



'See Vt. Sta. Bui. 99, pp. 102-103 (1903) on practice of liming. 

 -In this connection see statement under Drainage on pages 170-171. 



