l6o8 AGRICULTURAL SEEDS 



iiupermeable. Considering one tenth of the latter, or 4 per eent, as good, then the amount 

 of seed required per acre would be 



15 



0.50 + 0.40 



27.8 lbs. 



The impermeable seeds remaining in the soil during the winter will help to improve any 

 thin areas in the stand the following spring, but this, however, should not be counted upon, 

 b) seeding in the late autumn or winter or in the spring a month or so before the end of freez- 

 ing weather : 



Consider all the impermeable seeds as good. Add the percentage of impermeable seeds 

 to the percentage of germination. Using the figures as in the preceding case (a) the quantity 

 of seed to use would be 



= 16.7 lbs. 



0.50 + 0.40 



c) When seeding in the spring after danger of severe frost is past, but a month or more before 

 the end of cool weather : 

 The general formula is 



Number of lbs. of good seed desired per acre 



Nimiber of lbs. to sow per acre ^ — 



Percentage of germination +73 of impermeable seeds. 



With the same figures as before the quantity of seed required would be 



15 15 



= := 19.7 lbs. 



0-50 + ^/s (0-40) 0.50 + 0.26 



2. Lucerne and crimson clover. 



The formula is again 



Number of lbs. of good seed desired ptr acre 

 Number of lbs. to sow per acre = 



Percentage of germination + ^/g percentage of imper- 

 meable seeds. 



More than two- thirds of the impermeable seeds may germinate, but the excess should not 

 be reckoned on. 



3. Hairy Vetch. 



Number of lbs. of good seed desired per acre 



Number of lbs. to sow per acre =^ —. 



Percentage of germination + /2 percentage of imper- 

 meable seed. 

 4. Okra. 



Number of lbs. of good seed desired per acre 



Number of lbs. to sow per acre = 



Percentage of germination -\- ^/^ percentage of imper- 

 meable seeds. 



More than one fourth of the impermeable seed will probably germinate but too late to 

 contribute to a uniform stand. 



I f 74 - The Seed of Commelina communis L. Characteristic of Seed Samples 

 derived from the Maritime Region of Eastern Siberia. — IIcAnenKo B. JI. 

 (IssATCHENKO B. ly.), SomirKii CtiiaHi{iii O.t }( KenhimaniH (ToMSiHo npu 

 Il.nnepamopcKOMo BomanuHf'CKO.uo C'adih Ilenipa BeAUKazo eh JJempozpadih 

 (Annals of the Seed Control Station at the Imperial Garden of Peter the Great at 

 Petrograd), Vol. Ill, Part 5, pp. 3-27. Petrograd, 191 6. 



As an auxiliary means of determining the place of origin of crop seeds 

 recourse may be had to the identification of the weed seeds which occur 

 mixed in the samples. This method demands numerous analyses of 



