HOW MOISTURE IS TAKEN UP BY PLANTS 89 



EXERCISE 85 

 CONTENTS OF A FERTILE SOIL 



Apparatus and Materials. Three one-quart flower pots, clay, sand, 

 garden soil (loam), ammonium nitrate, potassium chloride, powdered 

 rock phosphate or bone meal, 3 glass covers, oats. 



a. Into each of 3 one-quart flower pots put a layer of clay 

 2.5 cm. (1 in.) deep. Fill the first pot with good garden soil, 

 the second with clean sand; for the third make the following 

 mixture: a scant pot full of clean sand, half a teaspoonful of 

 ammonium nitrate, 24 of a teaspoonful of potassium chloride, 

 a tablespoonful of powdered rock phosphate or bone meal. 

 Mix these materials thoroughly, and fill the third pot with the 

 mixture. Label the third pot. 



b. Provide each flower pot with a glass cover. Soak some 

 oats over night (not longer) in water; then plant 16 of the 

 soaked seeds in each pot, about M of an inch below the surface. 

 Put down the date of planting. 



Cover the pots with the glass covers, and set them in diffused 

 light (not direct sunlight) in a warm room. Keep the soil moist 

 but not soggy. Note how long it takes for the seeds to sprout 

 (record the date) ; then remove the covers, set the young 

 plants in the sunlight, and watch their growth from day to 

 day for several weeks. 



c. Do all the seeds sprout? In which pot do the seedlings grow 

 most rapidly? What necessary plant food is supplied by each of 

 the 3 materials mixed with the sand of the third pot? Does 

 garden soil contain these plant foods? 



EXERCISE 86 

 HOW MOISTURE IS TAKEN UP BY PLANTS 



Apparatus and Materials. Egg, napkin ring or wide-mouth bottle, 

 glass tubing 7 cm. long, candle, iron wire (thick hair pin), hat pin, egg 



