36 VERMONT AGRICULTURAL REPORT. 



these meant greater plant food availability and increased croppage 

 have been appreciated for years. But that tillage, because of its 

 manysidedncss, is a more potent factor in crop growth than is 

 the fertilizer, is not as well appreciated by many farmers. Of its 

 many functions, however, all important, none worthy of disre- 

 gard, but one will be emphasized in this article, since space will 

 not admit of a thorough and all embracing discussion of the sub- 

 ject. Hence, without in the least minimizing the importance of 

 tillage as a carrier of available plant food to crop growth, as a 

 profound ameliorator of the soil, as a promoter of the growth of 

 desirable and a hindrance to the multiplication oi undesirable 

 forms of micro-organisms, as a means of aerating the soil or 

 as a means for the destruction of weeds, for the reason that they 

 are but briefly referred to, stress will be laid during the next few 

 pages upon the relationship of tillage to the conservation of soil 

 moisture, a function of the first rank. 



CONSERVATION OF SOIL MOISTURE. 



The productive capacities of a soil are measured not only by 

 its chemical composition and its physical characteristics, but also 

 by its moisture content. Its maintenance at as near an optimum 

 as may be should be the goal of the husbandman, for this, more, 

 perhaps, than any other one factor, is the measure of the crop's 

 success. Moreover, the available supply is more nearly within 

 his personal control than he is apt to think. So significant a mat- 

 ter, of such vital importance, warrants discussion in some detail. 



Water is the main life constituent — in point of amount. 

 From three-quarters to nine-tenths of plant, and from one-half to 

 four-fifths of animal structure is water. Each needs ample sup- 

 plies throughout life in order to attain to its full development. 

 Plant life in particular needs water in large quantity and in a 

 special form, while it cannot use it to advantage if in over- 

 abundant quantity or in the wrong form. 



Soil water exists in three different physical conditions or 

 "forms," all of them water, chemically alike, but physically un- 

 like and economically different. These are (i) hydrostatic or 

 standing water ; (2) hygroscopic or invisible water ; (3) capillary 

 or rising water : 



(i.) The standing water, the free running water of stream 

 and pond, the water of the wells, which permeates and fills the 

 soil at the lower levels and makes swamps and wet places, which 

 rises and falls with rains and drought, the water of the water 

 level or "water table" : 



(2.) The invisible water, enveloping the several soil parti- 

 cles, as it does almost everything on the earth, the pen with which 



