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240 AGRICULTURAL CHEMISTRY 



Malted or germinated seeds weigh less than the original 

 seeds. 



338- Heavy- and Light- Weight Seeds. While seeds 

 are quite constant in chemical composition, there is, 

 however, a slightly greater amount of total plant food in 

 heavy- than in light-weight seeds. In the case of wheat, 

 experiments have shown that the additonal reserve food 

 in heavy-weight seeds favorably influences the growth of 

 the crop, particularly when the soil is slightly deficient 

 in available plant food. The additional reserve food in 

 heavy-weight seeds enables the young plant to reach a 

 higher stage of growth before being compelled to collect 

 and assimilate food from the soil. When the soil is in a 

 high state of fertility the difference in results between 

 light- and heavy-weight seeds is less noticeable. 



Experiment 67. Calculation of plant food in seeds. Weigh 

 100 plump, well-formed wheat kernels. Then from this weight 

 and the following data compute the grams of nitrogen, phosphoric 

 acid and potash per 1,000 wheat kernels. Wheat contains about 

 2 per cent, nitrogen, and 90 per cent, dry matter. The dry matter 

 contains about 2 per cent, ash, approximately 50 per cent, of the 

 ash being P 2 O 5 , and 33 per cent. K 2 O. Repeat the experiment, 

 using 100 shrunken wheat kernels. Tabulate and compare the 

 results. 



Questions. (i) How much more reserve plant food is there as 

 N, P 2 O 5 and K 2 O in heavy-"than in light-weight seeds ? 



Movement of Plant Juices 

 339. Joint Action of Chemical and Physical Agents. 



The compounds produced in the leaves of plants are 

 transported and stored in other parts, as the seeds or 

 roots ; this is brought about by the joint action of 



