26 



FIELD CROPS 



The depth of covering and the fineness of the soil desirable 

 for best results depend largely on the size of the seed and the 

 consequent store of plant food it contains. Seed must be 

 planted deep enough so that it does not dry out after germi- 

 nation starts, yet not so deep that the plantlet will have 

 difficulty in reaching the surface. Such coarse seeds as corn 

 and peas should be 

 planted deeper than 

 clover and grass seed; 

 less care is also re- 

 quired in the prepara- 

 tion of the seed bed. 

 Very fine seeds, like 

 tobacco, may best be 

 sown by sprinkling 

 them on the surface of 

 a very fine seed bed 

 and pressing the seeds 

 into the earth with a 

 board. 



Too much water is 

 undesirable, for it ex- 

 cludes the air from the 

 soil. On the other 

 hand, a dry soil does 

 not contain moisture 

 enough so that the 



seed can take it up. The right kind of seed bed is a fine, 

 moist, mellow one; one which does not dry out readily and 

 yet allows plenty of air to reach the sprouting seeds. 

 WHAT THE LEAVES DO 



23. Assimilation. The leaves are the laboratory or the 

 work room of the plant. Three important processes are 



Fig. 0. A poorly drained field. Good 

 drainage, permitting the air to penetrate 

 the soil, is an essential condition for the 

 germination of seed and the growth of 

 plants. 



