The Bulletin. • 85 



Some soils have larger capacity for holding water than otliers, as is shown 

 in tlie following table: 



100 ponnds sand will hold 25 pounds water. 



100 pounds sandy loam will hold 40 pounds water. 

 100 pounds clay loam will hold 00 pounds water. 

 100 pounds stiff clay will hold 61, pounds water. 

 100 pounds humus will hold 181 pounds water. 



By this table we see that humus will add greatly to the moisture-holding 

 capacity of the soil, as well as performing several other hnportant functions. 

 The hnnuis content of the soil can be kept up in many ways, as has been and 

 will yet be brought out in other papers upon the subject of soil improvement. 

 It is obtained through crop residues, by plowing under green crops, by grow- 

 ing catch crops when the land is not otherwise occupied, and by the applica- 

 tion of barn manures. 



For the encouragement of the sandy land farmer, it may be noted that 

 King has found that while sandy soils do not hold as much moisture as do the 

 clay soils, they yield a larger per cent of what is held to the crop, making the 

 amount of water available to the plants more nearly equal in the two soils. 



Underdrainage benefits the soil in many ways. As it relates to increased 

 moisture capacity it makes the soil more porous, permitting the water to sink 

 more readily into the soil. It permits the soil to be stirred earlier in the 

 spring, thus checking the evaporation of valuable moisture. It also increases 

 the capillary area of the soil by making it deeper and mellow, causing it to 

 pulverize easily, a very essential condition. A fine, mellow soil will hold 

 more moisture than will a hard, lumpy one. 



If we would grow large crops, which are a result of the best use of soil 

 moisture, there is no one thing more important for the farmer to strive for 

 than the earliest possible stirring of the soil in the spring, after the land has 

 sufficiently dried that injury will not be done. When the soil is close and 

 compact as left by the winter and early spring rains, and the spring winds 

 begin to blow, evaporation is rapid, and many tons of water are taken up 

 daily from the soil. 



In an experiment conducted for the purpose of measuring the influence of 

 early spring plowing on the loss of water from the soil, King finds as follows : 



On April 28th a piece of corn land was plowed; the next day samples of 

 this soil were taken in 1-foot sections to a depth of 4 feet, and the iiercentage 

 of moisture determined. Seven days later. May Gth, samples were again taken 

 as before and the percentage of moisture noted. There was no appreciable 

 change in the moisture content of the soil during the seven days. Adjoining 

 this piece of land and separated from it by strip of grass 10 feet wide, lay 

 another piece of land which was not plowed until May Gth, and on this date 

 before plowing samples of the soil were taken as before, and the percentage 

 of moisture ascertained as in the first instance. The experiment showed that 

 the unplowed laud had lost 9.13 pounds more water per square foot than had 

 the plowed ground, an amount equal to 1% inches of rain, and more than 198 

 tons of water per acre. Another serious result followed the delayed plowing. 

 The land broke up in large clods. So that instead of having the soil in excel- 

 lent tilth at one plowing and one harrowing, it was necessary to go over the 

 land twice with loaded harrow, twice with disc harrow, and twice with heavy 

 roller before it was brought into condition of tilth even approximating what 

 it might have had had it been plowed seven days earlier. 



It is encouraging to the farmer to know that in putting into practice 

 methods to check erosion, to deepen the soil, to improve the textural and 

 physical condition of his soil, to promote bacterial life, to increase soil fer- 

 tility, to liberate plant food, that he is also performing those operations that 

 tend to increased moisture capacity, and that oftentimes he is accomplishing 

 more than he knows. 



