Mulches to Conserve Moisture 143 



inches with a Tower cultivator, and adjacent rows were culti- 

 vated to a depth of 3 inches with narrow shovels, it was found at 

 the end of the season that the ground cultivated 3 inches deep 

 contained 1.478 inches more water than the 1-inch cultivation 

 did in the upper 4 feet, the conditions of the soil being as repre- 

 sented below : 



1st foot 2nd foot 3rd foot 4th foot 



PER CENT PER CENT PER CENT PER CENT 



Cultivated 3 inches deep 23.14 23.3 21.94 22.46 



Cultivated 1 inch deep 22.7 21.08 19.65 19.58 



Difference .44 2.22 2.29 2.88 



These differences do not show the amount of water which the 

 deeper mulch saved, because at several times during the season 

 the rains may have brought the soil of the two kinds of treat- 

 ment very close together in their water content, the results above 

 being simply the final difference. They do show, however, how 

 much more moist one soil was kept than the other, and, hence, 

 how much better were the conditions in one case than in the 

 other for plant growth. 



That the full significance of such differences in soil moisture 

 in crop production may be better appreciated, Fig. 25 shows the 

 growth of corn under every way similar conditions, except that 

 the amounts of water in the soil in which the corn was large 

 and in which it was small were as stated in the table which 

 follows : 



Moisture in soil Moisture in soil 



of largest corn of smallest corn 



PER CENT PER CENT Difference 



Firstfoot 13.29 10.18 3.11 



Second foot 17.23 16.33 .9 



Third foot 19.17 18.63 1.08 



Fourth foot 16.21 15.48 .73 



These differences, it will be noted, are much smaller than in 

 the case cited above. But let it be observed that the difference in 

 the surface foot here is very much larger than there, and it is the 

 shortage of water in this layer which is chiefly responsible for the 

 difference in growth shown in the figure, 



