CH. XJ 



Effect on Soil Moisture 



181 



capacity. Fig. 35 gives curves showing the percentage 

 of water in the dunged plot and in the adjacent unma- 

 nured plot of the Broadbalk wheat field during 1913-14: 

 it will be seen that the former is invariably the moister 

 even in the very dry June. Indeed so great is the water- 

 holding capacity of the soil that the rain-water does not 

 distribute itself uniformly in the soil but remains in the 

 top few inches and rarely gets down to the drains in 



June. July. 

 1913 



Aug. Sep. Oct. Nov. Dec. 



Jan. 



Feb. Mar. Apr May. 



Fig. 35. Curves showing effect of farmyard manure on water 

 content of soils. (Broadbalk field, Rothamsted.) 



sufficient quantity to cause them to run. The unmanured 

 soil, on the other hand, is easily permeable to water, 

 becomes wet throughout its depth soon after rain has 

 fallen, and readily transmits water to the drains. The 

 numbers of days when the drains ran are as follows : 



