32 



LAND DRAINAGE 



48. Effect of correct plowing on the later preparation of 

 the seed-bed. When the soil is plowed under proper 



FIG. 11. Same soil as is shown in Fig. 10. The excessive amount 

 of capillary water prevents its crumbling. Pressure fails to crumble 

 the soil. Instead it retains a waxy appearance and consistency. 



moisture conditions, the seed-bed can be perfected in the 

 shortest possible time, and with the least labor. There is 



an absence of lumps; the 

 soil feels soft and is crumby. 

 These crumbs are not soil 

 grains, as they are sometimes 

 supposed to be, but rather 

 masses of grains, or particles, 

 held together somewhat as is 

 the corn in a popcorn ball. 

 The chief difference is that in 

 the case of the soil crumbs, 

 the particles are held together 

 chiefly by a film of capillary 

 water. (See Fig. 12.) If 

 there had been too much water at plowing, the soil par- 

 ticles would have been rolled closer together by the action 

 of the plow. With the correct amount of capillary water, 



FIG. 12. Illustrating soil 

 crumbs. C, soil crumbs con- 

 sisting of soil particles held in 

 mass by capillary film. O, 

 openings between the crumbs. 



