EXERCISES 11 



Therefore, we have a continual flow of sap up from the root to leaves, 

 also a continual inflow of air, containing carbon gas, into the leaves, 

 where all is manufactured into plant foods and then returned in a 

 similar way to growing parts of the plant. 



EXERCISES 



Testing the Effect of Fertilizers. Materials: Nine 6-inch flower 

 pots; soil; sand; greenhouse or sunny window in warm room; 10 grams 

 sodium nitrate; 10 grams acid phosphate: 5 grams muriate of potash. 



1. Select soil that is of good texture but known not to be very 

 productive. Mix the soil with abo t one-half volume of sand. Fill the pots. 



2. Now add the fertilizing material to each pot. The fertilizer should 

 be ground up fine and thoroughly mixed into the soil. 



3. Fertilize as follows. (1) One gram sodium nitrate. (2) One 

 gram acid phosphate. (3) One half gram muriate -f potash. (4) One 

 gram sodium nitrate; one gram acid phosphate. (5) One gram sodium 

 nitrate; one-half gram muriate of potash. (6) One gram acid phosphate; 

 one-half gram muriate of potash. (7) One gram sodium nitrate; one 

 gram acid phosphate; one-half gram muriate of potash. (8<) No fertilizers. 

 (9) Ten grams fine barnyard manure. 



Planting Seeds. If you have a greenhouse or a good window in a warm 

 room, use a cereal, as oats or barley, planting 10 seeds to each pot. If 

 full light is not available use turnips, planting 10 seeds, but thinning to 5 

 plants. 



Observations. As long as the plants grow well, make notes twice a week 

 on following points: 



Size of plants. 



Color shade of green. 



Place together all the 4 pots having nitrogen as one element and com- 

 pare with rest for color and size. 



Rank the 4 containing nitrogen in order of growth and decide which is 

 best. 



Rank the 4 pots containing potash. 



Rank the 4 pots containing phosphate. 



Which element seems to increase growth most? How is color affected? 

 From your readings, which element is best for increasing forage production? 

 Grain production? 



COMPOSITION OP PLANTS 



Determination of Water. Take several samples of green or succulent 

 plants, as corn, grass, turnips, and potatoes. Weigh at once, then cut up 

 fine with a knife. Spread on paper and place in dry place for one week. 

 Determine loss of water. . , 



Then grind up finer and place weighed portion in oven at 110 C. (230 

 F.) and dry for two hours. Determine second loss of water. What per 

 cent of green material was dry weight? 



Take some air-dry hay and grain and grind very fine, then determine dry 

 weight. 



If possible, determine moisture in new corn and old, dry corn. 



Identifying Starch and Protein. It is sometimes difficult to get a 

 clear understanding of starch and protein. The following exercise will help 

 to an understanding: 



Starch is identified by the use of iodine, giving a decided blue color. 



