PLANT FOOD IN THE SOIL 8 1 



fine leaf mold and mix thoroughly. Spread out each batch of soil 

 and add water carefully until the soil is moist enough to germinate 

 seeds, but not too wet. Replace the soil in the pots and settle by 

 jolting. Plant five kernels of corn in each pot, and weigh. Add enough 

 water every other day to replace that lost by evaporation, as shown 

 by repeated weighings. Keep in a warm, sunny window and for three 

 weeks continue to observe the growth of corn in each pot. Note and 

 explain results. 



2. Plant two sets of corn grains in pots of sand. Water one each 

 day with water which has been allowed to run slowly through some 

 decaying manure. Water the other pot with the same amount of pure 

 water. Note and explain results. 



3. Carefully dig up a sweet-clover, red-clover, or alfalfa plant and 

 locate on the roots the nodules in which the bacteria live. Compare 

 the nodules on the different kinds of legumes in your locality. 



REFERENCES 



BURKETT, C. W. Soils, chaps, vi-ix, xv, and xvi. Orange Judd Company. 

 HOPKINS, C. G. Soil Fertility and Permanent Agriculture, chaps, ii, iii, 



and-vii. Ginn and Company. 



KING, F. H. The Soil, pp. 71-153. The Macmillan Company. 

 LIPMAN, J. G. Bacteria in Relation to Country Life, chaps, xxi-xxiii. The 



Macmillan Company. 

 LYON, T. L., and FIPPIN, E. O. Soils, pp. 267-291. The Macmillan 



Company. 

 VIVIAN, A. First Principles of Soil Fertility, chaps, ii and iv. Orange 



Judd Company. 



