8 4 



FARM DEVELOPMENT 



Figure 33. Soil satu- 



apart, and the interstices among the threads between 

 the two wicks being too large to form capillary spaces, 

 little or no oil rises to the flame. In Figure 33, at a 

 depth of several feet, A, there is ground water ; at B, the 

 soil is well supplied with capillary water; at C, as is 

 often the case in very dry sections of 

 the country, a layer of coarse straw, ly- 

 ing up dry and loose, is plowed under. 

 The moisture cannot pass by capillary 

 movement upward through the layer 

 C, to moisten the furrow-slice, D, and 

 the " moisture line," or the zone of 

 capillary moisture, rises only to C; 

 thus shutting off the seeds from ob- fhe th tup P iy 



... f T\ ,1 M water. At C, a layer of 



taming Water from D, jUSt aS the Oil coarse straw is repre- 



_ ' J sented as having been 



fails to rise to the flame in the lamp plowed under the fur- 



r row-slice, D. 



in Figure 32. The layer of coarse straw 

 makes a mulch of the entire furrow-slice, protecting the 

 moisture below from rising and wasting by evapora- 

 tion, which causes 

 injury by forcing the 

 roots of the plants to 

 feed only in the sub- 

 soil. In most coun- 

 tries there is sufficient 

 moisture so that a 

 layer of dry straw soon 

 decays and no longer 

 acts as a barrier be- 

 tween the subsoil and 



Figure 34. E, subsoil. D, furrow-slice with , . . r _ 1 



dust blanket at surface shown darker. Upper the furrOW-SllCC. The 

 surface of capillary water here rises through the 



lower half or two-thirds of the furrow-slice, F, Stronger CaOlllarV 

 to the bottom of the dust blanket, C. J 



power of the decaying 



plant substance, on the other hand, secures and holds 

 within itself larger amounts of water, and thus both 

 water and plant food are most liberally supplied to the 



