Oswald] 



SEED TESTING 



17 



Fig. n. Germinating Wheat at the End of Third Day. 



1. Percentage of pure seed. 



2. Percentage of dirt, chaflf. etc. 



3. Percentage of weed and other seeds. 



4. Kinds of weed seeds. 



In making a purity test care should be taken first of all to 

 get a good average sample of the seed which is to be tested. 

 The seed must first be thoroughly mixed; then a sample of 

 about a large handful should be taken for a test. This sample 

 may be called a trial sample. After the trial sample has been 

 obtained it should be placed on a flat surface, and then with a 

 strip of tin or thin board it should be cut into two equal parts. 

 If it is still too large it can again be divided, and so on until 

 a sample of the right size is obtained. This sample may be 

 called the test sample. The size of the test sample varies in 

 different seeds. For instance, a test sample of red clover should 

 weigh approximately ^osth of an ounce, while one of wheat 

 should weigh about one ounce. After the test sample is obtained 

 it should be divided into three piles : 1st. pure seed : 2nd. weed 

 and other seeds : 3rd. dirt, chaff, etc. These divisions can be made 

 with the aid of the forceps. In case no scales are available the 

 percentage of each pile can be estimated, but if such scales 

 can be obtained the percentage can be accuratelv worked out. 

 After this is done the weed seeds are compared with the seed 



