Aug. i 4 , 1916 Agricultural Value of Impermeable Seeds 793 



I. RED CLOVER, ALSIKE CLOVER, WHITE CLOVER, AND WHITE SWEET CLOVER 



A. When seed is to be sowed in the late spring or summer. — Consider one-tenth of 

 the impermeable seed as good. Add one-tenth of the percentage of impermeable seed 

 to the percentage of germination. Calculate from this sum the quantity of seed of the 

 given lot necessary to give the desired quantity of good germinable seed. For exam- 

 ple: It is desired to sow per acre the equivalent of 15 pounds of viable seed none of 

 which is impermeable. Fifty per cent of the lot of seed to be used germinates and 

 40 per cent is impermeable. To 50 per cent add one-tenth of 40 per cent, or 4 per 

 cent. Consider 54 per cent as good. Then divide 15 by 0.54. The quotient, or 27.8, 

 is the number of pounds of seed to sow per acre. In the form of an equation we have 

 the following statement: 



I Number of 

 pounds 

 to sow 

 per acre, 



or ^ =27.8 



0.50-fcMo 



10 



The impermeable seeds remaining in the ground will constitute a reserve which, 

 under favorable conditions in a cold climate, will improve any thin areas in the stand 

 the following spring. This, however, should not be counted upon, as spots not occu- 

 pied by desirable plants before the second growing season will almost certainly be 

 appropriated by more rapidly growing weeds unless the field is unusually free from 

 weed seeds. 



B. When seeding in the late fall or winter or in the spring a month or so before the 

 end of freezing weather. — Consider all of the impermeable seeds as good. Add the 

 percentage of impermeable seeds to the percentage of germination. Calculate from 

 the sum the quantity of seed to be used, as under A. For instance, in the example 

 given under A add 40 per cent to 50 per cent, which gives a total of 90 per cent. Then 

 divide 15 by 0.9. The quotient, 16.7, is the number of pounds to sow per acre. Prob- 

 ably not all the impermeable seeds will soften and produce seedlings, but the seed- 

 lings produced by them will be less liable to injury than the seedlings produced by 

 permeable seeds which soften immediately, germinate on the first warm days, and may 

 be killed by subsequent freezing. 



C. When seeding in the spring after danger of severe frost but a month or more before 

 the end of cool weather. — Consider two-thirds of the impermeable seeds as good and 

 proceed as under A and B. 



2. ALFALFA AND CRIMSON CLOVER 



To the percentage of germination add two-thirds of the percentage of impermeable 

 seeds and calculate the quantity of seed to be used as given under red clover. More 

 than two- thirds of the impermeable seeds may germinate, but not soon enough to com- 

 pete with weeds. 



3. HAIRY VETCH 



To the percentage of germination add one-half of the percentage of impermeable 

 seeds as a basis for calculating the quantity of seed to be used. Proceed as under red 

 clover. 



4. OKRA 



To the percentage of germination add one-fourth of the percentage of impermeable 

 seeds as a basis for determining the quantity of seed to sow, and proceed as under red 

 clover. More than one-fourth of the impermeable seed will probably germinate, but 

 too late to contribute to a uniform stand. 

 52170°— 16 3 



