EXPERIMENT STATION BULLETINS. 



155 



IC3 S^.Cyrt 



Ty^c of Soil %uc k Totaro . 



JIfQ. m . oj'frain ■ fijssf }rt. m. .02/ f 7 /n. m. 



2C>.d3 S^.Cmi. 



o 



^5-7 ^/.^//z- 



o 



lifhtqt. 



.Qoji, m 111. 



Grrass- 



.OOt^fSTG 771. 111. 



Cut II. 



2. What appear to be grains of soil in mellow loams and clays are usually 

 not grains, but crumbs — composites consisting of tens, hundreds, and even thou- 

 sands of individual or simple grains, held together partly by cementing materials 

 in the soils and partly by water contained in the composites. Not only does the 

 water help in developing this crumb-like condition, but a soil in this condition 

 will hold naturally the largest possible amount of water for the use of crops, 

 and at the same time will retain larger amounts from loss by percolation and 

 evaporation. 



3. The organic matter in a soil and especially the humus acts as a sponge 

 would act. Its relative capacity for holding water is considerably greater than 

 that of the mineral matter as you may have observed. Hence the importance 

 of returning to our soils, especially to our loams, clays, and sandy soils, as much 

 of the roughage of the farm as pflssible, and hence, also, the importance of follow- 

 ing a careful rotation which shall result in part in an abundance of root material 

 in the sub-soil. 



Good applications of barnyard manure increase the water-holding power of soils. 



